Popliteal artery Chapter 22 / Soleus and Plantaris Muscles 433 Gastrocnemius, Tibial nerve medial head Popliteal vein (cut and reflected) Gastrocnemius, lateral Soleus head (cut and reflected) (cut and reflected upward) Femur Tibia Posterior tibial veins Fibula Posterior tibial artery Soleus canal Tibial nerve Peroneal artery and vein Flexor digitorum longus Tibialis posterior Flexor hallucis longus Tibia Tibial nerve Flexor digitorum Fibula Talus longus tendon Flexor hallucis Tibialis posterior tendon longus tendon Flexor retinaculum Achilles tendon, cut Plantaris tendon (cut) (attachment of soleus and gastrocnemius tendons) Calcaneus Figure 22.6 The soleus muscle (dark red) has been the adjacent musculature (light red). This is an artist's reflected upward showing the distal opening of the reconstruction of what the canal would look like if it soleus canal and its relation to the tibial nerve (white), were possible to reflect the muscle without cutting its to the posterior tibial artery (bright red), to the poste- proximal attachments to the tibia and fibula. The gas- rior tibial veins, (black cross hatching), and to trocnemius muscle is cut and reflected. of the accessory muscle is found in Karger's The accessory soleus is of special clinical im- triangle and replaces the fibrofatty tissue that portance because it may be mistaken for a tumor, usually occupies this space above the ankle as discussed in Section 6 of this chapter. joint between the Achilles tendon and the tibia. The accessory soleus muscle has been Fiber Types and Size described as covered with fascia that is sepa- rate from the soleus muscle.110 The proportion of slow-twitch, type 1 muscle fi- bers that depend on oxidative metabolism is Proximally, the accessory muscle fibers merge higher in the soleus (70-75%) than in other mus- with the soleus muscle at about midleg. Distally, cles of the lower limb.36 Two other studies ob- it sometimes attaches to the anterior (deep) sur- served a similar relationship between the soleus face of the Achilles tendon and sometimes di- muscle and the vastus lateralis.37, 140 The soleus rectly to the calcaneus.42,80,81,113,130,153 comprised about 75% type 1 (slow-twitch) fibers
434 Part 3 / Leg, Ankle, and Foot Pain Soleus Figure 22.7. Attachment of the soleus Tibialis posterior portion of the right Achilles tendon to the os calcis, posterior view. Note the ten- Flexor don's rotation of 90° and attachment to hallucis the medial one-third of the calcaneus. longus The gastrocnemius portion of the tendon (not shown) attaches to the lateral two- thirds of the os calcis. [Reproduced with permission.96] Flexor digitorum longus Soleus and the vastus lateralis about 50%. The percent- nearly the same weight as the gastrocnemius mus- age of type 1 fibers in the soleus muscle was cle. The average fiber length of both the soleus higher in six athletic young adult men (79%) than and gastrocnemius muscles was quite short, 3.7 in six comparable women (67%).140 and 3.5 cm (1.5 in). Elder and associates37 found that the variability Plantaris in the distribution of fiber types was so large that (Fig. 22.4) five sites must be sampled from the same muscle to keep the standard deviation below 5%. Because it attaches proximally beside the lateral head of the gastrocnemius muscle, Weber157 reported that the muscle fibers of the the plantaris can be thought of as an ac- soleus muscle weighed 335 g, about one-fourth cessory lateral head of that muscle. The the weight of the gluteus maximus muscle and _
Chapter 22 / Soleus and Plantaris Muscles 435 plantaris is a small, frail muscle, the fi- subtendinous calcaneal bursa reduces friction be- bers of which angle across the capsule of tween the Achilles tendon and the calcaneus near the knee joint in the popliteal space (Fig. the tendon's attachment.46,47,106 22.4). Its proximal attachment is on the femur along the lateral prolongation of A complete series of cross sections is available the linea aspera proximal to the attach- for the soleus muscle and Achilles tendon24 and ment of the lateral head of the gastrocne- for the plantaris muscle and its tendon.23 Selected mius muscle.86 The muscle then crosses cross sections can be seen of the soleus and plan- to the medial aspect of the popliteal space taris muscles at the upper third of the leg,26,49, 115 at where it becomes a thin tendon that lies the middle third of the leg,1,116 and at the lower between the gastrocnemius and soleus third of the leg.27,117 The distal sections show the muscles. Distally, the plantaris tendon relations of the plantaris and Achilles tendons to runs along the medial border of the tendo the space in Karger's triangle that lies between the calcaneus29 (Fig. 22.4) and attaches with tendons and the posterior surface of the tibia. This it to the calcaneus. Most of the muscle space is occupied by the accessory soleus muscle, belly is covered by the lateral head of the when present. gastrocnemius. A sagittal section through the knee joint shows The plantaris is a rudimentary muscle that is the soleus muscle.125 The proximal bony attach- analogous to the palmaris longus of the upper ex- ments are marked for the plantaris muscle2,44,86 tremity.64 Like the palmaris longus, it is exceed- and for the soleus muscle.2,44,87 The attachments of ingly variable in origin, structure, and insertion,10 the Achilles tendon88, 127 and of the plantaris ten- and has been reported as absent in 6.2-7.5% of don88 are marked on the calcaneus. lower extremities.64 3. INNERVATION Supplemental References The soleus muscle is supplied by a The surface contour of the soleus muscle is shown branch of the tibial nerve that contains fi- bers from the first and second sacral spi- from in front43 and from the lateral side.26,78 The nal nerves. The branch of the tibial nerve that supplies the plantaris muscle con- edges of the muscle can be seen from in front in a tains fibers from the fourth and fifth lum- bar and first sacral spinal nerves.29 dissection.128,142 4. FUNCTION The superficial upper half of the soleus is pre- During normal walking, electrical activity sented from behind without vessels or nerve, of the soleus begins with toe-off of the op- posite foot and ends as the opposite heel alone,3 and with the plantaris muscle.48, 147 Rear strikes the ground. The function of the muscle appears to be that of resisting the views of the plantaris and upper portion of the su- kinetic force of forward movement.144 The plantar flexors (including the soleus) first perficial soleus muscle include the posterior tibial produce a lengthening contraction and, later, a shortening contraction during vessels and tibial nerve entering the soleus ca- stance. This muscle activity contributes to knee stability, provides ankle stability, n a l . 6 4 , 1 0 4 , 1 1 4 , 1 2 6 The plantaris muscle belly is shown restrains the forward rotation of the tibia on the talus, and conserves energy by in detail.92 The entire plantaris muscle and the su- minimizing vertical oscillation of the body's center of mass; this activity does perficial surface of the soleus muscle, including not ordinarily propel the body forward.145 According to Perry,118 the soleus helps re- the Achilles tendon, are seen from behind.143 Par- strain the valgus thrust on the ankle that occurs during single-limb balance. tial removal of the soleus reveals the posterior tib- Together, the soleus and gastrocnemius ial vessels and tibial nerve penetrating the soleus muscles compose the triceps surae, the primary plantar flexor of the foot. Of canal.4,45,65,91,105 An illustration with the edges of these two muscles, only for the soleus the soleus arch cut portrays clearly the short ex- tent of the soleus canal, approximately 2.5 cm (1 in).90 The Achilles tendon is viewed from the medial s i d e , and5 , 4 6 , 1 0 6 , 1 2 7 from the medial side and be- low.93 The soleus muscle is viewed from the me- dial side.46, 127 As seen from the lateral side, the muscle is illustrated alone47,8,9 103, 141 and with the Achilles tendon.30 The lateral view of the tendon appears in detail.94,108 The subcutaneous calcaneal bursa provides a cushion between the attachment of the Achilles tendon at the heel and the overlying skin.106 The
436 Part 3 / Leg, Ankle, and Foot Pain al.72 found the soleus m u c h more fatigue resis- tant than intrinsic hand and foot muscles. Its muscle is the forcefulness of plantar flex- contraction time was about 50% slower and its ion almost independent of knee angle. Be- half-relaxation time was 50% longer than that of cause of the 90° rotation of the Achilles either head of the gastrocnemius muscle.154 Van tendon64,96 and its attachment to the me- Hinsbergh et al.155 found that the soleus muscle dial one-third of the calcaneus (Fig. had the highest oxidative enzyme activity of all 22.7),96 the soleus also helps invert the the lower extremity muscles examined (gluteal, foot. quadriceps femoris, and gastrocnemius). Soleus muscle biopsy samples155 oxidized more palmi- Soleus tate and showed more cytochrome c oxidase ac- tivity per milligram of homogenate than did the Action other lower extremity muscles, probably be- cause of its higher percentage of type 1 (slow- The soleus muscle is a primary plantar flexor of twitch) fibers that depend on oxidative rather the \"free\" foot. Janda68 regards the soleus muscle than on glycolytic metabolism. as an assistant to supination of the foot. The degree to which the soleus is composed Although a number of authors have not rec- of fatigue-resistant slow-twitch fibers correlates ognized an inversion function of the with how the muscle is used. Nardone and soleus,29,71,123 a recent study by Michael and Schieppati101 found that, during lengthening Holder98 substantiated that the soleus muscle contractions of the triceps surae, the lateral selectively assists inversion of the foot. They head of the gastrocnemius was activated in sub- found in all of 28 dissections that the soleus jects with long soleus half-relaxation times portion of the Achilles tendon attached only to (more slow-twitch fibers), whereas the soleus the medial one-third of the calcaneus; hence, it was activated preferentially in subjects with would be expected to produce inversion of the short soleus half-relaxation times. heel. In all of the 10 subjects tested, stimula- tion of the medial part of the soleus muscle The responsiveness of the soleus muscle inter- produced plantar flexion and heel inversion, acts with conditions in other parts of the body. never eversion. The lateral portion of the mus- Hufschmidt and Sell87 stimulated the tibial nerve cle was not tested in this way.96 and interpreted changes in the latency of the si- lent period in the contralateral soleus muscle as in- The work of Campbell and associates,22 record- dicative of crossed motor reflexes in 17 of 30 sub- ing electromyographic (EMG) activity of the jects. soleus using fine-wire electrodes, established that there is no simple relation between inversion or Traccis and associates148 found that head rota- eversion of the foot and the motor unit activity of tion influenced the excitability of soleus motor medial or lateral portions of the muscle. Surpris- neurons as measured by the amplitude of Hoff- ingly, they found in untrained subjects that the man (H) reflexes. Response progressively in- medial part of the soleus was more active in foot creased with contralateral rotations from 0-16° eversion but, in trained subjects, the expected and progressively decreased with ipsilateral rota- EMG activity of the lateral part during eversion tions. was predominant. This difference may be due to athletic training enabling people to use their mus- Using the same H reflex measure, Romano and cles more efficiently.22 Schieppati129 showed that soleus motoneurone excitability increased during concentric (short- Comparing soleus and gastrocnemius activity ening) contractions of the soleus muscle and during ankle plantar flexion effort against varying that the more rapid the movement, the greater loads, Herman and Bragin61 reported that the the increase. Conversely, excitability was de- soleus EMG activity seemed to predominate in creased during eccentric (lengthening) contrac- minimal contractions, particularly in dorsiflexed tions to less than the control values observed positions. The slope of the relation comparing during rest, and the more rapid the movement, EMG activity and tension was nearly constant for the greater the reduction in excitability. Passive the soleus muscle regardless of its length. On the dorsiflexion of the foot contributed to H-reflex other hand, the gastrocnemius was most active inhibition. These modulations would help pre- electromyographically when the ankle was plan- vent overload of the soleus during sudden tar flexed, in strong contraction, and rapidly de- lengthening contractions. veloping tension. Soleus Contractile Properties The soleus muscle is remarkable among human muscles for its resistance to fatigue. Kukulka et
Chapter 22 / Soleus and Plantaris Muscles 437 Functions more than that of the gastrocnemius, but less than that of the vastus medialis and lateralis The soleus muscle is active during walk- muscles. The soleus was the only one of the ing, bicycling, running, and jumping. Its lower limb muscles monitored that increased pumping action increases the venous its activity when the pedal was shifted from flow of blood from the feet and legs. the instep to the toe position. An increase in pedalling rate increased soleus activity; an in- Surface electrode EMG studies of soleus func- crease in seat height did not. Among the 10 tion must be regarded with caution. Perry and as- subjects tested, the soleus muscle EMG activity sociates119 found that only 36% of the data ob- showed no significant difference in mean peak tained by soleus surface electrodes was related to amplitude between cycling and walking. activity of the soleus muscle. The bulk of the re- corded activity came from other muscles. Sports and Falls. Bilateral EMG activity of the soleus and lateral head of the gastrocnemius mus- Walking. Computer analysis of soleus muscle cle was recorded from surface electrodes with EMG activity among 25 normal individuals equal amplification during a single-foot volleyball walking at a variety of self-selected speeds iden- spike and a basketball layup. Activity was greatest tified 10 different patterns of EMG activity.134 on the dominant side and appeared more vigorous Activity always began either at or shortly before in the soleus than in the lateral head of the gas- heel-strike. As walking speed increased, it began trocnemius. Likewise, during right-handed sports earlier in the gait cycle. At higher walking activities, including overhand throws, underhand speeds, 5.3% of all patterns showed a second throws, tennis, golf, and hitting a baseball, the phase of soleus activity around toe-off, sug- right soleus was more active than the left and ap- gesting that some individuals were using the peared to be responding more vigorously than the soleus, at times, to help impart forward momen- gastrocnemius.20 tum. This study substantiated the marked varia- bility in the way normal individuals use their Greenwood and Hopkins59 recorded EMG activ- soleus muscles. ity in the soleus during sudden falls. When the fall was unexpected, two peaks of activity ap- Brandell16 found that, regardless of grade or peared. One was present immediately after loss of speed during walking, calf muscle activity rapidly support and appeared in muscles throughout the increased just before heel-rise and reached its body. No such initial soleus EMG activity was peak intensity at the transition from knee exten- found in two patients with absent labyrinthine sion to knee flexion as the ankle began to plantar function. The other peak appeared only in falls of flex. Yang and Winter161 found that the timing of sufficient height, exclusively in lower extremity the EMG activity was closely coupled to the per- muscles, and was related to the time of landing. centage of stride time that had elapsed, regardless The first peak was interpreted as a startle reaction of the cadence of walking. This is consistent with to an unexpected fall and the second to voluntary the previous conclusion that the primary role of preparation for landing. the triceps surae in walking is to stabilize (prevent further flexion of) the knee during the stance Venous Pump. As military people phase of gait.11,12 know well, raw recruits in the army who stand immobile at attention may Campbell and associates22 showed with fine- suddenly faint when venous blood wire electrodes that the medial and lateral por- pools in the lower limbs because it is tions of the soleus muscle can have distinctly dif- not being pumped upward by the soleus ferent functions in some subjects. The medial part muscle. Trained recruits rhythmically is a strong plantar flexor of the foot at the ankle, contract and relax the calf muscles iso- and a strong stabilizer of the leg on the foot. The metrically and thus avoid fainting while lateral part adds little power to moving the foot at they stand at attention. the ankle, but is largely a stabilizer, especially when the base of support is rendered unstable by The soleus provides a major pumping wearing high heels. action to return blood from the lower limb toward the heart. Venous sinuses in Bicycling. Ericson and associates38 recorded the soleus muscle are compressed by the EMG activity in each of 11 young men during muscle's strong contractions so that its ergometer cycling. The soleus muscle averaged venous blood is forced upward toward 37% of its maximum-effort EMG activity just the heart. This pumping action (the beyond the forward position of the pedal on body's second heart) depends on compe- the down stroke. This activation was slightly
438 Part 3 / Leg, Ankle, and Foot Pain artery to evaluate the pumping action of a motor- driven pedal that passively dorsiflexed the foot tent valves in the popliteal veins. Valves 15° and stretched the soleus muscle. Mean blood in the veins to prevent reflux of the blood flow increased progressively and doubled as the are most numerous in the veins of the pedal rate was increased from 24 to 50 cycles per lower limbs where the vessels must re- minute. turn blood against high hydrostatic pres- sure. The popliteal vein usually contains Frazier51 trained his surgical patients to plantar four valves.31 Deeper veins that are sub- flex the foot actively against a foam pad placed at ject to the pumping action of muscle con- the foot of the bed pre- and postoperatively. He traction are more richly provided with demonstrated radiographically with contrast me- valves.79 dium that this resisted isometric plantar flexion effort was remarkably more effective in emptying Ludbrook82 compared the soleus to other the veins within the soleus muscle than un- lower extremity muscles for its effectiveness as resisted plantar flexion. a musculovenous pump. On maximal contrac- tion, the soleus generated the most intramuscu- The value of electrical stimulation to contract lar pressure, 250 mm Hg, as compared to 230 the calf muscles under general anesthesia was re- mm Hg by the gastrocnemius and only 140 mm ported in 1972 by Nicolaides and associates.108 Hg and 60 mm Hg by the vastus lateralis and They found that a pulse duration of 50 ms at the an adductor muscle, respectively. A single con- rate of 1 2 - 1 5 pulses/min was optimal and effec- traction of the calf ejected about 60% of the tive in preventing deep vein thrombosis. blood that had entered it while standing, whereas thigh contraction ejected only about Since these studies were reported, the use of an- 20%. Ludbrook estimated that a single contrac- ticoagulants, such as heparin, have become popu- tion reduces the blood volume of the calf by lar to prevent venous thrombosis. In a recent 6 0 - 9 5 mL and of the thigh by 35 mL. The intra- study, the combination of heparin and electrical muscular sinuses that are so prominent in the activation of the tibialis anterior and gastrocne- calf are absent in the musculature of the thigh. mius-soleus muscles proved significantly more ef- An additional factor enhancing the soleus fective than heparin alone in preventing deep pump is the much greater competence of the vein thrombosis.95 valves in the popliteal veins in response to postural changes. The thigh veins refilled with \"Spontaneous\" thrombosis of the deep leg veins reflux of blood from above; the calf veins did can occur due to prolonged sitting when travel- not. ling in a car or airplane, especially in susceptible individuals.88 This can be prevented by activating Unlike most muscles, which show cessation of the soleus pump sufficiently often. The danger of arterial flow (133Xe clearance) at nearly 50% of sitting immobilized for prolonged periods in maximum voluntary contraction for only a brief chairs that produce underthigh compression was period, in two of four subjects,133 arterial flow con- demonstrated in air raid shelters by the frequency tinued in the soleus despite an 80% maximal con- with which pulmonary embolism followed imme- traction sustained for 2 minutes or until fatigue diately after air raids on London during World intervened. War II.137 McLachlin and McLachlin85 pioneered an un- Winkel and Bendix159 found that subjects who derstanding of the value of the soleus as a mus- were seated, either typing or doing desk work, ac- culovenous pump in clinical practice. They tivated the soleus muscle only occasionally and demonstrated by contrast venography the pool- then merely to 6% of maximum voluntary con- ing of blood in the soleus muscle in a relaxed traction. recumbent subject and the effectiveness of calf contraction in emptying the soleus venous sys- Postures. When an individual tries to stand qui- tem. Venography of six patients under anesthe- etly, a slight forward and backward sway devel- sia for surgery74 demonstrated that contrast dye ops that is controlled by alternate contraction of cleared the soleus muscle in one-third of the the anterior tibial and soleus muscles.11,70 When time when the patient was placed in the the person voluntarily tries to sway forward and Trendelenburg position (ankles placed 20 cm (8 backward either slowly or rapidly, the same pat- in) above heart level) as compared to clearance tern of muscle activity becomes very marked. The in the supine position.74 soleus is active while the center of gravity is ante- rior, and the anterior tibial muscle becomes active Sabri and co-workers132 surgically attached elec- tromagnetic flowmeters to the femoral vein and
Chapter 22 / Soleus and Plantaris Muscles 439 when the center of gravity swings posterior to the peroneus longus and brevis as plantar relaxed position.53, 109,110 Standing upright at mili- flexors, although if necessary, they can tary attention nearly doubles soleus activity, as learn to do so.63 compared with standing at ease. Standing with weight mainly on the balls of the feet activates the Antagonists to plantar flexion by the soleus muscle vigorously.109 Wearing high heels soleus muscle include primarily the tibi- usually increases the load on the soleus muscle.70 alis anterior, extensor digitorum longus, A high heel also causes ankle instability that re- and peroneus tertius muscles, which quires additional bursts of soleus activity to main- are assisted by the extensor hallucis tain equilibrium.22 longus.123 Specific and consistent stabilizing adjustments 6. SYMPTOMS (inhibition and excitation) appear in the lower limbs preparatory to vigorous movement of an up- This section first summarizes the symp- per extremity in standing subjects.16 Repeated toms that patients experience as a result tests of 11 subjects established that the soleus of soleus and plantaris TrPs. Then it ad- muscle was the first muscle to show EMG changes dresses major differential diagnostic con- in this situation. cerns, and finally it summarizes postex- ercise muscle soreness (covered in detail Resect/on of Soleus. Markhede and Nistor83 in the Appendix of this volume) and con- studied seven patients in whom part or all of the siders how shin splints may relate to soleus muscle had been removed surgically. All myofascial TrPs. seven patients could stand and walk on tiptoe. The only two patients reporting unsteadiness of Symptoms due to Trigger Points gait when walking on uneven ground were the two who had either the left or right half of all calf Soleus musculature removed. Just the soleus muscle was completely removed in three patients. Only one of An active TrP1 is, by far, the most com- the seven patients had a mean isometric plantar mon of the soleus TrPs. Patients with this flexion strength less than 80% of the normal side TrP complain of tenderness referred to and that was the one who had lost all of the soleus the heel in addition to pain in the distri- and half of the gastrocnemius muscle. bution described in Section 1 of this chapter. It may hurt unbearably to place Plantaris weight on the heel. The heel may ache at night. However, nocturnal calf pain is The plantaris weakly assists the gastroc- more likely to be caused by gastrocne- nemius muscle in flexion of the knee and mius than soleus TrPs. One of the most plantar flexion of the foot at the an- frequent complaints by recreational run- kle.12,29,64,123 Basmajian12 found, using fine- ners is heel pain.15 wire electrodes, that its primary action is plantar flexion and inversion of the foot. An active TrP2 or TrP3 causes pain re- Only in a loading situation does the plan- ferred in the patterns described in Section taris assist in knee flexion.12 1 of this chapter. These upper soleus TrPs are more likely to interfere with the 5. FUNCTIONAL (MYOTATIC) UNIT soleus musculovenous pump, causing symptoms of calf and foot pain together Together, the soleus and gastrocnemius with edema of the foot and ankle. muscles (triceps surae) are the prime plantar flexors of the foot. This function Soleus TrPs restrict ankle dorsiflexion. of the triceps surae is assisted by the per- This limitation makes it difficult or im- oneus longus and brevis, flexor hallucis possible for many patients to pick things longus, flexor digitorum longus, tibialis up from the floor by employing safe body posterior,68,1 2 3 and by the plantaris mus- mechanics to keep the trunk erect, which cle.123 Compared to all of these muscles requires knee flexion and unrestricted an- (except the relatively insignificant planta- kle dorsiflexion. Individuals with soleus ris), the triceps surae has a marked TrPs are prone to develop low back pain mechanical advantage due to the longer because the restriction of ankle dorsiflex- lever arm created by its calcaneal attach- ion leads them to lean over and lift im- ment. Many individuals do not use the properly.
440 Part 3 / Leg, Ankle, and Foot Pain A person with a very active soleus TrP and T2 relaxation times of the mass are can be severely immobilized. Walking be- the same as in neighboring muscles. comes difficult and painful, especially walking uphill, or up and down stairs. The diagnosis was sometimes made Some patients complain of low back pain when normal muscle tissue was found on when getting up from a chair without the biopsy or at operation.33 Several au- assistance of armrests. thors35,54 established the muscular nature of the mass when they recorded normal \"Growing pains\" were studied in 54 motor units by needle electromyography. children between the ages of 5 and 14 They and Graham58 observed the same years.14 One of the four stretch techniques motor latency as for the soleus muscle in used to provide lasting relief of the symp- response to tibial nerve stimulation. toms was a stretch specifically for the Other authors reported the use of xer- soleus muscle. This beneficial result sug- oradiography61,53 and sonography102 to gests that active soleus TrPs may have help establish the diagnosis. been a contributing cause of \"growing pains\" in these children, which matches Pain due to an accessory soleus muscle our experience and that of Bates and was relieved by total or subtotal resection Grunwaldt.13 of the muscle,8,0 1 0 2 , 1 0 7 , 1 3 0 , 1 5 3 by fasci- otomy,80,1 1 3 ,1 3 0 and by reattaching the ac- Accessory Soleus cessory tendon from the calcaneus to the Achilles tendon.81 Painful accessory A 1986 review130 found this variant re- soleus muscles were generally described ported in only 15 patients, suggesting that as tender. The painfulness of some of symptoms caused by an accessory soleus these accessory muscles may have been muscle occur rarely. caused by TrPs. No reports were found that specifically examined the muscle for Physical examination reveals a firm them. Since fasciotomy was repeatedly mass between the medial malleolus and successful, some of the painful muscles the Achilles tendon. The mass may or may may have suffered from a compartment not be tender. Traction on the muscular syndrome, but no intramuscular pressure mass plantar flexes the foot.6 The mass be- measurements were mentioned. comes hard (tense) when the foot is force- fully actively plantar flexed,42, 1 3 0 , 1 5 3 or Plantaris when standing on tiptoe.58 The mass ap- pears more prominent when the foot is An active TrP in the plantaris muscle re- dorsiflexed, which causes the accessory fers pain to the back of the knee and up- muscle to bulge out from between the per calf, as illustrated in Figure 22.3. Achilles tendon and the distal tibia. Differential Diagnosis If pain develops, it is located in the re- gion of the accessory muscle belly poste- Differential diagnoses to be considered in rior to the medial malleolus. The pain fre- patients with pain in a distribution char- quently starts after a conditioning pro- acteristic of common soleus TrPs include gram that requires running, and then is TrP syndromes of other muscles, rupture aggravated by running or just by walking. of a calf muscle, S1 radiculopathy, Achil- les tendinitis, thrombophlebitis, a rup- Diagnostic testing can help distinguish tured popliteal cyst, or possibly a sys- an accessory soleus muscle from a neo- temic viral infection. Patients with pe- plasm. Plain soft tissue radiography ripheral occlusive arterial disease and shows the extent of the mass,8,58, 130 but intermittent claudication often also de- does not confirm that it is muscle. A com- velop myofascial TrPs in the ischemic puterized tomography scan more clearly muscles. These TrPs can contribute sig- delineates the mass and can confirm that nificantly to the patient's pain.7 its density is similar to that of mus- cle.35,102,120,130 However, Pettersson et a l . 1 2 0 Other Trigger Points emphasize that uncertainty as to whether the mass is muscle or not can be resolved Another myofascial TrP source of heel if, on magnetic resonance imaging, the T1 pain and tenderness is the quadratus
Chapter 22 / Soleus and Plantaris Muscles 441 plantae muscle of the sole of the foot (see to cause ecchymosis that appears a day or Fig. 27.1). The tenderness caused by TrPs two later in the region of the lower calf in the quadratus plantae muscle is lo- and ankle. Ultrasonography, magnetic cated in front of the heel and can be elic- resonance imaging, and computed tomog- ited by pressing on the medial side of this raphy scans can identify the source of the muscle and backward toward the heel symptoms and extent of injury if these are deep in the instep. Myofascial TrPs in not apparent from careful palpation of the this muscle, like those in the soleus, also muscles and from the location of tender- cause the bottom of the heel to be hyper- ness. sensitive and the patient complains that it hurts to bear weight on the heel. Heel Spur Abductor hallucis TrPs also refer pain If the patient happens to have a bone spur to the heel, but to its medial side only on the plantar surface of the calcaneus, (see Fig. 26.2). the spur is frequently thought to be the cause of heel tenderness. However, if one Rupture looks at a radiograph of the other heel, it, too, may show an equally large spur that The plantaris muscle belly lies between is symptom free. The heel spur in such a the two heads of the gastrocnemius mus- patient is usually coincidental and has no cle in the popliteal space and its tendon causal relation to the pain or tenderness. passes distally between the soleus and A soleus muscle TrP1 is often a major gastrocnemius muscles. It is important to source of tenderness referred to the heel. distinguish between rupture of the plan- As pointed out by Singer,139 an elevated taris muscle or tendon, which is tempo- serum uric acid level may render a heel rarily painful but does not impair the spur painful, and is likely to aggravate power of plantar flexion, and rupture of TrPs in the soleus (and many other mus- the soleus muscle, which can cause plan- cles). tar flexion weakness. Other causes of heel pain include plan- The same stresses are likely to cause tar fasciitis, Achilles tendinitis, calcaneal rupture of either the plantaris or soleus stress fractures, entrapment of the calca- muscles. However, the plantaris muscle is neal branch of the posterior tibial nerve, more likely to be torn during a forceful and a fat pad syndrome.15 lengthening contraction with the knee straight; the soleus is more vulnerable Achilles Tendinitis when the knee is bent to some degree and is not protected by the gastrocnemius. Some cases of Achilles tendinitis, or peri- Plantaris muscle rupture causes a sudden sharp pain at the moment of tearing and tendinitis, may be due to shortening of the soleus may produce a snapping sound with a sense of injury in the calf. The patient and gastrocnemius muscles caused by TrPs in may describe an overload lengthening contraction caused by a fall, near-fall, or those muscles with chronically increased tension one caused by slipping while walking up a steep hill. Plantaris muscle rupture im- on the Achilles tendon. Patients with tendinitis mediately produces acute pain up and down the center of the calf followed later are likely to complain of diffuse pain in or about by ecchymosis as low as the ankle. the Achilles tendon that is aggravated by activ- Plantaris rupture should also be distin- guished from a tear of the gastrocnemius ity.25 Runners experience burning pain early in muscle (\"Tennis leg,\" see Chapter 2 1 , page 407), which is now thought to be the run which eases off during the run, but then more common than rupture of the planta- ris tendon.52 A rupture of the belly of the worsens afterward.19 Tenderness is most severe 4- gastrocnemius muscle (usually medial 5 cm (11/2-2 in) proximal to the tendon attachment head) is palpable near its distal mus- culotendinous junction and is also likely on the calcaneus, but may be diffuse along the en- tire Achilles tendon. When tendinitis is severe, swelling, crepitus, and a tender nodule in the ten- don may be present.19 Sonography can demon- strate thickening of the peritendinous connective tissue, and structural disturbance of the tendon including rupture with hematoma.97 In a study of 109 runners with Achilles tendini- tis, Clement and associates25 found the most com- mon cause to be overtraining or injudicious train- ing. Nearly half of their cases showed gastrocne-
442 Part 3 / Leg, Ankle, and Foot Pain mius/soleus weakness and loss of flexibility, both Popliteal (Baker's) Cyst of which are also caused by myofascial TrPs in these muscles. Excessive training is also likely to The effusion within the knee joint of a popliteal activate myofascial TrPs, a cause of pain which (Baker's) cyst greatly increases intra-articular was apparently not considered in this study. An- pressure when the knee is flexed. This pressure other common cause of Achilles tendinitis, func- can cause a cystic enlargement of the articular tional overpronation, is well illustrated and de- capsule posteriorly, or enlargement of the gastroc- scribed by these authors and can be corrected nemius-semimembranous bursa if it communi- with shoe inserts. One easily correctable cause of cates with the knee joint. (This communication is tendinitis, footwear with an inflexible sole, over- seen in about half of cadaver specimens.55) Effu- loads and may activate TrPs in the soleus muscle. sion producing a popliteal cyst is likely to occur in patients with arthritis (especially rheumatoid If the pain and tenderness are referred to the arthritis) of the knee and with internal derange- tendon by an active soleus TrP, they can be distin- ments of the knee joint (especially tears of the guished from the symptoms of tendinitis. Inacti- posterior aspect of the medial meniscus).100 An vation of the soleus TrP relieves the pain and ten- unruptured popliteal cyst may extend down the derness immediately if these symptoms are re- leg deep to the gastrocnemius muscle nearly to the ferred and not due to tendinitis. ankle, and it may be asymptomatic or may cause pain and swelling.55 When the patient stands with Posterior heel pain of the Haglund Syndrome is knees straight, the visible mass in the popliteal associated with a visible and palpable \"pump- space may be fluctuant on palpation. bump.\"112 In this syndrome, there is a thickening of the soft tissues at the insertion of the Achilles A Baker's cyst may cause sufficient pressure, tendon. It is seen in those who wear stiff shoes pain, and tenderness to be readily confused with with a shallow heel while engaging in strenuous thrombophlebitis or with soleus TrPs.55 The pain activity; it is characterized by a radiographically and swelling of the cyst tend to be more medial in prominent calcaneal enlargement at the insertion the calf, whereas thrombophlebitis pain is more of the Achilles tendon, retrocalcaneal bursitis, frequently lateral. When an enlarging cyst dissects thickening of the Achilles tendon, and a convex- soft tissue, bleeding may cause a crescent-shaped ity of the superficial soft tissues at the level of the ecchymotic area around the malleoli, the so-called Achilles tendon insertion. The degree of enlarge- \"crescent sign.\"55 Rupture of a cyst can cause ment is measurable by radiography.112 acute pain, tenderness, heat, and erythema strongly suggestive of thrombophlebitis.55,100 Thrombophlebitis Thrombophlebitis and Baker's cyst may occur at The calf tenderness of deep vein thrombosis, par- the same time.55,57,121 The distinction is important, ticularly of veins within the soleus muscle, could since their management is vastly different. mimic an acute myofascial syndrome. In thrombo- Thrombophlebitis requires anticoagulation ther- phlebitis, the relatively constant pain regardless apy. A ruptured Baker's cyst is treated with eleva- of muscular activity, and the presence of warmth tion of the leg and bed rest.55 A Baker's cyst is reli- and redness, are helpful in the diagnosis. How- ably diagnosed by ultrasonography.58 Arthrogra- ever, these signs may be absent, and clinical ex- phy reveals the popliteal cyst and demonstrates amination alone is unreliable for detection of its rupture. thrombophlebitis.124 Diagnostic techniques in- clude Doppler ultrasonography,\" impedance Postexercise Muscle Soreness plethysmography, and fibrinogen uptake.17,124 None of these is satisfactory for a definitive diag- Delayed-onset muscle soreness, which nosis, so contrast venography remains the stan- appears a day or two following unaccus- dard.122,124 tomed exercise that demands lengthening contractions, and which clears up in a Treatment of acute thrombophlebitis usually in- week or so, is not a myofascial TrP phe- cludes anticoagulant medication and bed rest. If nomenon. It has features that suggest the the patient has active TrPs in the soleus (or other soreness may be related in some ways to lower-limb muscles), the immobility of bed rest myofascial TrPs. A comprehensive re- will likely aggravate them. When assessing clini- view of a large amount of experimental cal progress, it is important to distinguish the pain data reported on the topic of delayed-on- and tenderness of thrombophlebitis from that of set muscle soreness appears in the Ap- TrPs. There are no convincing data that strict bed pendix of this volume for those who are rest is necessary or even desirable for patients interested in understanding more about it with thrombophlebitis.138
Chapter 22 / Soleus and Plantaris Muscles 443 and its possible relation to myofascial The reason why some athletes develop this TrPs. problem and others do not has not been estab- lished. The prevalence of soleus TrPs among pa- Shin Splints tients with stress fractures is unknown. TrPs in the medial portion of the muscle could account The term shin splints is used to describe for the focal decompensation of the osteoblastic pain in the anterior or medial leg associ- repair process where the taut band could impose ated with exercise. This pain is now rec- chronic tension on its bony attachment site. ognized to have a number of specific causes that should be distinguished from Soleus Syndrome (Periostalgia, Medial Tibial Stress referred pain caused by myofascial TrPs. Syndrome) The topic is reviewed here. Similar stress reactions are fully summarized for the ad- The pain of the soleus periostalgia syndrome is ductor muscles on page 301 of this vol- likely to occur during repetitive rhythmic exer- ume. cise, such as aerobic dancing or running. Initially, mild pain develops during the later stages of exer- In the past, the term \"shin splint\" de- cise and is relieved by rest. Successive episodes of noted any chronic exercise-related leg pain progressively increase in intensity, occur ear- pain. In recent years, it has acquired a lier during exercise, and may persist after exer- much more specific meaning: periostalgia cise.99 along the line of attachment of a repeatedly overloaded muscle. In 1985, Michael and Holder96 attributed shin splints of the medial tibia to stress overload of the Used in the general sense, shin splints mani- attachments of the soleus muscle (medial tibial fested by chronic pain and tenderness in the ante- stress syndrome69). A year later, Detmer34 showed rior portion of the leg often represent an anterior histologically that the medial tibial stress syn- compartment syndrome (discussed in Chapter drome (soleus syndrome) was caused by loosen- 19). Shin splints in the medial regions of the leg ing and sometimes separation of the periosteum are usually caused by one of three identifiable from the tibial cortex. He attributed this to rupture conditions, or some combination of them: (a) of Sharpey's fibers that extend from muscle stress fractures of the tibia; (b) chronic periostalgia through periosteum into the cortical bone struc- (the soleus syndrome, also called the medial tibial ture. For these reasons, he called this condition stress syndrome); and (c) a deep posterior com- chronic periostalgia. partment syndrome. (As noted previously, some authors now reserve the term shin splints exclu- On examination, the distal one-third to one-half sively for periostalgia.) The anatomical, diagnos- tic, and therapeutic distinctions among these of the medial side of the tibia is exquisitely three conditions were well described and illus- trated by Detmer34 under the term medial tibial tender; this is also the site of the pain. This ten- stress syndrome. The differential diagnosis and treatment of shin splints were recently reviewed derness is parallel and slightly posterior to the lo- by Brown and Braly.21 cation of tibial stress fractures.34 The lesions dem- Stress Fracture onstrated by the third phase of three-phase radio- The stress fracture and its pain and tenderness oc- cur along the medial aspect of the lower third of nuclide studies were longitudinally oriented, the tibia, solely in the bone; it may be focal or a band of varying length of microfracture where the often involving a third of the length of the tibia, fused fascial coverings of the soleus muscle attach to the tibia.34,131 Athletes with stress fractures are and usually showed varying intensity of tracer ac- unable to \"run through\" the pain.62 tivity along their length.62 This radiographic tech- Radionuclide scan reveals this fracture within a few days. Radiographic changes may not appear nique is now established as a reliable and prompt until weeks later. Radionuclide scans may image the fracture for as long as 10 months.131 Patients way of identifying periostalgia (the soleus syn- with stress fractures require 6 - 1 0 weeks of rest from sports activities followed by a gradual recon- drome) and of distinguishing it from stress frac- ditioning program.34 tures 62,77,96,99,11,131,156 The strong relation of periostalgic shin splints to the kind and amount of exercise, and the local- ization of pain and tenderness to the insertion of the overstressed muscle, distinguish this condi- tion clinically from myofascial TrP syndromes. Compartment Syndrome Although anterior compartment syndromes are recognized more often than posterior compart- ment syndromes,158 the two posterior compart- ments are of special interest in this chapter. The superficial posterior compartment contains the
444 Part 3 / Leg, Ankle, and Foot Pain soleus and gastrocnemius muscle bellies. The the soleus muscles if the person proceeds deep posterior compartment encloses the flexor at more than a slow pace. digitorum longus, flexor hallucis longus, popli- teus, and posterior tibial muscle bellies.103 Com- A common complaint of joggers is heel partment syndromes of the leg are also discussed pain,15 which often represents referred in Chapters 19, 20, and 23. tenderness from soleus TrPs. These TrPs are more likely to be activated when the Compartment syndromes of the leg are usually jogger lands on the forefoot with the induced by exercise and are of gradual onset. soleus shortened, which induces a vigor- They produce a sense of tightness and dull aching ous eccentric contraction [see Appendix of the involved muscles. As the condition intensi- to this volume). The soleus muscle is also fies, pain persists for longer periods following ex- vulnerable to overload when an individ- ercise. Posterior compartment syndromes are ual is skiing or ice skating without ade- commonly bilateral, usually fail to respond to quate ankle support. conservative therapy, and often require fasci- otomy.158 On examination, tenderness is not lo- Prolonged unaccustomed activity, such cated along the tibia laterally but is located in the as playing shuffleboard during a vacation muscle tissue itself, deep in the calf. The diagno- or hiking up a long steep hill, can over- sis of superficial posterior compartment syn- load the soleus muscle sufficiently to in- drome is confirmed by finding an elevated pres- duce TrPs in it. sure within the soleus muscle.34,60,158 The soleus and other muscles that cross The precise etiology of the posterior compart- the ankle region can be overloaded when ment syndromes is not yet established.34 An initi- an individual walks along the beach or on ating trauma or hypertrophy of the muscle has other laterally slanted surfaces. Muscles been postulated.158 The role of TrPs as part of this on either side may become overloaded, process is unknown, but there is a strong possibil- depending on how each individual uses ity that, in muscles prone to developing a com- these muscles to compensate for the slant. partment syndrome, TrPs may make a significant In most cases, the soleus on the down- contribution. ward side (comparable to a shorter lower limb) must work harder. This situation is 7. ACTIVATION AND PERPETUATION aggravated if that is also the side of an un- OF TRIGGER POINTS corrected shorter lower limb. Activation of Trigger Points A somewhat similar overload occurs when an individual wears inflexible The mechanical stresses that activate shoes with rigid soles that allow only an- TrPs in the soleus muscle include kle and no toe movement. The stiff sole overuse caused by the foot slipping at toe- greatly increases the lever arm against off and overloading the muscle, espe- which the soleus must work. Shoes must cially during forceful quick lengthening be examined specifically for flexibility of contractions. Additional stresses include the sole. direct trauma to the muscle, development of satellite TrPs in the muscle, and chil- Other Causes ling of the muscle. When a lower limb- length inequality is present, soleus TrPs Slipping or losing balance in a situation are more likely to be activated and perpet- that requires an unexpectedly vigorous uated in the shorter limb, toward which lengthening contraction of the soleus the body weight is shifted. muscle59 can activate TrPs in the muscle. An example is that of a foot unexpectedly Muscle Overload slipping on the stairs, throwing the entire body weight and recovery efforts on the Individuals wearing shoes with smooth other (weight-bearing) soleus muscle, par- leather soles while walking on a hard ticularly when only the forefoot of that slippery surface, such as wet pavement, limb is on the step. waxed tile, or marble floor, usually expe- rience slipping of the forefoot on push- Sustained pressure on the soleus can off. This slippage imposes an overload on initiate TrPs in it. In one case, a woman had been standing on the steps of a crowded bus, facing the door, for nearly an hour with her soleus muscle pressed
Chapter 22 / Soleus and Plantaris Muscles 445 against the next higher step to maintain Compromise of circulation by compres- her balance. The painful, tender heel that sion of the calf can perpetuate soleus resulted had been treated with injection TrPs. Resting the weight of the calf on the of a steroid into the Achilles tendon with- high edge of an ottoman, or on the foot- out relief of pain, and with partial rupture rest of some dental chairs, directly com- of the tendon. Examination of the soleus presses the soleus muscle causing local muscle revealed multiple active TrPs. In- ischemia, which aggravates TrPs. Sitting activating them by local procaine injec- on a chair seat that is too high for the feet tion relieved her heel pain and tender- to reach the floor fully usually causes a ness. degree of underthigh compression of the neurovascular trunk. If the seat has a high Myofascial TrPs of the soleus muscle front edge, and especially if the seat is can develop as satellites to primary TrPs pitched backward (lower behind than in in the posterior part of the gluteus mini- front), blood flow to the soleus muscle mus muscle, which often refer pain into can be compromised. Underthigh com- the calf in the region of the soleus. pression should be avoided. Tight elastic at the top of a sock below the knee can act Prolonged cooling of tired, immobile like a tourniquet, limiting blood flow in legs, as by an air conditioner in a car on a the calf muscles. Arcangeli and coau- long trip on a hot day, can activate soleus thors7 found that the occurrence of myal- TrPs. It is important to take frequent gic spots (TrPs) and the severity of limb breaks and walk around for a few minutes ischemia were often parallel in patients when on a long auto trip. with peripheral vascular disease. Perpetuation of Trigger Points 8. PATIENT EXAMINATION In addition to the systemic factors that Figs. 22.8 and 22.9 perpetuate TrPs, which are covered in Chapter 4 of Volume l , 1 5 2 several mechan- The soleus muscle should be tested for ical factors can perpetuate soleus TrPs. the Achilles tendon reflex (ankle jerk) Three common ones are keeping the mus- and for range of ankle dorsiflexion. This cle in the shortened position for a pro- response to the calcaneal tendon tap is longed period, chronic overuse, and com- best examined with the patient kneeling pression ischemia of the muscle. on a chair seat (Fig. 22.8). Flexing the knee to 90° in this way isolates the soleus The soleus muscles are obviously response by slackening the gastrocnemius placed in a shortened position when one at the knee joint and reducing its re- wears high heels. No treatment for active sponse. To ensure maximum relaxation, soleus TrPs is likely to provide lasting re- the patient should be positioned with the lief as long as the individual continues to torso erect and stabilized by holding onto wear high heels regularly. The same effect the backrest of the chair. The patient as wearing a high heel can be produced should also be encouraged to breathe nat- unilaterally when a thick heel lift is urally and to feel comfortable and re- placed inside the heel of one shoe to cor- laxed. This test is performed with the pa- rect a lower limb-length discrepancy. tient in this position because the ampli- tude of the Achilles tendon reflex is likely During sitting, sustained plantar flex- to be reduced if the patient lies in the ion is produced if the chair seat is too prone position with the knees straight; it high for the heels to rest firmly flat on the is also likely to be reduced if the patient floor. Prolonged soleus shortening results has a sensory neuropathy from a vitamin during sleep if the ankles are allowed to B1 (thiamine) inadequacy, diabetic neu- remain immobilized in the strongly plan- ropathy, or other neurological impair- tar flexed position at night. This position ment. can activate latent soleus TrPs. With a moderately active TrP in the Any of the postural situations de- soleus muscle, the ankle jerk is usually scribed previously that are capable of ac- reduced in amplitude and may fatigue af- tivating TrPs in the soleus muscle can ter six or eight taps. When there is more perpetuate them as long as the situation remains uncorrected.
446 Part 3 / Leg, Ankle, and Foot Pain Figure 22.8. Optimal position, kneeling on a chair seat, for tapping the Achilles tendon to test the tendon reflex (ankle jerk) of the soleus muscle, and for com- paring the response bilaterally. Figure 22.9. Testing the right soleus muscle for proaches the full normal dorsiflexion range. The arrow range of motion at the ankle with the knee flexed to shows the downward direction of pressure. 90°, patient prone. The dotted outline of the foot ap- marked TrP activity, the reflex may be but the less vigorous is the Achilles ten- nearly or completely inhibited. In such a don tap response. Following inactiva- case, intermittent cold with stretch may tion of the responsible soleus TrPs, the be applied to the soleus muscle while the local twitch response (that is restricted patient kneels on the chair seat. to the muscle fibers associated with taut bands) disappears and the Achilles ten- A blow of the percussion hammer on don tap response (of the entire muscle) the belly of the soleus muscle directly on returns at once. a TrP distal to the gastrocnemius muscle produces a soleus local twitch response When TrPs in the soleus muscle refer and an ankle movement that is not a pain proximally to the region of the poste- tendon tap response. Tapping a soleus rior superior iliac spine, exploration of muscle belly that is free of TrPs does that referral area by palpation reveals a not elicit this twitch response. The very sore, but circumscribed tender re- more active the soleus TrP, the more gion corresponding to the area of pain vigorous is the local twitch response, complaint.
Chapter 22 / Soleus and Plantaris Muscles 447 Figure 22.10. Palpation for trigger points in the right jerks bilaterally while the patient kneels on a chair seat. B, pincer palpation of TrP3, patient recumbent, soleus muscle. The ankle is in the neutral position. A, lying on the right side. initial flat palpation of TrP1 after testing the ankle A convenient screening test of soleus than because of TrPs in the gastrocnemius range of motion is the ability to squat muscle. with the heels flat on the floor. Patients with active soleus TrPs are either unable Active TrPs in the soleus that cause to squat at all or to do so only on the shortening of the muscle can lead to the toes.75 This test can be damaging to the false conclusion that the lower limb on knee ligaments if the knee is flexed too that side is longer than the other limb acutely while weight bearing. For manual when the patient bears body weight on testing of the soleus range of motion (Fig. the toes instead of the heel, holding the 22.9), the patient is best positioned lying heel off the floor slightly. prone witb the knee bent 90°. The range of ankle dorsiflexion is then tested by 9. TRIGGER POINT EXAMINATION pushing downward on the ball of the foot (Fig. 22.10) toward the examining table. Any TrP ten- sion of the soleus muscle restricts ankle All soleus TrPs can be examined by flat dorsiflexion, which should have a range palpation (Fig. 22.10A), and the distal of 20°. TrP1 and TrP3 also by pincer palpation from side to side deep to the tendo calca- Soleus weakness is tested by having the neus (Fig. 22.106). The kneeling position patient stand on the ball of one foot with is convenient for testing the ankle jerk, for adequate stabilization. During this test, a testing the local twitch response using the strong tendency for the foot to invert indi- percussion hammer, and for screening all cates substitution by the tibialis posterior three TrP locations by palpation (Fig. and/or the long flexors of the toes, 22.10A). whereas a strong tendency for it to evert indicates substitution by the peroneus When examining a recumbent patient longus and brevis muscles.71 These sub- for soleus TrPs (Fig. 22.10B), the knee is stitutions suggest soleus weakness. With flexed to slacken the gastrocnemius mus- normal triceps surae strength, the subject cle. should be able to jump at least 10 times on the ball of the foot without heel con- Soleus TrP1 is usually located approx- tact on the floor. imately 3 cm (11/4 in) below the end of the bulge that marks the lower border of The Lasegue test (straight-leg raising the gastrocnemius fibers, or about 14 cm with ankle dorsiflexion) is less likely to (51/2 in) above the heel. TrP3 is located produce calf pain because of soleus TrPs proximal and lateral to TrP1 close to the lower end of the gastrocnemius fibers (Fig. 22.1). These distal TrPs may also
448 Part 3 / Leg, Ankle, and Foot Pain be conveniently examined with the in- 10. ENTRAPMENTS volved leg of the side-lying patient placed on the examining table with the Soleus calf facing the examiner (Fig. 22.10B). The tenderness due to these distal Figures 22.5 and 22.6 illustrate the soleus soleus TrPs is localized deep to the apo- canal through which the posterior tibial neurosis of the Achilles tendon. Taut veins, posterior tibial artery, and tibial bands are located by holding the muscle nerve pass. Arkoff et al.8 noted during sur- between the fingers and thumb using gical exposure of the popliteal veins that, pincer palpation (Fig. 22.10B) and then when the leg was extended and the foot rolling the muscle between the digits. dorsiflexed, the vein was compressed as These taut bands and their TrPs are dif- it entered the soleus canal under the ten- ficult to locate unless the palpation is dinous arch. Mastaglia and associates84 done skillfully; they are easily missed. reported five cases of compression of the One must insert the fingers distal to the tibial nerve at the tendinous arch of the gastrocnemius muscle and posterior to soleus muscle. Three were simply entrap- the underlying tibia and fibula, lift up, ment of the tibial nerve by the arch and and examine the underside for TrPs by were relieved by surgical sectioning of rolling the muscle fibers under the fin- the arch. Although the histories of these gers, holding the thumb in place. Or, the patients were compatible with myofascial fingers can be kept in place and the TrPs of the soleus muscle, no mention thumb used for palpation. The medial was made of examination for TrPs. In one and lateral sides of the muscle may re- case, the nerve was entrapped by swelling quire separate examinations. If one is associated with thrombosis of a tributary considering injecting these TrPs, such of the popliteal vein. precise localization is necessary. Figure 22.5 shows a fibrous band of the Active TrPs in the proximal portion of soleus muscle which, when well devel- the muscle, the TrP2 area, are rarely oped, also has the potential for entrapping found in isolation; they usually occur in this popliteal neurovascular bundle. Ob- conjunction with the more distal TrPs in struction affects mainly the soft-walled the soleus muscle. With severe involve- veins, causing edema of the foot and ankle. ment, TrPs may be found also in other parts of the muscle. It is important to ex- The authors have seen several patients amine the proximal TrP2 by flat palpa- with compromised circulation of poste- tion against the underlying bone with rior tibial veins that was relieved by inac- the knee bent to about 90° in order to re- tivating TrPs deep in the soleus TrP3 re- lease tension in the gastrocnemius mus- gion. One patient had severe heel pain cle. This minimizes the likelihood of and tingling in the lateral portion of the mistaking a TrP in the overlying gastroc- foot suggestive of nerve entrapment; these nemius for a soleus TrP. Only a gastroc- symptoms, too, were relieved by inacti- nemius TrP should increase its sensitiv- vating a very irritable TrP2 in the soleus ity to palpation with a change in knee muscle. angle to greater extension. With the pa- tient in the kneeling position, additional Plantaris stretch may be applied to the soleus muscle by gently dorsiflexing the foot Taunton and Maxwell146 found occlusion with the band, assisted by the operator's of the popliteal artery by the plantaris knee, to increase sensitivity of the tendon in a 26-year-old female athlete soleus TrPs (Fig. 22.11A). who was limited to a walking distance of three blocks because of calf pain that had Taut bands in the plantaris muscle are been diagnosed as shin splints. After sec- not likely to be palpable and the spot ten- tioning of the plantaris tendon and en- derness of its TrPs is difficult to identify darterectomy with patch graft angi- because of the overlying thick lateral oplasty, she resumed full activity. head of the gastrocnemius muscle, which also may have TrPs. 11. ASSOCIATED TRIGGER POINTS Associated TrPs are most likely to occur in the gastrocnemius and posterior tibial
Chapter 22 / Soleus and Plantaris Muscles 449 Figure 22.11. Stretch position and intermittent cold cle. A, preliminary treatment while the patient is kneel- pattern (thin arrows) for trigger points in the right ing on a chair seat. Operator's knee assists by apply- soleus muscle. Thick arrows indicate the direction in ing pressure through the hand. B, more effective, re- which gradually increasing pressure is applied in order laxed position, patient lying prone. to dorsiflex the ankle, passively lengthening the mus- muscles and, not infrequently, in the long ment methods are reviewed on pages 9— flexors of the toes, all of which are ago- 10 of this volume. nists of the soleus. When there is exten- sive involvement of these plantar flexor Soleus muscles, their antagonists (the tibialis an- (Fig. 22.11) terior, extensor digitorum longus, per- oneus tertius, and extensor hallucis Intermittent Cold with Stretch longus) may also become involved. The ankle should be checked for restriction of During examination of the calf muscles plantar flexion and these anterior leg with the patient kneeling on a chair seat, muscles should be examined for TrPs. as illustrated in Figure 22.10A, one can also test the response of soleus TrPs to in- When the patient with an active soleus termittent cold with stretch (Fig. 22.11A). TrP complains of knee pain, a likely place For inactivation of less responsive TrPs, to look for TrPs is in the ipsilateral quad- this procedure is more effective with the riceps femoris muscle. Impairment of patient lying prone (Fig. 22.11B). In either soleus function places increased de- position, an initial sweep of ice or vapo- mands on the quadriceps femoris. coolant spray is applied distalward over the calf, heel, and instep. Then, during Since patients with soleus TrPs cannot parallel sweeps of the intermittent cold, squat comfortably, they usually lean over increasing pressure is exerted gently to to pick up an object from the floor and are dorsiflex the foot fully. This is always thus likely to overload their back muscles done with the knee flexed to release any and activate a new group of TrPs. tightness of the gastrocnemius that would block ankle dorsiflexion and prevent full 12. INTERMITTENT COLD WITH stretch of the soleus muscle. When soleus STRETCH TrPs refer pain to the sacroiliac region, (Fig. 22.11) that referral area should also be included as part of the intermittent cold pattern. The use of ice for applying intermittent cold with stretch is explained on page 9 With the patient recumbent, a moist of this volume and the use of vapocoolant heating pad or hot pack should be applied spray with stretch is detailed on pages to the calf at once after intermittent cold 67-74 of Volume l . 1 5 1 Techniques that with stretch, and then a few active pedal augment relaxation and stretch are re- movements are performed through plan- viewed on page 11 and alternative treat-
450 Part 3 / Leg, Ankle, and Foot Pain tar flexion and dorsiflexion to reestablish 3 seconds more of passive stretch, (c) Even more full active range of motion of the muscle. effective was a combined technique of contract-re- lax and antagonist contraction that improved the Other Modalities average range another 1.6°. The contract-relax method was assisted by active dorsiflexion effort Other stretch techniques and the applica- during the last 3 seconds of passive stretch. This tion of transcutaneous electrical nerve study shows the additive effects of static stretch, stimulation (TENS) have been found postisometric relaxation, and reciprocal inhibi- helpful in alleviating the pain caused by tion. soleus TrPS. The soleus/tibialis anterior pair of mus- Stretch Techniques. Lewit75 described cles presents a classic example of recipro- and illustrated the use of postisometric cal inhibition,32 which should be em- relaxation for releasing a tight soleus ployed liberally for release of soleus tight- muscle, using the positioning of Figure ness. 2 2 . U S . We find this postisometric relaxa- tion technique often effective when used Transcutaneous Electrical Nerve Stimulation alone and particularly effective when (TENS). Francini and coinvestigators50 measured used as a stretch component of intermit- pain threshold, amplitude of responses to Achil- tent cold with stretch. les tendon taps, and amplitude of H reflexes before, during, and after application of 50-Hz Evjenth and Hamberg41 describe and il- pulses of TENS stimulation. Responses were mea- lustrate soleus stretch in one limb for the sured on the stimulated and unstimulated sides in standing patient who leans forward 40 healthy subjects and in 25 patients with pain against a wall. Simultaneous knee flexion caused by TrPs in the triceps surae. The reported and ankle dorsiflexion are controlled by location of these TrPs at the junction of the triceps manual pressure of the clinician to stabi- surae and the Achilles tendon makes it likely that lize the heel on the floor with one hand the TrPs were located in the soleus, rather than in while applying pressure to the calf below the gastrocnemius muscle. These authors50 found the knee with the other. that, in the patients with pain, both facilitation and inhibition of the sensorimotor system during Moller and associates98 investigated the effect of and after TENS were more marked than in normal the sequence of contract-relax-stretch on dorsi- subjects. Also, in the patients with pain, the ini- flexion at the ankle with the knee bent (soleus tial pain threshold of the painful limb was either stretch) in eight normal subjects with no history of notably higher or lower than that of the other musculoskeletal disorder. This technique re- limb. This asymmetry was reduced by TENS. The quired maximal isometric contraction of the investigators concluded that TENS induced a nor- soleus muscle in the lengthened position for 4 - 6 malization of the sensory and muscular functions, seconds, then complete relaxation for at least 2 both of which outlasted the period of TENS appli- seconds, and passive dorsiflexion as far as possi- cation. Pain relief was concomitant with this reset ble without causing pain, with this lengthened effect of TENS. The authors gave no indication position maintained for eight seconds. This cycle that the TENS inactivated the TrPs, only that it was repeated five times. Immediately afterward, temporarily relieved the pain from them. dorsiflexion at the ankle had increased 18% and maintained an increase of more than 12% of the Plantaris prestretch range l'/2 hours later. One would ex- pect the gain in range of motion to be greater in Intermittent cold with stretch of the plan- muscles shortened by active TrPs than in normal taris muscle is performed as for the gas- muscles. trocnemius muscle (see Fig. 21.5), since these two muscles bave nearly identical A revealing study of soleus stretch by Etnyre attachments (Fig. 22.4). and Abraham39 employed three methods, each on separate days, in 12 subjects, (a) Static stretch In their description and illustration of a alone for 9 seconds with a force of 7.4 kg was inef- stretch technique for the plantaris mus- fective, (b) A contract-relax technique was signifi- cle, Evjenth and Hamberg40 apply the cantly more effective (p<0.001) and increased the same method used to stretch the medial range of motion 2.2°. In this method, passive head of the gastrocnemius muscle, since lengthening of the soleus was followed by isomet- ric plantar flexion for 6 seconds, then followed by
Chapter 22 / Soleus and Plantaris Muscles 451 Figure 22.12. Injection of trigger points in the right soleus muscle. A, medial ap- proach to the most common location, distal TrP1, with the patient lying on the same (right) side. B, lateral approach to the less common and most proximal TrP2. The patient is lying on the opposite side. Solid circle locates the fibular head. the tendon of the plantaris muscle at- be required for injection of soleus TrPs taches to the medial side of the Achilles when the calf muscles are unusually tendon. These authors press the heel large. against a lateral wedge to evert the heel while dorsiflexing the foot and keeping The distal soleus TrP1 is usually most the knee straight. accurately localized by pincer palpation from both sides of the muscle, anterior to 13. INJECTION AND STRETCH the Achilles tendon. For injection, TrP1 is (Fig. 22.12) easily approached from the medial side at the point of maximum tenderness, distal A full description of the procedure for to the bulge that marks the lower end of TrP injection and stretch of any muscle the gastrocnemius muscle fibers. The pa- appears in Volume 1, pages 7 4 - 8 6 . 1 5 1 For tient lies on the right side for injection of injection, the physician should wear the right soleus, with the uppermost (left) gloves. A solution of 0.5% procaine in leg in front of the involved one (Fig. isotonic saline is used for injection. 22.12A). The operator applies counter pressure to the tender spot with one fin- Soleus ger pressing directly on the TrP from the (Fig. 22.12) lateral side of the muscle, while the nee- dle is inserted on the medial side and Steroids are to be avoided when injecting aimed directly at the center of that finger. the distal part of this muscle because of Probing of the area may be necessary to the danger of causing rupture of the inactivate a cluster of TrPs. Achilles tendon. In many patients, a 37- mm (l1/2-in) 22-gauge needle is sufficient, To inject proximal TrP2, the patient lies but a 50-mm (2-in) 21-gauge needle may on the opposite side so that the soleus can be approached laterally. The needle is di-
452 Part 3 / Leg, Ankle, and Foot Pain Figure 22.13. Soleus Pedal Exercise for active A, first foot, full dorsiflexion; B, full plantar flexion; C, stretch of the soleus muscle and to enhance its vascu- pause and rest position; D, other foot, full dorsiflexion; lar pumping action. One foot completes a rhythmic cy- E, full plantar flexion, followed by a pause and rest as cle of full dorsiflexion, full plantar flexion, and a rest in C. pause. The other foot then completes a similar cycle. rected toward the fibula at the spot of needle should approach the TrP through maximum tenderness, which is encoun- the lateral head of the gastrocnemius to tered deep, close to the bone (Fig. avoid the popliteal neurovascular bundle 22.12B). in the midline (Figs. 22.3-22.5). Soleus TrP3 is injected with a technique 14. CORRECTIVE ACTIONS similar to that used for TrP1, except that it (Figs. 22.13-22.17) is approached from the lateral side. Corrective Posture and Activities Occasionally, a soleus TrP is located (Figs. 22.13-22.16) deep in the middle portion of the muscle. When the needle must penetrate deeply Active soleus TrPs often will not resolve near the midline of the muscle, one must if the soleus muscle remains shortened at consider the tibial nerve and posterior night. When a person sleeps either supine tibial veins and artery (Fig. 22.6). In this or prone, the feet usually are strongly case, it is better to start with a midline plantar flexed (see Fig. 21.11B); this may skin penetration of the needle and angle occur also when lying on the side. As il- the needle away from the neurovascular lustrated in Figure 21.11 A, a firm pillow bundle. or other support can be placed against the feet under the bed sheet to maintain a Postinjection soreness may be severe, neutral position at the ankles. Instead of so it is wise never to inject the soleus using a pillow, the bed can be positioned muscles in both legs at one visit. The pa- against a piece of furniture or wall at the tient is directed to use moist heat on the end of the bed to provide such foot sup- calf twice daily for several days during port, or for prone lying, the feet may be this period of soreness, to take acetami- allowed to hang down over the end of the nophen (Tylenol) for relief of pain, and to bed. avoid strenuous exercise or activities that may overload this muscle. The patient For those who sleep on the back, a may find it beneficial to wear long, loose small pillow under tbe knees may be wool socks to provide warmth for the calf helpful. Full extension of the knee tends by conserving body heat. to occlude the popliteal veins in some in- dividuals. However, too much knee and Plantaris hip flexion caused by a large pillow under the knees can result in undesirable A plantaris TrP, when present, is usually prolonged shortening of the knee and hip located between the two heads of the gas- flexors. trocnemius muscle and slightly lateral to the midline at the level of the tibial pla- For patients who are prone to chilli- teau. On examination, it appears similar ness, long loose socks worn at night to to a TrP in the popliteal portion of the cover the calves conserve body warmth gastrocnemius muscle. If it is injected, the and prevent cooling of the calf muscles.
Chapter 22 / Soleus and Plantaris Muscles 453 Figure 22.14 Correct and incorrect (red X) foot- formed regularly while a person sits for a rests. The arrows indicate excessive pressure. A, cor- prolonged period, as on a long airplane rect footrest distributes the weight of the lower limb trip. This active stretching exercise is exe- evenly on the sole, heel, and calf. It also holds the foot cuted in an alternating fashion: first, rais- in a neutral position at the ankle. B, incorrect footrest ing the toes and then the heel of one foot, with a domed shape compresses the calf muscles and and then after a pause raising the toes and obstructs their circulation. It also encourages plantar heel of the other foot (Fig. 22.13). This flexion of the foot and prolonged shortening of the calf pedal exercise also activates the \"soleus muscles. C, incorrect footrest with a soft center and a pump\" and improves the venous return hard edge compresses the neurovascular bundle in from the lower limbs. A half-dozen such the soleus canal and obstructs circulation in the gas- pedalling cycles should be performed at trocnemius and soleus muscles. It also favors plantar least every half hour when sitting. flexion at the ankle and shortening of these muscles. For anyone prone to syncope when An activity that helps reduce the irrita- standing still, activation of the soleus bility of TrPs in this muscle is the Soleus pump by alternately contracting the Pedal Exercise (Fig. 22.13). It can be per- soleus muscles, or by bearing weight on the toes alternately on right and left sides, helps prevent pooling of blood in the legs and can prevent syncope. Those who are prone to soleus TrPs and syn- cope should avoid tight garters or tight elastic cuffs on socks that can act like a tourniquet and compromise venous re- turn from the calf. Application of thin rubber half-soles to substitute for slippery leather shoe soles can help, especially if the patient with soleus TrP problems walks on hard, slip- pery floors. The shoes should be exam- ined for flexibility. The toe of the shoe should bend easily. If the sole is so rigid that it fails to bend fully during ambula- tion, the soleus is forced to work against an extended lever arm. This chronic over- load may cause the muscle to respond poorly to specific TrP treatment. Shoe traction and flexibility are impressively important to soleus function, and wearing proper shoes may be essential for lasting relief of calf and heel pain. When a chair seat is too high and only the toes reach the floor, either the chair seat must be lowered, or an adequate foot- rest must be provided. A cone-shaped footstool provides a variety of heights for different degrees of knee flexion and for supporting the ankle in a neutral posi- tion. High heels not only place the soleus in a chronically shortened position, but pro- vide an unstable base of support. In some patients, changing to low heels is a criti- cal factor in the recovery of the calf mus- cles from myofascial pain syndrome. The unilateral \"high heel\" effect of placing a heel lift in one shoe can be minimized if
454 Part 3 / Leg, Ankle, and Foot Pain Figure 22.15. Angled stair-climbing technique to re- soleus, paraspinal, and posterior hip muscles. Climb- lieve the soleus, gluteal, and paraspinal muscles of ing the stairs in this posture is analogous to leaning strain. A, correct way, approaching the stairs with the over a low sink. That posture also can markedly dor- body angled 45°, the torso held erect, and the weight- siflex the leading ankle, overloading the soleus in its lifting heel firmly supported. B, usual bent-forward fully lengthened position. posture, facing the steps, which tends to overload the Figure 22.16. Correct and incorrect solutions to the presses down on the left knee to divide the load and problem of safely bending down to pick up an object prevent back strain. B, correct way of returning to the on the floor when trigger points in the soleus muscle standing position with the feet and left arm in essen- restrict ankle dorsiflexion and prevent the commonly tially the same position as when reaching down to the recommended technique using knee flexion. A, correct floor. C, incorrect way of bending over and reaching to pick-up position. Bending down on one knee does not the floor to pick up an object. require full dorsiflexion of either ankle. The left hand part or all of the total correction is made the shoe has no heel to cut down, it may by cutting down the heel height of the be necessary to add a half-sole as well as a sboe worn on the longer limb. However, if heel lift on the shorter side.
Chapter 22 / Soleus and Plantaris Muscles 455 Figure 22.17. Standing self-spray and self-stretch positioning (red X) of the rear (right) foot on the side of technique for the right soleus muscle, bending the the muscle being sprayed and stretched. The right right knee to dorsiflex the right ankle passively. The lower limb is laterally rotated and the foot is turned heel of the stretched muscle must remain flat on the outward, which prevents full dorsiflexion at the ankle floor. The spray is applied in the same pattern of and thus lessens the stretch on the right soleus mus- downward sweeps over the muscle to the heel as in cle. Figure 22.11. A, correct position of feet. B, ineffective When driving on a long trip, one shows another type of ottoman that should make frequent stops and walk should be avoided. This demonstrates around for a few minutes to restore circu- how a soft-centered leg rest with a hard lation; cruise control also provides an op- edge can produce soleus compression. portunity to change positions. One solution is a slanted footrest that A common perpetuating cause of TrPs places the ankles at nearly 90° when the in the soleus muscle is an improperly feet rest on it (see Fig. 16.6C in the Ham- designed or improperly used leg rest that string chapter). With such a footrest, from causes calf compression. People who sit time to time the forefoot can be placed in reclining chairs with built-in leg rests against the footrest with the heels on the that concentrate weight on a portion of floor to provide additional ankle dorsi- the calf may require additional pillows or flexion (see Fig. 1 6 . 6 8 ) . may need to restrict elevation of the leg rest. If an ottoman is used for leg support, Soleus overload can be avoided by lim- it should be designed and arranged so iting walking in soft sand, unless the calf that part of the weight is carried by the muscles are conditioned for it, and by not heels. Figure 22.14A shows such a good walking long distances on a sidewalk or position with lower limb weight evenly beach slanted to one side. Lower limb- distributed and the ankles in a neutral po- length inequality should be corrected by sition. an appropriate lift (Chapter 4). Figure 22.146 demonstrates use of a Patients with active soleus TrPs often domed, firm ottoman that compresses calf experience pain when walking up stairs muscles and obstructs venous circulation. facing forward as usual (Fig. 22.158). The This should be avoided. Figure 22.14C problem is corrected by approaching the stairway with the body erect and angled
456 Part 3 / Leg, Ankle, and Foot Pain 45°, placing the entire foot flat on the step cold with stretch, or postisometric relaxa- above without markedly dorsiflexing it tion alone may be used. Lewit76 describes (Fig. 22.15A). This technique avoids pain- and illustrates a seated version of soleus ful strain and stretch of the soleus muscle self-stretch that employs postisometric re- by minimizing ankle plantar flexion and laxation. dorsiflexion. Keeping the body erect min- imizes strain on the back muscles and Patients with soleus TrPs are benefitted gives the strong quadriceps femoris mus- by first soaking in a tub of warm water or cle a larger share of the load. This angling taking a moderately hot shower, and then technique works equally well on a ladder. performing the soleus self-stretch. It can also be used when ascending a steep slope, by turning the body and feet A valuable exercise for the home pro- to one side and climbing sideways, or by gram is the Soleus Pedal Exercise de- following a zigzag course up the hill. scribed on page 453 (Fig. 22.13). When patients have active soleus TrPs, Stretching of the calf muscles is impor- painful restriction of dorsiflexion limits tant to athletes who participate in run- the ability to bend the knees and keep the ning sports, such as soccer and basket- back erect as recommended for picking an ball, yet it is surprisingly neglected in object up from the floor (see Volume 1, practice.73 Fig. 48.11). The individual should be taught to reach an object safely by kneel- References ing on one knee to avoid painful dorsi- flexion of either foot at the ankle (Fig. 1. Anderson JE: Grant's Atlas of Anatomy, Ed. 8. 22.16A and B). Williams & Wilkins, Baltimore, 1983 (Fig. 4- 72). Home Therapeutic Program (Fig. 22.17) 2. Ibid. (Fig. 4 - 8 1 ) . 3. Ibid. (Fig. 4 - 8 3 ) . The soleus is one muscle that can easily 4. Ibid. (Fig. 4 - 8 4 ) . be treated by the patients themselves us- 5. Ibid. (Fig. 4 - 9 8 ) . ing intermittent cold with stretch (Fig. 6. Apple JS, Martinez S, Khoury MB, et al.: Case 22.17A). The patient stands, keeping the involved knee bent to slacken the gastroc- report 376. Skel Radiol 1 5 : 3 9 8 - 4 0 0 , 1986. nemius muscle, and gradually transfers weight onto the posteriorly placed af- 7. Arcangeli P, Digiesi V, Ronchi O, Dorigo B, fected leg. With the knee straight, a tight Bartoli V: Mechanisms of ischemic pain in pe- gastrocnemius may block full passive ripheral occlusive arterial disease. In Advances stretch of the soleus. Support by the con- in Pain Research and Therapy, edited by J. J. tralateral arm is important for stability. Bonica and D. Albe-Fessard, Vol. I. Raven The foot of the leg being stretched must Press, New York, 1976 (pp. 965-973, see p. 966 point straight ahead. If the foot is allowed and Fig. 2). to turn outward, stretch on the soleus muscle is reduced (Fig. 22.17B). The pa- 8. Arkoff RS, Gilfillan RS, Burhenne HJ: A simple tient is taught to apply a safe vapocoolant method for lower extremity phlebography- spray downward over the calf in slow Pseudo-obstruction of the popliteal vein. Radi- parallel sweeps, starting with the muscle ology 9 0 : 6 6 - 6 9 , 1 9 6 8 . under comfortable tension. The muscle is gradually lengthened by further bending 9. Baker BA: Myofascial pain syndromes: ten sin- the knee, taking up the slack that devel- gle muscle cases. J Neurol Orthop Med Surg 10: ops as the soleus muscle tension releases. 129-131, 1989. For added stretch, a wedge can be placed under the heel laterally to evert the heel 10. Bardeen CR: The musculature, Sect. 5. In Mor- slightly while the foot is being dor- ris's Human Anatomy, edited by C M . Jackson, siflexed. Ed. 6. Blakiston's Son & Co., Philadelphia, 1921 (pp. 517, 523). Addition of postisometric relaxation augments the effectiveness of intermittent 11. Basmajian JV, Deluca CJ: Muscles Alive, Ed. 5. Williams & Wilkins, Baltimore, 1985 (pp. 2 5 6 - 257, 337-340, 370). 12. Ibid. (pp. 338, 3 4 5 - 3 4 7 ) . 13. Bates T, Grunwaldt E: Myofascial pain in childhood. J Pediatr 5 3 : 1 9 8 - 2 0 9 , 1958 (p. 202, Fig. 3). 14. Baxter MP, Dulberg C: \"Growing pains\" in childhood—a proposal for treatment. J Pediatr Orthop 8 : 4 0 2 - 4 0 6 , 1 9 8 8 . 15. Bazzoli AS, Pollina FS: Heel pain in recrea- tional runners. Phys Sportsmed 1 7 : 5 5 - 6 1 , 1 9 8 9 . 16. Bouisset S, Zattara M: A sequence of postural movements precedes voluntary movement. Neurosci Lett 2 2 : 2 6 3 - 2 7 0 , 1981. 17. Bradford JA, Lewis RJ, Giordano JM, et al.: De- tection of deep vein thrombosis with Doppler ultrasound techniques in patients undergoing
Chapter 22 / Soleus and Plantaris Muscles 457 total knee replacement. Orthopedics 5 : 3 0 5 - 3 0 8 , 4 3 . Ferner H, Staubesand J: Sobotta Atlas of Human Anatomy, Ed. 10, Vol. 2. Urban & Schwarzen- 1982. berg, Baltimore, 1983 (Fig. 380). 18. Brandell BR: Functional roles of the calf and 4 4 . Ibid. (Figs. 4 2 0 , 4 6 9 ) . vastus muscles in locomotion. Am J Phys Med 4 5 . Ibid. (Fig. 4 6 1 ) . 46. Ibid. (Fig. 4 6 4 ) . 56:59-74, 1977. 47. Ibid. (p. 4 6 5 ) . 19. Brody DM: Running injuries. Clin Symp 32:2- 4 8 . Ibid. (p. 4 7 1 ) . 4 9 . Ibid. (p. 4 7 2 ) . 36, 1980 (see p. 21). 50. Francini F, Maresca M, Procacci P, et al.: The 20. Broer MR, Houtz SJ: Patterns of Muscular Activity effects of non-painful transcutaneous electrical in Selected Sports Skills. Charles C Thomas, nerve stimulation on cutaneous pain threshold Springfield, 1967. and muscular reflexes in normal men and in 21. Brown MR, Braly WG: Differential diagnosis subjects with chronic pain. Pain 1 1 : 4 9 - 6 3 , and treatment of shin splints. Surg Rounds Orthop pp. 2 7 - 3 2 , Sept, 1989. 1981. 22. Campbell KM, Biggs, NL, Blanton PL, et al.: 51. Frazier CH: Improving venous flow and leg Electromyographic investigation of the relative muscle activity in postoperative patients: an experimental method. Orthop Rev 4:45—47, activity among four components of the triceps surae. Am J Phys Med 5 2 : 3 0 - 4 1 , 1 9 7 3 . 1975. 23. Carter BL, Morehead J, Wolpert SM, et al.: 52. Froimson Al: Tennis leg. JAMA 2 0 9 : 4 1 5 - 4 1 6 , Cross-Sectional Anatomy. Appleton-Century- 1969. Crofts, New York, 1977 (Sects. 68-80). 24. Ibid. (Sects. 7 1 - 8 0 ) . 53. Gantchev GN, Draganova N: Muscular syner- 25. Clement DB, Taunton JE, Smart GW: Achilles gies during different conditions of postural ac- tivity. Acta Physiol Pharmacol Bulg 7 2 : 5 8 - 6 5 , tendinitis and peritendinitis: etiology and treatment. Am J Sports Med 1 2 : 1 7 9 - 1 8 4 , 1 9 8 4 . 1986. 26. Clemente CD: Gray's Anatomy of the Human Body, American Ed. 30. Lea & Febiger, Phila- 54. Ger R, Sedlin E: The accessory soleus muscle. Clin Orthop 1 1 6 : 2 0 0 - 2 0 2 , 1 9 7 6 . delphia, 1985 (p. I l l , Fig. 3-16). 27. Ibid. (p. I l l , Fig. 3 - 4 7 ) . 55. Gordon GV: Baker's cyst and thrombophlebitis: 28. Ibid. (p. 112, Fig. 3 - 4 8 ) . a problem in differential diagnosis. Internal 29. Ibid. (pp. 5 7 6 - 5 7 7 ) . Medicine (Oct) 1 9 8 0 (pp. 3 9 - 4 5 ) . 30. Ibid. (p. 582, Fig. 6 - 7 9 ) . 31. Ibid. (pp. 850, 8 6 1 ) . 56. Gordon GV, Edell S: Ultrasonic evaluation of popliteal cysts. Arch Intern Med 7 4 0 : 1 4 5 3 - 1 4 5 5 , 32. Crone C, Nielsen J: Spinal mechanisms in man 1980. contributing to reciprocal inhibition during 57. Gordon GV, Edell S, Brogadir SP, et al.: Baker's voluntary dorsiflexion of the foot. J Physiol 416: cysts and true thrombophlebitis. Report of two 255-272, 1989. cases and review of the literature. Arch Intern Med 7 3 9 : 4 0 - 4 2 , 1 9 7 9 . 33. Danielsson L, Theander G: Supernumerary 58. Graham CE: Accessory soleus muscle. Med J soleus muscle. Acta Radiol Diagn 2 2 : 3 6 5 - 3 6 8 , Austral 2 : 5 7 4 - 5 7 6 , 1 9 8 0 . 1981. 59. Greenwood R, Hopkins A: Muscle responses during sudden falls in man. J Physiol 2 5 4 : 5 0 7 - 34. Detmer DE: Chronic shin splints. Classification 518, 1976. and management of medial tibial stress syn- drome. Sports Med 3 : 4 3 6 - 4 4 6 , 1986. 60. Henstorf JE, Olson S: Compartment syndrome: 35. Dokter G, Linclau LA: Case Report. The acces- pathophysiology, diagnosis, and treatment. Surg Rounds Orthop 3 3 - 4 1 , (Feb) 1 9 8 7 . sory soleus muscle: symptomatic soft tissue tu- mour or accidental finding. Neth J Surg 3 3 : 1 4 6 - 61. Herman R, Bragin J: Function of the gastrocne- mius and soleus muscles. Phys Ther 4 7 : 1 0 5 - 149, 1981. 113, 1967. 36. Edgerton VR, Smith JL, Simpson DR: Muscle 62. Holder LE, Michael RH: The specific scin- fibre type populations of human leg muscles. Histochem J 7 : 2 5 9 - 2 6 6 , 1975. tigraphic pattern of \"shin splints in the lower leg\": concise communication. J Nucl Med 2 5 : 37. Elder GCB, Bradbury K, Roberts R: Variability 865-869, 1984. of fiber type distributions within human mus- 63. Hollinshead WH: Functional Anatomy of the cles. J Appl Physiol 5 3 : 1 4 7 3 - 1 4 8 0 , 1982. 38. Ericson MO, Nisell R, Arborelius UP, ef al.: Limbs and Back, Ed. 4. W.B. Saunders, Philadel- Muscular activity during ergometer cycling. phia, 1976 (pp. 329-330). Scand J Rehabil Med 7 7 : 5 3 - 6 1 , 1 9 8 5 . 64. Hollinshead WH: Anatomy for Surgeons, Ed. 3., 39. Etnyre BR, Abraham LD: Gains in range of an- Vol. 3, The Back and Limbs. Harper & Row, New kle dorsiflexion using three popular stretching York, 1982 (pp. 775-778, Fig. 9-36). techniques. Am J Phys Med 6 5 : 1 8 9 - 1 9 6 , 1986. 6 5 . Ibid. (p. 783, Fig. 9 - 1 5 ) . 40. Evjenth O, Hamberg J: Muscle Stretching in Manual Therapy, A Clinical Manual, Vol. 1, The 66. Homans J: Thrombosis of the deep leg veins Extremities. Alfta Rehab Ferlag, Alfta, Sweden, due to prolonged sitting. N Engl J Med 2 5 0 : 1 4 8 - 1984 (p. 143). 149, 1954. 4 1 . Ibid. (pp. 1 4 4 - 1 4 5 ) . 67. Hufschmidt HJ, Sell G: Uber gekreuzte Reflexe 42. Fasel J, Dick W: Akzessorische Muskeln in der in Beinmotorik des Menschen. Z Orthop 116: Regio retromalleolaris medialis. Z Orthop 122: 60-65, 1978. 835-837, 1984. 68. Janda V: Muscle Function Testing. Butterworths, London, Boston, 1983 (pp. 189, 191-193, 198, 229).
458 Part 3 / Leg, Ankle, and Foot Pain 69. Jones DC, James SL: Overuse injuries of the cord injured patients. Arch Phys Med Rehabil lower extremity: shin splints, iliotibial band 69:661-664, 1988. friction syndrome, and exertional compart- 96. Michael RH, Holder LE: The soleus syndrome. ment syndromes. Clin Sports Med 6 : 2 7 3 - 2 9 0 , A cause of medial tibial stress (shin splints). 1987. Am J Sports Med 7 3 : 8 7 - 9 4 1985. 70. Joseph J, Nightingale A: Electromyography of 97. Milbradt H, Reimer P, Thermann H: [Ul- muscles of posture: leg and thigh muscles in trasonic morphology of the normal Achilles women, including the effects of high heels. J Physiol 7 3 2 : 4 6 5 - 4 6 8 , 1 9 5 6 . tendon and pattern of pathological changes.] 7 1 . Kendall FP, McCreary EK: Muscles, Testing and Radiologe 2 8 : 3 3 0 - 3 3 3 , 1 9 8 8 . Function, Ed. 3. Williams & Wilkins, Baltimore, 9 8 . Moller M, Ekstrand J, Oberg B, et al.: Duration 1983 (pp. 145-146). of stretching effect on range of motion in lower extremities. Arch Phys Med Rehabil 6 6 : 1 7 1 - 1 7 3 , 72. Kukulka CG, Russell AG, Moore MA: Electrical 1985. and mechanical changes in human soleus mus- 99. Moore MP: Shin splints: diagnosis, manage- cle during sustained maximum isometric con- ment, prevention. Postgrad Med 8 3 : 1 9 9 - 2 1 0 , tractions. Brain Res 3 6 2 : 4 7 - 5 4 , 1986. 73. Levine M, Lombardo J, McNeeley J, et al.: An 1988. 100. Nance EP Jr, Heller RM, Kirchner SG, et al.: Ad- analysis of individual stretching programs of intercollegiate athletes. Phys Sportsmed 15: vanced Exercises in Diagnostic Radiology. 17. 130-138, 1987. Emergency Radiology of the Pelvis and Lower 74. Lewis CE Jr, Mueller C, Edwards WS: Venous Extremity. W.B. Saunders Co., Philadelphia, stasis on the operating table. Am J Surg 124: 1983 (pp. 28-29). 780-784, 1972. 75. Lewit K: Manipulative Therapy in Rehabilitation of 101. Nardone A, Schieppati M: Shift of activity the Motor System. Butterworths, London, 1985 from slow to fast muscle during voluntary (pp. 151, 152, Figs. 4.40, 4.41). lengthening contractions of the triceps surae 76. Ibid. (pp. 2 8 2 - 2 8 3 , Fig. 6.104). muscles in humans. J Physiol 3 9 5 : 3 6 3 - 3 8 1 , 77. Lieberman CM, Hemingway DL: Scintigraphy 1988. of shin splints. Clin Nucl Med 5:31, 1 9 8 0 . 102. Nelimarkka O, Lehto M, Jarvinen M: Soleus 78. Lockhart RD: Living Anatomy, Ed. 7. Faber & muscle anomaly in a patient with exertion Faber, London, 1974 (Fig. 118). pain in the ankle. A case report. Arch Orthop 79. Lockhart RD, Hamilton GF, Fyfe F W : Anatomy Trauma Surg 7 0 7 : 1 2 0 - 1 2 1 , 1 9 8 8 . 103. Netter FH: The Ciba Collection of Medical Illustra- of the Human Body, Ed. 2. J.B. Lippincott Co., tions, Vol. 8, Musculoskeletal System. Part I: Philadelphia, 1969 (p. 650). Anatomy, Physiology and Metabolic Disorders. 80. Lorentzon R, Wirell S: Anatomic variations of Ciba-Geigy Corporation, Summit, 1987 (pp. 98, the accessory soleus muscle. Acta Radiol 28: 99). 627-629, 1987. 104. Ibid. (p. 101). 8 1 . Lozach P, Conard JP, Delarue P, et al.: [A case 1 0 5 . Ibid. (pp. 103, 105). 1 0 6 . Ibid. (p. 109). of an accessory soleus muscle.] Rev Chir Orthop 107. Nichols GW, Kalenak A: The accessory soleus 68:391-393, 1982. muscle. Clin Orthop 7 9 0 : 2 7 9 - 2 8 0 , 1 9 8 4 . 82. Ludbrook J: The musculovenous pumps of the 108. Nicolaides AN, Kakkar W, Field ES, et al.: Op- human lower limb. Am Heart J 7 7 : 6 3 5 - 6 4 1 , timal electrical stimulus for prevention of deep 1966. vein thrombosis. Br Med J 3 : 7 5 6 - 7 5 8 , 1972. 83. Markhede G, Nistor L: Strength of plantar flex- 109. Okada M: An electromyographic estimation of ion and function after resection of various the relative muscular load in different human parts of the triceps surae muscle. Acta Orthop postures. J Hum Ergol 7 : 7 5 - 9 3 , 1972. Scand 5 0 : 6 9 3 - 6 9 7 , 1 9 7 9 . 84. Mastaglia FL, Venerys J, Stokes BA, et al.: Com- 110. Okada M, Fujiwara K: Muscle activity around pression of the tibial nerve by the tendinous the ankle joint as correlated with the center of arch of origin of the soleus muscle. Clin Exp foot pressure in an upright stance. In Bio- Neurol 1 8 : 8 1 - 8 5 , 1 9 8 1 . mechanics VIIIA, edited by H. Matsui, K. 85. McLachlin J, McLachlin AD: The soleus pump Kobayashi. Human Kinetics Publ., Champaign, in the prevention of venous stasis during sur- IL, 1983 (pp. 209-216). gery. Arch Surg 7 7 : 5 6 8 - 5 7 5 , 1 9 5 8 . 8 6 . McMinn RMH, Hutchings RT: Color Atlas of 111. Ozburn MS, Nichols JW: Pubic ramus and ad- Human Anatomy. Year Book Medical Publishers, ductor insertion stress fractures in female basic Chicago, 1977 (p. 277B). trainees. Milit Med 7 4 6 : 3 3 2 - 3 3 3 , 1981. 87. Ibid. (pp. 2 8 1 , 282, 2 8 5 ) . 112. Pavlov H, Heneghan MA, Hersh A, et al: The 8 8 . Ibid. (p. 2 8 9 ) . 8 9 . Ibid. (p. 3 1 2 B ) . Haglund syndrome: initial and differential di- 9 0 . Ibid. (p. 315C, No. 11). agnosis. Radiology 7 4 4 : 8 3 - 8 8 , 1 9 8 2 . 9 1 . Ibid. (p. 3 1 6 ) . 9 2 . Ibid. (p. 3 1 7 ) . 113. Percy EC, Telep GN: Anomalous muscle in the 9 3 . Ibid. (p. 3 2 0 ) . leg: soleus accessorium. Am J Sports Med 12: 9 4 . Ibid. (p. 3 2 1 ) . 9 5 . Merli GJ, Herbison GJ, Ditunno JF, et al.: Deep 447-450, 1984. 114. Pernkopf E: Atlas of Topographical and Applied vein thrombosis: prophylaxis in acute spinal Human Anatomy, Vol.2. W.B. Saunders, Phila- delphia, 1964 (Figs. 347, 381). 1 1 5 . Ibid. (Fig. 356). 116. Ibid. (Fig. 3 5 7 ) . 117. Ibid. (Fig. 3 5 8 ) .
Chapter 22 / Soleus and Plantaris Muscles 459 118. Perry J: The mechanics of walking. Phys Ther 140. Sj0gaard G: Capillary supply and cross-sec- 47:778-801, 1967. tional area of slow and fast twitch muscle fib- res in man. Histochemistry 7 6 : 5 4 7 - 5 5 5 , 1 9 8 2 . 119. Perry J, Easterday CS, Antonelli DJ: Surface 141. Spalteholz W: Handatlas der Anatomie des Men- schen, Ed. 11, Vol.2. S. Hirzel, Leipzig, 1922 (p. versus intramuscular electrodes for electromy- ography of superficial and deep muscles. Phys 441). Ther 6 1 : 7 - 1 5 , 1 9 8 1 . 142. Ibid. (p. 4 4 2 ) . 143. Ibid. (p. 4 4 5 ) . 120. Pettersson H, Giovannetti M, Gillespy T III, et al.: Magnetic resonance imaging appearance of 144. Sutherland DH: An electromyographic study of supernumerary soleus muscle. Eur J Radiol 7: the plantar flexors of the ankle in normal walk- 149-150, 1987. ing on the level. J Bone Joint Surg [Am] 4 8 : 6 6 - 121. Prescott SM, Pearl JE, Tikoff G: \"Pseudo- 71, 1966. pseudothrombophlebitis\": ruptured popliteal 145. Sutherland DH, Cooper L, Daniel D: The role of cyst with deep venous thrombosis. N Engl J the ankle plantar flexors in normal walking. J Med 299:1193, 1978. Bone Joint Surg [Am] 6 2 : 3 5 4 - 3 6 3 , 1 9 8 0 . 122. Ramchandani P, Soulen RL, Fedullo LM, et al.: 146. Taunton JE, Maxwell TM: Intermittent claudi- Deep vein thrombosis: significant limitations of noninvasive tests. Radiology 156:47—49, cation in an athlete—popliteal artery entrap- ment: a case report. Can J Appl Sport Sci 7 : 1 6 1 - 1985. 123. Rasch PJ, Burke RK: Kinesiology and Applied 163, 1982. 147. Toldt C: An Atlas of Human Anatomy, translated Anatomy, Ed. 6. Lea & Febiger, Philadelphia, by M.E. Paul, Ed. 2, Vol. 1. Macmillan, New 1978 (pp. 318-319). York, 1919. 124. Ricci MA: Deep venous thrombosis in ortho- 148. Traccis S, Rosati G, Patraskakis S, et al.: Influ- paedic patients. Current techniques in precise ences of neck receptors on soleus motoneuron diagnosis. Orthop Rev 7 3 : 1 8 5 - 1 9 6 , 1984. excitability in man. Exp Neurol 9 5 : 7 6 - 8 4 , 1 9 8 7 . 125. Rohen JW, Yokochi C: Color Atlas of Anatomy, 149. Travell J: Symposium on mechanism and man- Ed. 2. Igaku-Shoin, New York, 1988 (p. 412). agement of pain syndromes. Proc Rudolf 126. Ibid. (pp. 4 2 1 , 4 4 6 ) . Virchow Med Soc 1 6 : 1 2 6 - 1 3 6 , 1957. 127. Ibid. (p. 4 2 2 ) . 128. Ibid. (p. 4 2 6 ) . 150. Travell J, Rinzler SH: The myofascial genesis of pain. Postgrad Med 1 1 : 4 2 5 - 4 3 4 , 1 9 5 2 . 129. Romano C, Schieppati M: Reflex excitability of 151. Travell JG, Simons DG: Myofascial Pain and Dys- human soleus motoneurones during voluntary function: The Trigger Point Manual. Williams & shortening or lengthening contractions. J Physiol 9 0 : 2 7 1 - 2 8 1 , 1987. Wilkins, Baltimore, 1983. 152. Ibid. (pp. 1 1 4 - 1 6 4 ) . 130. Romanus B, Lindahl S, Stener B: Accessory soleus muscle. 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Walz D, Craig BM, McGinnis KD: Bone imag- in humans. EurJAppI Physiol 51:395—408,1983. ing showing shin splints and stress fractures. 134. Shiavi R, Griffin P: Changes in electromy- Clin Nucl Med 72:822, 1987. ographic gait patterns of calf muscles with 157. Weber EF: Ueber die Langenverhaltnisse der walking speed. AIEEE Trans Biomed Eng 3 0 : 7 3 - Fleischfasern der Muskeln in Allgemeinen. 76, 1983. Berichte Ciber die Verhandlungen der Kdniglich Sachsischen Gesellschaft der Wissenschaften zu 135. Simons DG, Travell JG: Myofascial origins of Leipzig 3 : 6 3 - 8 6 , 1 8 5 1 . 158. Wiley JP, Clement DB, Doyle DL, et al.: A pri- low back pain. 3. Pelvic and lower extremity muscles. Postgrad Med 7 3 : 9 9 - 1 0 8 , 1 9 8 3 (see mary care perspective of chronic compartment syndrome of the leg. Phys Sportsmed 7 5 : 1 1 1 - pp. 104, 105). 120, 1987. 136. Simons DG, Travell JG: Myofascial pain syn- dromes, Chapter 25. In Textbook of Pain, edited 159. Winkel J, Bendix T: Muscular performance by P.D. Wall and R. Melzack, Ed 2. Churchill during seated work evaluated by two different EMG methods. Eur J Appl Physiol 5 5 : 1 6 7 - 1 7 3 , Livingstone, London, 1989 (pp. 368-385, see 1986. p. 378). 160. Wood J: On some varieties in human myology. 137. Simpson K: Shelter deaths from pulmonary Proc R Soc Lond 7 3 : 2 9 9 - 3 0 3 , 1 8 6 4 . embolism. Lancef 2:744, 1940. 161. Yang JF, Winter DA: Surface EMG profiles dur- 138. Singer A: Bed rest, deep-vein thrombosis, and ing different walking cadences in humans. pulmonary embolism. JAMA 250:3162, 1 9 8 3 . Electroencephalogr Clin Neurophysiol 6 0 : 4 8 5 - 139. Singer AE: Management of heel pain. JAMA 491, 1985. 239:1131-1132, 1978.
CHAPTER 23 Tibialis Posterior Muscle \"Runner's Nemesis\" HIGHLIGHTS: REFERRED PAIN from myofascial a deep posterior compartment syndrome, chronic trigger points (TrPs) in the tibialis posterior muscle tenosynovitis of the posterior tibial tendon, and concentrates proximally over the Achilles tendon tendon rupture. ACTIVATION of TrPs in the tibialis above the heel. A spillover pattern extends from posterior muscle results from chronic postural the TrP down over the calf, the entire heel, and overload (such as jogging on uneven surfaces) or the plantar surface of the foot and toes. ANA- as secondary TrPs to other muscles in its func- TOMICAL ATTACHMENTS of the tibialis poste- tional unit. PATIENT EXAMINATION includes test- rior are, proximally, chiefly to the interosseous ing this muscle for functional weakness, restricted membrane and fibula and also to the tibia and in- range of motion, and for aching pain in the muscle termuscular septa. Distally, the tendon passes be- when it is actively contracted in the fully shortened hind the medial malleolus and anchors to the na- position. It also includes examining the patient for vicular, the calcaneus, each cuneiform, the cu- the Morton foot structure and for other causes of a boid, and the second, third, and fourth hyperpronating foot. ASSOCIATED TRIGGER metatarsals. FUNCTION of the tibialis posterior POINTS of the tibialis posterior usually develop in muscle is to prevent excessive pronation of the the flexor digitorum longus, flexor hallucis longus, foot during midstance of the walking cycle, to pre- and peroneal muscles. INTERMITTENT COLD vent excessive weight bearing on the medial side WITH STRETCH of this muscle should incorpo- of the foot, and to distribute body weight among rate augmented postisometric relaxation to maxi- the heads of the metatarsals. It acts primarily as a mize effectiveness. The application of reciprocal supinator (invertor and adductor) of the foot and, inhibition also facilitates muscle lengthening. The to a lesser degree, as an assistant to plantar flex- procedure concludes with rewarming of the skin ion of the foot. Weakness or absence of the mus- and several cycles of active motion, moving the cle causes a pronated foot with severe flexible tibialis posterior through its fully shortened and its pes valgus deformity that must be corrected within fully lengthened range. INJECTION of TrPs in this months of the loss to avoid permanent damage to muscle is generally not recommended. CORREC- the foot structure. SYMPTOMS caused by active TIVE ACTIONS include running or jogging with TrPs in the tibialis posterior muscle include pain in full arch support only on a smooth flat surface, but the sole of the foot when running or walking, es- nor on the sides of a crowned road or similar pecially on an uneven surface. The pain is felt se- slanted surface. The shoe needs correction when verely in the arch of the foot, Achilles tendon, and, the patient has the Morton foot structure or has a to a lesser degree, in the heel, toes, and calf. hypermobile midfoot. Augmented postisometric Other conditions that need to be considered in re- relaxation in a home program maintains full range lation to tibialis posterior TrPs include shin splints, of motion of the tibialis posterior muscle. 1. REFERRED PAIN gle-muscle syndrome. The pain concen- (Fig. 23.1) trates primarily over the Achilles tendon above the heel and has a spillover pattern Pain due to myofascial trigger points that spreads from the TrP distally through (TrPs) in the tibialis posterior muscle the midcalf down to the heel and over the (Fig. 23.1) is not likely to present as a sin- entire plantar surface of the foot and toes. 460
Chapter 23 / Tibialis Posterior Muscle 461 with that of the flexor digitorum longus.65 The attachment to the fibula usually in- cludes an intramuscular septum, in which case the muscle is multipennate.52 In the lower fourth of the leg, its tendon passes deep (anterior) to that of the flexor digitorum longus.18,61 The two tendons pass behind the medial malleolus to- gether but in separate sheaths. The tibi- alis posterior tendon then passes deep to the flexor retinaculum and superficial to the deltoid ligament. The tendon usually contains a sesamoid fibrocartilage near where it passes superficial to the plantar calcaneonavicular ligament.10,19 Distally it a n c h o r s to t h e p l a n t a r sur- face of most of the bones that form the arch of the foot (Fig. 23.2), primarily to the navicular, but also to the calcaneus, each cuneiform, the cuboid, and the base of the second, third, and fourth metatar- sals.19 The fibular portion of the muscle is more extensive than the tibial portion.10,52 Figure 23.1. Composite pain pattern (bright red) re- Occasionally, the tibialis posterior muscle may ferred from trigger points (Xs) at their common location be doubled,10 or it may have an anomalous inser- in the right tibialis posterior muscle (darker red). The tion of its tendon to an enlarged navicular tuber- essential pain pattern (solid dark red) denotes where osity.66 pain is usually experienced when these trigger points are active. Red stippling indicates the occasional ex- Supplemental References tension of the essential pain pattern. Netter15 drew the tibialis posterior, including all 2. ANATOMICAL ATTACHMENTS AND attachments in phantom, from the front view. CONSIDERATIONS (Fig. 23.2) The view from behind without blood vessels shows the arrangement of the tendons at the an- The tibialis posterior is the most deeply kle,5 the attachments of the tibialis posterior ten- located muscle in the calf. It lies between don to bones in the foot,5815 the relation of the the interosseus membrane anteriorly and tibialis posterior muscle to the, adjacent flexor dig- the soleus muscle posteriorly (see Fig. itorum longus and flexor hallucis longus deep to 2 3 . 5 ) . Proximally it a t t a c h e s p r i m a r i l y to the soleus muscle,27, 45 and the crossing of the ten- the interosseous membrane and to the don of the tibialis posterior deep to that of the medial surface of the fibula (Fig. 23.2); it flexor digitorum longus.61 The posterior view por- also attaches to the lateral portion of the trays the relation of the tibialis posterior muscle to posterior surface of the body of the tibia, the tibial and peroneal arteries and the tibial the deep transverse fascia, and to in- nerve,4,55 and to only the tibial nerve.56 termuscular septa of adjacent muscles.15,19 The tibial attachment of the muscle com- Views from the medial side of the ankle region monly continues into the distal third of also show the relation of the tendon to other ten- the leg as far as, or more distal than, the dons and to the ligaments and bones.6,24,47 crossing of the tibialis posterior tendon An uninterrupted series of 12 cross sections17 clarifies this muscle's relation to other muscles and to neurovascular structures throughout its length. A series of four cross sections provides this information for the fleshy part of the muscle (see Fig. 23.5). Other authors present a cross sec- tion through the middle third of the leg.3,26
462 Part 3 / Leg, Ankle, and Foot Pain Foramen for vessels Figure 23.2. Attachments of the right tibialis posterior muscle (red). The bones Tibialis to which this muscle attaches are dark- posterior ened. Note the Morton foot (short first, long second metatarsal) structure. Fibula Interosseous membrane Tibia Tibialis posterior Calcaneus tendon Cuboid bone Navicular 2nd, 3rd, and 4th bone metatarsal bones Cuneiform bone A posterior view2,25 and a posterolateral view43 weight among the heads of the metatar- locate where the posterior tibial muscle attaches sals, helping shift weight toward the lat- to the bones of the leg. A plantar view shows eral side of the foot. This muscle appears where its tendon attaches to the bones of the to restrain the valgus thrust on the ankle f o o t . '7 , 1 5 , 2 8 , 4 4 One figure shows all bony attach- that occurs during the early stance phase ments.57 of walking. During midstance, it prevents excessive lateral inclination of the leg and Photographs depict the surface contours pro- provides transverse plane balance. It pre- duced by the tibialis posterior tendon at the an- vents excessive pronation of the foot, kle.37,40,46 thereby preventing excessive medial rota- tion (spiraling) of the leg. It has been 3. INNERVATION suggested that during stance, the tibialis posterior assists other plantar flexors in The tibial nerve supplies the tibialis pos- controlling (decelerating) the forward terior muscle with fibers from the fifth movement of the tibia over the fixed foot. lumbar and first sacral spinal nerves.19 When the foot is free (not weight bearing), the tibialis posterior acts to invert and ad- 4. FUNCTION duct the foot and to assist in plantar flex- ion. For weight bearing, the tibialis posterior muscle functions to distribute body
Chapter 23 / Tibialis Posterior Muscle 463 Actions cessive lateral inclination of the leg over the fixed foot.41 The tibialis posterior muscle supinates (inverts and adducts) the f o o t . '1 0 , 1 9 , 3 , 6 0 Some authors con- Perry and coauthors59 compared the myoelectric sider it a major plantar flexor also,10,3,'80 but others activity of the tibialis posterior muscle during do not consider plantar flexion one of its primary slow, free, and fast gait with the amount of activ- actions.19,21 ity generated by various degrees of voluntary ef- fort graded according to muscle testing criteria. In electrical stimulation studies of the muscle, Results showed that EMG activity increased di- Duchenne21 found that the foot adducted with rectly as more muscular force was required during great force, but, when plantar flexed or dor- the different manual muscle test levels and with siflexed, returned weakly to neutral. Sutherland68 increased walking speeds. calculated that the tibialis posterior potentially is the third most powerful plantar flexor; however, it Based on its myoelectric activity, the tibialis could exert only 6% of the moment of force con- posterior does not contribute significantly to arch tributed by the gastrocnemius and soleus muscles support under static load conditions.11,13 How- combined. ever, the changes in the foot that occur in the ab- sence of the force exerted by this muscle show Functions that it is essential for maintenance of normal foot configuration and posture. Co-contractions of the Walking tibialis posterior with the peroneus longus may help support the medial arch and prevent hyper- The tibialis posterior muscle prevents eversion of pronation of the foot, especially in runners.1 the foot beyond the neutral position during mid- stance of the walking cycle.29 It distributes body Weakness or Absence weight on the heads of the metatarsals, helping shift weight toward the lateral side of the foot Duchenne noted that, in patients with tibialis pos- which has the strong plantar ligaments that equip terior deficit, the foot turned outward when they it well to bear body weight.12,54 Perry58 suggested were walking or standing.22 Weakness of this mus- that the tibialis posterior appears to restrain the cle can lead to an excessively pronated foot, un- valgus thrust on the ankle that occurs during the locking of the midtarsal joint that allows plantar early stance phase of walking. Sutherland68 con- subluxation of the hindfoot on the forefoot, and cluded that the plantar flexors, including the tibi- development of a severe pes valgus deformity.30 alis posterior, control (decelerate) the forward Tendon rupture or weakness of the tibialis poste- movement of the tibia over the fixed foot during rior caused by slippage of the tendon around the stance, indirectly providing knee stabilization. medial malleolus will quickly cause a flexible pes During level walking in normal subjects, it is not valgus deformity.42 Loss of tibialis posterior func- active at heel-off (or shortly after) when this tion may result in progressive and dramatic col- would be required if it were functioning as a plan- lapsing pes valgo planus deformity with a marked tar flexor.12 In flat-footed subjects, this muscle is abduction component. If uncorrected within active throughout stance phase and maintains in- months of loss, tendon transfer alone will no version of the foot, which keeps the body weight longer suffice and arthrodesis will be required.50 on the lateral border of the sole.29 Rupture of the tibialis posterior tendon due to In a study of 11 normal adults, Matsusaka41 rheumatoid arthritis caused a sag in the medial tested gait by measuring ground reaction forces, longitudinal arch on weight bearing within 10 myoelectric activity, and the degree of pronation- days. In another patient, examination 2'/2 years af- supination of the foot. He found that when the lat- ter rupture revealed a collapsed, but mobile, lon- eral component of ground reaction force was gitudinal arch. Radiographs of the foot showed large, the degree of pronation of the foot was marked osteopenia, a valgus heel calcaneal angle, small, and activity in the tibialis posterior disap- and anterior and inferior displacement of the talar peared early. Conversely, when the lateral compo- head.20 nent of force was small, the degree of pronation was larger and the tibialis posterior (also flexor 5. FUNCTIONAL (MYOTATIC) UNIT digitorum longus and extensor hallucis longus) showed extended myoelectric activity.41 This sug- The flexor digitorum longus and flexor gests that the force necessary to throw the weight hallucis longus muscles are agonists for onto the lateral sole can be supplied largely by the the primary non-weight-bearing action of motion of the body or by the tibialis posterior and the tibialis posterior, inversion of the other invertor muscles. Matsusaka suggested that foot, and also for the weaker action of the tibialis posterior functions by preventing ex- plantar flexion. These toe flexors are ago-
464 Part 3 / Leg, Ankle, and Foot Pain nists also for the weight-bearing function during exercise in poorly conditioned of assisting transverse plane balance. athletes or novice runners, and it is spe- Other muscles that also assist inversion cifically attributed to the posterior tibial are the tibialis anterior and extensor hal- muscle by these authors. In those individ- lucis longus. Other agonists for plantar uals whose tibialis posterior attachment flexion include the gastrocnemius, so- to the tibia extends well into the lower leus, plantaris, and the peroneus longus third of the leg, as far as or distal to the and brevis muscles. crossing of its tendon with that of the flexor digitorum longus, excessive prona- The chief muscular antagonists to the tion would severely strain this region of tibialis posterior's strong inversion action distal attachment.65 This condition re- are the peroneal muscles; gravity is the quires only conservative treatment, not primary antagonist when the individual surgery.15 On the other hand, a deep pos- is weight bearing. terior compartment syndrome can require surgery. 6. SYMPTOMS A female aerobic dancer abruptly developed An individual with active TrPs in the pain bilaterally in the mid-distal tibias, postero- tibialis posterior muscle is likely to medially (shin splints). Radionuclide bone scan complain of pain in the foot when run- revealed hyperconcentration of activity in the ar- ning or walking. The pain is felt se- eas of pain, which corresponded to the attach- verely in the sole of the foot and Achil- ments of the tibialis posterior muscles. The pa- les tendon, and also to a lesser degree tient recovered within a few days with rest.14 She in the midcalf and heel. It is especially apparently had suffered overload stress along the bothersome during walking or running tibial attachment of this muscle. on uneven surfaces, e.g., on gravel or over old bricks or cobblestones that are How to tell whether these symptoms are caused sufficiently irregular to require addi- by a chronic compartment syndrome requiring tional stabilization of the foot. surgery is controversial. One group of surgeons re- ported an 88% success rate on 26 leg compartment Differential Diagnosis syndromes, performing the operation only after conservative measures failed, but without measur- Serious dysfunction of the tibialis poste- ing intramuscular pressures.70 Other surgeons rior muscle/tendon complex is not unu- who performed fasciotomy of the deep posterior sual and deserves careful consideration in compartment based on intramuscular pressure the differential diagnosis of ankle and criteria did not achieve results that were as good foot pain. as those obtained when treating the anterior com- partment syndrome surgically.63 In this series of Shin Splints and Deep Posterior eight patients, a deep posterior compartment syn- Compartment Syndrome drome was diagnosed if intramuscular pressure was more than 15 mm Hg at rest, if it increased Chapters 19, 20, and 22 of this volume during exercise, and if it showed a delayed return make note of relevant compartment syn- to the pre-exercise level.63 dromes and shin splints. Most authors identify four muscular compartments in However, using stringent intramuscular pres- the leg: the anterior, lateral, superficial sure criteria, Melberg and Styf48 were unable to posterior, and deep posterior compart- find anyone among 25 patients with exercise-in- ments.51,53 The deep posterior compart- duced posteromedial pain in the lower leg who ment contains the tibialis posterior mus- qualified for the diagnosis of deep posterior com- cle, the flexor digitorum longus, and the partment syndrome. The authors made no sugges- flexor hallucis longus. Surgically, the tibi- tion as to what was causing the patients' pain. Ap- alis posterior behaves as if it has an addi- parently, they did not consider the possibility of tional compartment of its own.62,63 myofascial TrPs in the deep posterior compart- ment musculature. Myofascial TrPs could cause Some authors consider the term \"shin pain on exertion without producing a true com- splints\" to apply only to pain along the partment syndrome. inner (medial) distal two-thirds of the tib- ial shaft.15,16,70 It is considered to be an overuse syndrome that usually develops
Chapter 23 / Tibialis Posterior Muscle 465 Tibialis Posterior Tendon Dysfunction tendon is valuable. This stage requires surgical re- Johnson and Strom36 clearly explain and pair of the tendon.36 diagram three successive stages of tibialis posterior tendon dysfunction: (a) tendon In stage 3, damage to the static supports of the length normal with minimal pain and dys- function; (b) tendon elongated, hindfoot mo- foot have resulted in fixed flatfoot and requires re- bile with medial foot pain during and af- ter weight bearing, serious dysfunction, alignment of the foot structures and arthrodesis. and displacement of bones of the foot; and (c) tendon elongated, hindfoot deformed An isolated subtalar arthrodesis suffices in most and stiff with lateral foot pain and marked eversion of the foot when bearing weight. cases.36 Stage 1 shows weakness of tibialis posterior As noted repeatedly in both this volume and in function when the patient tries to perform the sin- gle-heel-rise test while standing on one foot. Nor- Volume l,69 muscles with myofascial TrPs are mally, the tibialis posterior muscle first inverts and locks the hindfoot to provide a rigid structure weakened without atrophy. They also are under that permits transfer of weight to the forefoot. In stage 1, initial heel inversion is weak and the pa- continuous increased tension because of taut tient either raises the heel incompletely without locking the hindfoot, or fails to rise onto the ball bands. Thus, myofascial dysfunction in the tibi- of the foot. Pain and tenderness are found along the path of the tendon, chiefly just before it passes alis posterior muscle is one condition that could behind the medial malleolus and medial to its pri- mary navicular insertion. Unfortunately, patients possibly account for Johnson and Strom's stage 1 do not usually present with this dysfunction as a chief complaint, but it is at this early stage that the findings: a detectable muscle weakness under condition should be fully correctable, often with conservative measures. The examiner must look high-load conditions, and degenerative changes of for this condition.36 The authors offered no sug- gestions as to why patients develop this condition the tendon exposed to abnormal sustained tension and gave no indication that the patients were ex- amined for myofascial TrPs that could make a sig- caused by taut bands. Subsequent stages could nificant contribution to their dysfunction. follow failure to correct the condition in its initial Hirsh and coauthors33 divide chronic tenosyno- vitis of the tibialis posterior into three descriptive stage. categories: peritendinitis crepitans, stenosing te- nosynovitis, and chronic tenosynovitis with effu- A number of authors discuss rupture of the tibi- sion. Apparently all of these would fall within stage 1 as described by Johnson and Strom.36 alis posterior tendon as a separate entity (stages 2 With progression to stage 2, pain increases in and 3 of Johnson and Strom),9,20,32,39,49,64,66,67 in- severity and distribution and the patient has seri- ous difficulty in walking. The single-heel-rise test cluding a comprehensive review.34 The patient is more abnormal and the patient stands with the foot everted and abducted sufficiently to display presents with a complaint that \"my foot is becom- \"too many toes\" when viewed from behind. This is a simple, reproducible, and recordable measure ing flat,\" \"my shoe is running over,\" \"I can't walk of posture. Routine radiographs from the antero- posterior view show the forefoot abducted in rela- like I used to,\" or \"I have trouble going up and tion to the hindfoot because the calcaneus and na- vicular are subluxed laterally off the head of the down stairs.\" Frequently, the absence of the dis- talus. In lateral view, the talus is tipped forward in relation to the calcaneus. A tomogram is rarely placed tendon is noted on palpation when com- helpful but magnetic resonance imaging of the pared with the normal side. The discontinuity of the tendon has been imaged by ultrasound and by magnetic resonance imaging.20 7. ACTIVATION AND PERPETUATION OF TRIGGER POINTS Running and jogging, especially on un- even ground or on laterally slanted sur- faces, may activate and will perpetuate TrPs in this muscle. Interestingly, tibialis posterior TrPs are not commonly ob- served in tennis players who characteris- tically work out on smooth level surfaces and wear shoes that provide ample foot support. Conversely, footwear that is badly worn and that encourages eversion and rocking of the foot promotes TrPs in this muscle. Although some pronation in early stance is normal, hyperpronation can overload the tibialis posterior muscle and may contribute to the activation, and cer- tainly to the perpetuation, of TrPs in it. The foot may excessively pronate due to a hypermobile midfoot, ankle equinus, muscular imbalance, a Morton foot struc-
466 Part 3 / Leg, Ankle, and Foot Pain ture, or some other cause. Chapter 20 of Muscles with active TrPs are likely to this volume reviews imbalance due to the develop cramplike pain when contracted Morton foot structure in detail. in the shortened position. If the tibialis posterior is involved and the patient tries A systemic perpetuating factor is to invert, adduct, and plantar flex the foot hyperuricemia with or without signs and fully, pain is likely to occur deep in the symptoms of gout in the big toe. Polymy- calf, where the muscle is located. algia rheumatica, like hyperuricemia, markedly increases the irritability and The ankle and foot should be examined susceptibility of the muscles to the devel- for joint hypermobility or hypomobility. opment and perpetuation of myofascial TrPs. Chapter 4 of Volume l 6 9 reviews The clinician identifies a Morton foot these and other perpetuating factors. structure by examining the patient's feet and shoes (see Section 8 in Chapter 20 of 8. PATIENT EXAMINATION this volume). By the time patients with tibialis posterior TrPs and this foot struc- If the tibialis posterior TrPs are active and ture are seen for their persistent foot pain, have been present for some time, the pa- they usually have tried one or more cor- tient walks with the foot partly everted rective devices. The device frequently and abducted, in a flatfooted gait. The pa- used is an insert that adds support to the tient should be observed walking bare- foot but often ends short of the head of foot, with the clinician looking particu- the first metatarsal, and needs only to be larly for a hyperpronating foot. extended with an adhesive felt pad to provide adequate support under the great The usual method of manually testing toe's metatarsal head. However, people the tibialis posterior muscle for strength37 with tibialis posterior TrPs frequently is unsatisfactory to identify relatively find that wearing a corrective orthotic de- slight weakness. Manual testing of this vice is painful because it presses on the muscle poorly discriminates its function region of tenderness referred from the from force substituted by agonist mus- TrPs to the sole of the foot. This referred cles.36,59 If manual testing is used, the ex- tenderness disappears promptly with in- aminer should watch for curling of any activation of the responsible TrPs. toes, indicating an effort to substitute the long flexors of the toes for the weak tibi- If hyperuricemia is suspected, the clini- alis posterior. Instead, the authors recom- cian should check for tophi in the upper mend the single-heel-rise test,36 described rim of the patient's ears. If a systemic con- previously on page 465; it specifically de- dition is suspected of perpetuating these tects the instability associated with weak- TrPs, the clinician should obtain an ness of the tibialis posterior. Active TrPs erythrocyte sedimentation rate to rule out in this muscle cause a perceptible degree many possibilities, including polymy- of functional weakness. algia rheumatica or other collagen dis- ease. To test this muscle for restricted range of motion, the patient may be supine or 9. TRIGGER POINT EXAMINATION seated. The clinician first fully everts and abducts the foot and then attempts to (Fig. 23.3) place it in dorsiflexion. Tibialis posterior TrPs painfully restrict this movement. Re- The TrPs in the tibialis posterior muscle striction of this movement can also be lie deep in the leg and are accessible to caused by tightness of the flexor dig- examination by palpation only indirectly itorum longus and flexor hallucis longus, through other muscles. At most, one can but not by the other major invertor, the only determine a direction of deep ten- tibialis anterior, because it is a dor- derness. Interpreting this tenderness as siflexor. If, at the limit of the restricted due to tibialis posterior TrPs depends on range of motion, the clinician can extend the preceding examination having estab- all five toes without pain, the restriction lished evidence of this muscle's involve- is caused by the tibialis posterior and not ment and on having reason to believe that by either of the long toe flexors. the intervening muscles are free of TrPs. As shown in Figures 19.3 and 23.5, the tibialis posterior is inaccessible to digital
Chapter 23 / Tibialis Posterior Muscle 467 Figure 23.3. Application of strong pressure beside tachment of this muscle is palpable in the middle third the gastrocnemius and through the soleus muscle to of the leg, also deep along the posterior border of the detect deep trigger-point tenderness in the right tibialis tibia. B, examination using the lateral approach, press- posterior muscle. The X marks the usual medial loca- ing medially. The solid circle (partial view) marks the tion for palpating this tenderness. A, examination us- head of the fibula. ing the medial approach. Tenderness of the tibial at- examination from in front because of the found myalgic spots [probably TrPs] that intervening interosseous membrane. referred pain and responded to conserva- tive therapy. From behind, one can usually elicit tenderness of tibialis posterior TrPs and 10. ENTRAPMENTS tenderness of that muscle's tibial attach- ment by pressing deeply between the pos- No neural or vascular entrapments by this terior border of the tibia and the soleus muscle have been observed, nor are any muscle, which can be partially displaced expected since it lies deep to the vessels posteriorly (Fig. 23.5). The muscle should and nerves. be examined for tenderness as illustrated in Figure 23.3A proximal to the midleg. 11. ASSOCIATED TRIGGER POINTS As one palpates distalward from the loca- tion illustrated, the flexor digitorum The two toe muscles that also invert and longus will also be encountered behind plantar flex the foot, the flexor digitorum the tibia. This more distal location on the longus and flexor hallucis longus, are medial border of the tibia is the same as commonly involved with the tibialis pos- that of \"shin-splint\" tenderness attrib- terior muscle. However, the primary foot uted to overstress of the tibialis posterior plantar flexors, the gastrocnemius and as noted in Section 6, Differential Diagno- soleus muscles, are not prone to develop sis. TrPs in association with the tibialis poste- rior. Occasionally, on the lateral side (Fig. 23.3B), one can elicit tenderness of the Active TrPs in the peroneal muscles, tibialis posterior muscle through the especially in patients with the Morton soleus and the flexor hallucis longus foot structure, are also commonly associ- muscles (see Fig. 19.3).53 ated with TrPs in the tibialis posterior muscle. The peroneus longus and per- Gutstein31 included the tibialis poste- oneus brevis muscles are prime antago- rior among those muscles in which he
468 Part 3 / Leg, Ankle, and Foot Pain Figure 23.4. Stretch position and vapocoolant spray the other hand, if the joints of the foot are pattern (thin arrows) for the right tibialis posterior mus- hypomobile, they should be mobilized. cle. The Xs mark locations that are usually most effec- tive for palpation using a medial or lateral approach. For intermittent cold with stretch, the Trigger points actually lie centrally between the two patient lies prone and relaxed in a com- sets of Xs. The foot should be moved into dorsiflexion fortable position on the examining table and then eversion (thick arrow) to stretch this muscle with the feet extending beyond the end passively. (Fig. 23.4). Pillows support the patient as necessary for comfort, and a blanket cov- nists to the inversion action of the tibialis ers the patient for warmth, if needed. The posterior, but are agonists to its plantar clinician demonstrates use of ice or suit- flexion and stabilization of the foot. able vapocoolant, and warns that it may feel startlingly cold. Then downward par- 12. INTERMITTENT COLD WITH allel sweeps of intermittent cold cover the STRETCH back of the leg, the heel, and the plantar (Fig. 23.4) surface of the foot (Fig. 23.4), while the clinician simultaneously grasps the ball Since injection of TrPs in the tibialis pos- of the foot and gently but firmly everts terior muscle is difficult and not recom- and dorsiflexes the foot to take up any mended, it is especially important to util- slack in the tibialis posterior muscle. Any ize effective noninvasive techniques for tension in the flexor digitorum longus releasing this muscle's tightness. and flexor hallucis longus can be released by simultaneously passively extending all The use of ice for applying intermittent five toes. cold with stretch is explained on page 9 of this volume and the use of vapocoolant The patient then initiates an augmented spray with stretch is detailed on pages postisometric relaxation procedure by 67-74 of Volume l . 6 9 Techniques that slowly taking in a full breath and, at the augment relaxation and stretch are re- same time, gently contracting the tibialis viewed on pages 10-11 of this volume. posterior muscle isometrically against re- sistance supplied by the clinician. At the Stretching through full range should beginning of a slow exhalation, the patient not be performed if either the hindfoot or concentrates on relaxing the whole body, the midfoot is hypermobile. In this case, particularly the limb under treatment. alternative treatment methods should be The clinician applies parallel sweeps of used (see pages 9-10 of this volume). On the stream of vapocoolant or applies par- allel strokes with ice in the pattern shown in Figure 23.4, while maintaining gentle but firm pressure into eversion and dor- siflexion to take up any slack that devel- ops in the tibialis posterior and associ- ated muscles. The first cycle concludes when the patient completes the total exha- lation and must take another breath. The treatment cycle is repeated in rhythm to the patient's slow, full respiratory cycle with careful attention to synchronization between the patient and the clinician. When no further gain in range of mo- tion occurs, the patient can then substi- tute relaxation during the exhalation phase with a voluntary effort to assist the clinician in placing the foot in eversion and dorsiflexion. This activation of antag- onists to the tibialis posterior weakens its stretch reflexes by reciprocal inhibition, thus increasing the effectiveness of inter- mittent cold with stretch.
Chapter 23 / Tibialis Posterior Muscle 469 Peroneal artery Gastrocnemius, Posterior and vein- lateral head side Fibula Gastrocnemius, medial head Soleus Posterior tibial artery and vein, and tibial nerve Anterior tibial artery Popliteus and vein, and Tibialis posterior leep peroneal nerve Peroneus longus Tibia terosseous membrane Gastrocnemius, lateral head Extensor digitorum Soleus longus Gastrocnemius, medial head Tibialis anterior Peroneal artery and vein Fibula Posterior tibial artery and vein Peroneus longus and brevis and tibial nerve Anterior tibial artery and vein, Popliteus and deep peroneal nerve Tibia Interosseous membrane Extensor digitorum longus Gastrocnemius and extensor hallucis longus Soleus Tibialis posterior Peroneal artery and vein Posterior tibial artery and Tibialis anterior Fibula vein, and tibial nerve Peroneus longus and brevis Flexor digitorum longus Anterior tibial artery and vein Interosseous membrane and deep peroneal nerve- Gastrocnemius Extensor digitorum longus Posterior tibial artery and vein, and tibial nerve and extensor hallucis longus' Tibialis posterior' Tibia Tibialis anterior Flexor digitorum Soleus' longus Peroneus longus and brevis' Tibia Tibialis posterior Fibula' Tibialis anterior Anterior Peroneal artery and vein' Anterior tibial artery and vein, side Extensor digitorum longus and extensor hallucis longus and deep peroneal nerve Interosseous membrane Figure 23.5. Four serial cross sections of the right calf of the prone patient. The levels of the cross sec- tibialis posterior muscle (medium red), in relation to tion are identified in the lower left corner. The flexor other muscles of the leg (light red), viewed from hallucis longus is not distinguished from the soleus above. Arteries are bright red, veins are black sur- muscle in the distal section. Adapted from A Cross- rounded by uncolored walls, and nerves are uncol- Section Anatomy, by Eycleshymer and Schoemaker, ored. These sections are oriented as one palpates the published by D. Appleton Company, 1911. Following use of the stretch procedures equalized. This helps prevent or inacti- described previously, the clinician ap- vate a recurrence of TrPs in this muscle. plies a moist heating pad to the skin over the treated muscle to rewarm the skin and The tibialis posterior lies under too to further release muscle tension as the many layers of other muscles to be readily patient relaxes in comfort. The patient accessible to massage therapy. Ultra- sound does reach it and can be used in t h e n p e r f o r m s s e v e r a l slowly a n d smoothly conjunction with stretch. e x e c u t e d c y c l e s of full a c t i v e r a n g e of m o - Evjenth and Hamberg23 describe and il- tion, placing the tibialis posterior succes- lustrate a bimanual method of stretching sively in the fully lengthened and fully the tibialis posterior muscle. shortened positions. 13. INJECTION AND STRETCH Finally, the patient learns how to per- (Fig. 23.5) form the postisometric relaxation tech- nique at home on a daily basis to main- The authors do not recommend injection tain the muscle's full stretch range of mo- of the tibialis posterior muscle, especially tion and to keep its sarcomere lengths from behind. Examination of Figure 23.5
470 Part 3 / Leg, Ankle, and Foot Pain shows that there is no access to the mus- If the TrP activity responds poorly to cle without passing close to nerves, arter- treatment, jogging or running as a form of ies, and veins. Since the muscle lies so exercise should be replaced by swimming deep, localization of the TrPs will be im- or bicycling. Initially, corrections made to precise. Figure 19.3 shows more clearly the insert of the shoe may be uncomforta- the details of this problem. The poor lo- ble due to referred tenderness from the calization of the TrPs in this muscle TrPs, but with resolution of the tibialis would require considerable probing for posterior TrPs, this related tenderness of the TrPs with the needle, which would the sole of the foot disappears. increase the danger of its encountering a nerve or an artery. If arterial bleeding re- Whether or not the individual runs or sulted, it might be difficult to know jogs, he or she should always wear a well- promptly that it was occurring, and even fitted shoe that is high enough to enhance more difficult to apply counter pressure lateral stability of the foot. If the heel effectively to stop the bleeding. counter of the shoe is too wide and loose (when a finger will slide in between the An injection approach to this muscle patient's heel and the shoe), the heel of was described and illustrated in detail by the shoe should be made snug by adding Rorabeck.62 He used an anterior approach pads inside the shoe beside the person's through the interosseous membrane to in- heel. sert a wick catheter into the tibialis poste- rior muscle. This procedure provided a High heels and spike heels must be measure of the muscle's intramuscular avoided. High top shoes may be necessary pressure in order to diagnose a suspected if other measures do not suffice. posterior compartment syndrome that would require surgical intervention. Lee Home Therapeutic Program et al.38 also described an anterior ap- proach for performing needle electromy- The patient needs to perform an aug- ography on this muscle. mented postisometric relaxation exercise daily, as described previously in Section 14. CORRECTIVE ACTIONS 12. Properly performed, this should keep the muscle free of recurrent TrPs unless Corrective Body Mechanics the patient has significant unresolved perpetuating factors, which may be not A patient with active tibialis posterior only mechanical, but systemic, as dis- TrPs who is a runner or jogger should ex- cussed on pages 114-155 in Volume l . 6 9 ercise on a smooth surface and wear shoes with adequate arch support. Pads References should be added to the shoe beneath the head of the first metatarsal to correct for a 1. Anderson A: Personal communication, 1991. Morton foot structure, if present (see 2. Anderson JE: Grant's Atlas of Anatomy, Ed. 8. Wil- Chapter 20, Figs. 20.4-20.7 and 20.12- 20.14). If there is hyperpronation due to a liams & Wilkins, Baltimore, 1983 (Figs. 4-70, 4- hypermobile midfoot, a good arch sup- 81). port should be used. If muscle imbalances 3. Ibid. (Fig. 4 - 7 2 ) . are present, they should be corrected. 4. Ibid. (Fig. 4 - 8 6 ) . 5. Ibid. (Fig. 4 - 9 5 ) . Corrective Posture and Activities 6. Ibid. (Fig. 4 - 9 8 ) . 7. Ibid. (Fig. 4 - 1 0 7 ) . In patients with painful hyperpronating 8. Ibid. (Fig. 4 - 1 1 7 ) . \"runners' feet,\" the problem may be cor- 9. Banks AS, McGlamry ED: Tibialis posterior ten- rected by exercises to increase the endur- don rupture. J Am Podiatr Med Assoc 7 7 : 1 7 0 - 1 7 6 , ance and aerobic capacity of both the tibi- 1987. alis posterior and peroneus longus mus- 10. Bardeen CR: The musculature, Sect. 5. In Mor- cles.1 ris's Human Anatomy, edited by C M . Jackson, Ed. 6. Blakiston's Son & Co., Philadelphia, 1921 (pp. Walking and running should be con- 522, 523). fined to smooth, level surfaces. 11. Basmajian JV, Deluca CJ: Muscles Alive, Ed. 5. Williams & Wilkins, Baltimore, 1985 (pp. 3 4 2 - 345). 12. Ibid. (pp. 3 7 7 - 3 7 8 ) . 13. Basmajian JV, Stecko G: The role of muscles in arch support of the foot. An electromyographic
Chapter 23 / Tibialis Posterior Muscle 471 study. J Bone Joint Surg [Am] 4 5 : 1 1 8 4 - 1 1 9 0 , 41. Matsusaka N: Control of the medial-lateral bal- ance in walking. Acta Orthop Scand 5 7 : 5 5 5 - 5 5 9 , 1963. 1986. 14. Brill DR: Sports nuclear medicine bone imaging for lower extremity pain in athletes. Clin Nucl 42. McGlamry ED, Mahan KT, Green DR: Pes valgo Med 8 : 1 0 1 - 1 0 6 , 1 9 8 3 . planus deformity, Chapter 12. In Comprehensive Textbook of Foot Surgery, edited by E.D. Mc- 15. Brody DM: Running injuries. Clin Symp 3 2 : 1 - 3 6 , Glamry, Vol. 1. Williams & Wilkins, Baltimore, 1980 (pp. 15, 18-19). 1987 (pp. 4 0 3 - 4 6 5 , see p. 411). 16. Bryk E, Grantham SA: Shin splints. Orthop Rev 4 3 . McMinn RMH, Hutchings RT: Color Atlas of 12:29-40, 1983. Human Anatomy. Year Book Medical Publishers, 17. Carter BL, Morehead J, Wolpert SM, et al.: Cross- Chicago, 1977 (pp. 282, 285). Sectional Anatomy. Appleton-Century-Crofts, 44. Ibid. (p. 289). 4 5 . Ibid. (p. 315). New York, 1977 (sects. 72-83). 46. Ibid. (p. 318). 18. Clemente CD: Gray's Anatomy of the Human Body, 47. Ibid. (p. 320). American Ed. 30. Lea & Febiger, Philadelphia, 48. Melberg P-E, Styf J: Posteromedial pain in the lower leg. Am J Sports Med 7 7 : 7 4 7 - 7 5 0 , 1 9 8 9 . 1985 (p. 578, Fig. 6-78). 19. Ibid. (p. 579). 49. Mendicino SS, Quinn M: Tibialis posterior dys- 20. Downey DJ, Simkin PA, Mack LA, et al.: Tibialis function: an overview with a surgical case re- posterior tendon rupture: a cause of rheumatoid port using a flexor tendon transfer. J Foot Surg flat foot. Arthritis Rheum 3 7 : 4 4 1 - 1 4 6 , 1988. 21. Duchenne GB: Physiology of Motion, translated by 28:154-157, 1989. E.B. Kaplan. J. B. Lippincott, Philadelphia, 1949 50. Miller SJ: Principles of muscle-tendon surgery and tendon transfers, Chapter 23. In Comprehen- (pp. 362-363). sive Textbook of Foot Surgery, edited by E.D. Mc- 22. Ibid. (p. 368). 23. Evjenth O, Hamberg J: Muscle Stretching in Man- Glamry, Vol. 2. Williams & Wilkins, Baltimore, 1987 (pp. 714-752, see p. 739). ual Therapy, A Clinical Manual. Alfta Rehab Ferlag, 51. Moore MP: Shin splints: diagnosis, manage- Alfta, Sweden, 1984 (p. 146). ment, prevention. Postgrad Med 8 3 : 1 9 9 - 2 1 0 , 24. Ferner H, Staubesand J: Sobotta Atlas of Human 1988. Anatomy, Ed. 10, Vol. 2. Urban & Schwarzen- 52. Morimoto I: Notes on architecture of tibialis berg, Baltimore, 1983 (Fig. 464). posterior muscle in man. Kaibogaku Zasshi 58: 25. Ibid. (Fig. 4 6 9 ) . 26. Ibid. (Fig. 473). 74-80, 1983. 27. Ibid. (Figs. 4 7 5 , 476). 53. Netter FH: The Ciba Collection of Medical Illustra- 28. Ibid. (Fig. 500). tions, Vol. 8, Musculoskeletal System. Part I: 29. Gray EG, Basmajian JV: Electromyography and Anatomy, Physiology and Metabolic Disorders. cinematography of leg and foot (\"normal\" and flat) during walking. Anat Rec 161:1-16, 1 9 6 8 . Ciba-Geigy Corporation, Summit, 1987 (p. 98). 30. Green DR, Lepow GM, Smith TF: Pes cavus, 54. Ibid. (p. 102). Chapter 8. In Comprehensive Textbook of Foot Sur- 5 5 . Ibid. (p. 103). gery, edited by E.D. McGlamry, Vol. 1. Williams 56. Ibid. (p. 105). & Wilkins, Baltimore, 1987 (pp. 2 8 7 - 3 2 3 , see p. 57. Ibid. (p. 107). 287). 58. Perry J: The mechanics of walking. A clinical in- terpretation. Phys Ther 4 7 : 7 7 8 - 8 0 1 , 1 9 6 7 . 31. Gutstein M: Diagnosis and treatment of muscu- lar rheumatism. Br J Phys Med 7 : 3 0 2 - 3 2 1 , 1938. 59. Perry J, Ireland ML, Gronley J, et al: Predictive 32. Helal B: Tibialis posterior tendon synovitis and value of manual muscle testing and gait analysis rupture. Acta Orthop Belg 5 5 : 4 5 7 - 4 6 0 , 1989. in normal ankles by dynamic electromyography. 33. Hirsh S, Healey K, Feldman M: Chronic teno- Foot Ankle 6 : 2 5 4 - 2 5 9 , 1 9 8 6 . synovitis of the tibialis posterior tendon and the 60. Rasch PJ, Burke RK: Kinesiology and Applied Anat- use of tenography. J Foot Surg 2 7 : 3 0 6 - 3 0 9 , 1 9 8 8 . omy, Ed. 6. Lea & Febiger, Philadelphia, 1 9 7 8 34. Holmes GB Jr, Cracchiolo A III, Goldner JL, et (pp. 321-323, 330, Table 17-2). al.: Current practices in the management of pos- 61. Rohen JW, Yokochi C: Color Atlas of Anatomy, Ed. terior tibial tendon rupture. Contemp Orthop 20: 2. Igaku-Shoin, New York, 1988 (p. 424). 79-108, 1990. 35. Janda V: Muscle Function Testing. Butterworths, 62. Rorabeck CH: Exertional tibialis posterior com- partment syndrome. Clin Orthop 2 0 8 : 6 1 - 6 4 , London, 1983 (pp. 197-199). 1986. 36. Johnson KA, Strom DE: Tibialis posterior ten- don dysfunction. Clin Orthop 2 3 9 : 1 9 6 - 2 0 6 , 1989. 63. Rorabeck CH, Fowler PJ, Nott L: The results of 37. Kendall FP, McCreary EK: Muscles, Testing and fasciotomy in the management of chronic exer- Function, Ed. 3. Williams & Wilkins, Baltimore, tional compartment syndrome. Am J Sports Med 1983 (p. 142). 16:224-227, 1988. 38. Lee HJ, Bach JR, DeLisa JA: Needle electrode in- 64. Sammarco GJ, DiRaimondo CV: Surgical treat- ment of lateral ankle instability syndrome. Am J sertion into tibialis posterior: a new approach. Sports Med 7 6 : 5 0 1 - 5 1 1 , 1 9 8 8 . Am J Phys Med Rehabil 6 9 : 1 2 6 - 1 2 7 , 1990. 65. Saxena A, O'Brien T, Bunce D: Anatomic dis- 39. Lipsman S, Frankel JP, Count GW: Spontaneous rupture of the tibialis posterior tendon. J Am section of the tibialis posterior muscle and its Podiatr Assoc 7 0 : 3 4 - 3 9 , 1980. correlation to medial tibial stress syndrome. J Foot Surg 2 9 : 1 0 5 - 1 0 8 , 1 9 9 0 . 40. Lockhart RD: Living Anatomy, Ed. 7. Faber & 66. Smith TF: Common pedal prominences, Chap- Faber, London, 1974 (Figs. 136, 141). ter 6. In Comprehensive Textbook of Foot Surgery, edited by E.D. McGlamry, Vol. 1. Williams &
472 Part 3 / Leg, Ankle, and Foot Pain Wilkins, Baltimore, 1987 (pp. 252‐263, see pp. 252, 69. Travell JG and Simons DG: Myofascial Pain and 253). Dysfunction: The Trigger Point Manual. Williams & 67. Soballe K, Kjaersgaard‐Anderson P: Ruptured tibialis Wilkins, Baltimore, 1983. posterior tendon in a closed ankle fracture. Clin Orthop 231:140‐143, 1988. 70. Wiley JP, Clement DB, Doyle DL, et al.: A primary 68. Sutherland DH: An electromyographic study of the care perspective of chronic compartment syndrome of plantar flexors of the ankle in normal walking on the the leg. Phys Sportsmed 75:111‐120, 1987. level. J Bone Joint Surg [Am] 48:66‐71, 1966.
CHAPTER 24 Long Extensors of Toes Extensor Digitorum Longus and Extensor Hallucis Longus \"Muscles of Classic Hammer Toes\" HIGHLIGHTS: REFERRED PAIN from both long in children. Differential diagnoses include other extensor muscles of the toes (extrinsic exten- myofascial pain syndromes with overlapping sors) projects primarily to the dorsum of the foot. pain patterns, and hammer or clawtoes caused Pain referred from trigger points (TrPs) in the by muscle imbalance. ACTIVATION AND PER- extensor digitorum longus concentrates on the PETUATION OF TRIGGER POINTS may result dorsolateral aspect of the foot and may extend from an L 4 - L 5 radiculopathy, an anterior com- nearly to the tips of the middle three toes. Pain partment syndrome, habitually using the muscle referred from TrPs in the extensor hallucis in the lengthened position, and from an acute longus muscle concentrates over the region of stress overload. PATIENT EXAMINATION in- the first metatarsophalangeal joint and may ex- cludes looking for evidence of and testing for tend nearly to the tip of the great toe. ANATOMI- dorsiflexor weakness at the ankle and then, spe- CAL ATTACHMENTS of the extensor digitorum cifically, for extension weakness of the great toe longus are, proximally, to the lateral condyle of and of the four lesser toes. Active resisted or un- the tibia, to the fibula and the interosseus mem- resisted dorsiflexion causes pain when the long brane, and to intermuscular septa. Distally, it extensor muscles of the toes harbor active TrPs. anchors to the middle and distal phalanges of Passive plantar flexion to full range is painful, as the four lesser toes. The extensor hallucis also is resisted extension effort of the corre- longus muscle attaches, proximally, only to the sponding toes and passive flexion of the toes. fibula and interosseus membrane. Distally, it The foot should be examined for abnormalities ends on the distal phalanx of the great toe. in joint play. TRIGGER POINT EXAMINATION FUNCTION: Both long extensors of the toes as- of the extensor digitorum longus requires digital sist in preventing foot slap immediately following palpation of the muscle several centimeters dis- heel-strike, and they help the foot clear the floor tal to the head of the fibula between the tibialis during the swing phase. Function of the exten- anterior and peroneus longus muscles. Exami- sor digitorum longus is critical for normal foot nation of the extensor hallucis longus employs mechanics. The extensor digitorum longus acts digital palpation just distal to the junction of the primarily as a powerful extensor of the proximal middle and distal thirds of the leg anterior to the phalanx of the four lesser toes and also assists fibula. Examination of active TrPs characteristi- dorsiflexion and eversion of the foot. The exten- cally elicits local spot tenderness and referred sor hallucis longus acts primarily to extend the pain from both muscles, but rarely elicits a per- proximal phalanx of the great toe powerfully and ceptible local twitch response. ENTRAPMENT also to assist dorsiflexion and inversion of the of the deep branch of the peroneal nerve can foot. SYMPTOMS produced by myofascial TrPs occur by its impingement against the fibula as it in the long extensors of the toes include persis- passes deep to the taut bands associated with tent pain over the dorsum of the foot, sometimes TrPs in the extensor digitorum longus muscle. foot slap during ambulation, night cramps in the INTERMITTENT COLD WITH STRETCH of all long extensors of the toes, and \"growing pains\" extensors of the toes, both short and long, can 473
474 Part 3 / Leg, Ankle, and Foot Pain be accomplished simultaneously. The clinician treatment techniques are recommended instead applies vapocoolant or ice stroking in downward of TrP injection of the extensor hallucis longus parallel sweeps over the anterior leg and dor- muscle. CORRECTIVE ACTIONS include sum of the foot, including the toes, while plantar avoidance of prolonged severe dorsiflexion or flexing the foot and flexing all toes. Prompt ap- plantar flexion when driving a car or sleeping. plication of moist heat and full active range of Activities that overload the long extensors of the motion complete the procedure. INJECTION of toes, such as wearing spike or high heels or ex- the long extensors of the toes requires full cessive running and jogging, should be avoided. knowledge of the location of the anterior tibial The body and legs must be kept warm, espe- vessels and deep peroneal nerve and careful cially in a cold or drafty environment. orientation of the needle. Generally, alternative 1. REFERRED PAIN Extensor digitorum longus TrPs refer (Fig. 24.1) pain primarily over the dorsum of the foot and toes, nearly to the tips of the middle Active myofascial trigger points (TrPs) are three toes (Fig. 24.1A), as previously re- not unusual in the long extensor muscles ported.62,66 Children present a similar pat- of the toes, which include the extensor tern of pain referred from this muscle.10 digitorum longus and extensor hallucis Sometimes the pain referred from exten- longus muscles. The referred pain pat- sor digitorum longus TrPs concentrates terns of TrPs in these muscles are analo- more strongly at the ankle than over the gous to the referred pain patterns of the dorsum of the foot.65 A spillover pattern extensor digitorum muscle of the hand. may extend halfway up the leg from the Extensor digitorum longus trigger point Extensor hallucis longus trigger point Figure 2 4 . 1 . Pain patterns (bright red) referred from nearly everyone when this trigger point is active. Red trigger points (Xs) commonly observed in the right long stippling indicates occasional spillover of the essential extensor muscles of the toes. The essential pain pat- pattern. A, extensor digitorum longus muscle (light tern (solid bright red) denotes the pain experienced by red). B, extensor hallucis longus muscle (dark red).
Extensor Chapter 24 / Long Extensors of Toes 475 diqitorum Figure 24.2. Attachments of the right longus long extensor muscles of the toes, anter- olateral view. The extensor digitorum longus is medium red, and the extensor hallucis longus is dark red. The superior extensor retinaculum is not pictured. Tibia Fibula Extensor hallucis longus Extensor digitorum Inferior extensor retinaculum longus tendon Extensor hallucis longus tendon ankle toward the TrP (Fig. 24.1A). Jacob- 2. ANATOMICAL ATTACHMENTS AND sen31 reported pain radiating to the an- CONSIDERATIONS terolateral region of the ankle from TrPs (Fig. 24.2) in this muscle. The extensor digitorum longus and exten- Extensor hallucis longus TrPs refer sor hallucis longus muscles (the extrinsic pain primarily to the dorsum of the foot extensors of the toes) share the anterior over the distal aspect of the first metatar- compartment of the leg with the tibialis sal and the base of the great toe with spill- anterior and peroneus tertius muscles.49 over patterns extending downward to the tip of the great toe and upward over the Extensor Digitorum Longus dorsum of the foot and leg, sometimes as (Fig. 24.2) far as the TrP (Fig. 24.16). The extensor digitorum longus is a pen- Lewit35 reported that patients with in- niform muscle that attaches proximally creased tension of the long extensors of to the lateral condyle of the tibia (Fig. the toes experience pain on the anterior 24.2),to the upper three-fourths of the an- aspect of the tibia.
476 Part 3 / Leg, Ankle, and Foot Pain terior surface of the body of the fibula, to middle two-fourths of the medial surface the proximal portion of the interosseus of the fibula, medial to the extensor dig- membrane (above the extensor hallucis itorum longus, and to the interosseus longus) and to intermuscular septa shared membrane. At the ankle, it passes deep to with adjacent muscles in the anterior the superior extensor retinaculum and compartment.15 The part of the muscle through a separate compartment of the in- that anchors to the tibial condyle and ferior extensor retinaculum. Distally, it head of the fibula covers the deep pero- anchors to the base of the distal phalanx neal nerve as it courses around the neck of the great toe. An expansion from the of the fibula to reach the intermuscular medial side of the tendon is usually in- septum. At the ankle, the tendon passes serted into the base of the proximal pha- deep to the superior and inferior extensor lanx.15 retinacula and then divides into four ten- dinous slips that attach distally to the The proximal attachment of the extensor hal- middle and distal phalanges of the four lucis longus is occasionally united with that of the lesser toes. Each tendon receives a fibrous extensor digitorum longus.15 Occasionally, a small expansion from the interossei and lumbri- extensor ossis metatarsi hallucis may run from the cals. The tendon then spreads into an extensor hallucis longus (or from the extensor dig- aponeurosis called the extensor hood, itorum longus or tibialis anterior) through the which covers the dorsal surface of the same compartment deep to the inferior extensor proximal phalanx. It sends one slip to the retinaculum as the extensor hallucis longus.15 It base of the middle phalanx; two collateral ends on the first metatarsal bone. Rarely, a sepa- slips unite and continue on to attach to rate long extensor of the first phalanx of the great toe the dorsal base of the distal phalanx.15 may originate on the tibia or interosseous mem- Duchenne18 describes an extensor dig- brane.68 itorum longus attachment (by means of fi- brous expansions from the plantar surface Supplemental References of the tendons) also to the dorsal surface of the proximal phalanges of the four lesser The front view portrays both the extensor dig- toes. Bardeen8 also describes this attach- itorum longus and extensor hallucis longus in ment to the proximal phalanges; however, their entirety without associated nerves or ves- not all anatomists mention it.15 sels.25,50,61 A similar view shows their tendons and synovial sheaths at the ankle.6,30,45,54,60 Other fig- The part of the extensor digitorum ures show their attachments to the toes in de- longus that ends in a tendon to the sec- T A I L .5 . 2 8 , 4 6 . 5 4 ond toe often forms a distinctly separate muscle belly from the semipennate part Front views portray the relations of the two of the muscle that supplies the remaining muscles to the deep peroneal nerve and to the an- lesser toes.34 The belly of the entire mus- terior tibial artery throughout the leg.4, 51 Deep dis- cle may be more or less completely di- sections with the proximal end of the extensor vided to correspond with the tendons to digitorum longus reflected reveal how sustained individual toes.8 tension in that muscle could entrap the deep pero- neal nerve against the tibia.23,43,52 The arrangement of its tendinous at- tachment to the toes varies considerably. The extensor digitorum longus16 and both long Additional slips may span from a tendon extensors of the toes24, 60 appear in lateral view. to its corresponding metatarsal bone, to the short extensor of the toe, or to one of Cross sections show the relations of these two the interosseus muscles.8,15 muscles to neighboring muscles and to major ves- sels and nerve trunks in 16 serial sections,12 in Extensor Hallucis Longus three sections through the upper, middle, and lower thirds of the leg,27 in two sections through The extensor hallucis longus lies be- the upper and lower thirds of the leg,13 in one sec- tween, and is largely covered by, the tibi- tion just above the middle of the leg,49 and in one alis anterior and the extensor digitorum section through the lower part of the middle third longus muscles. Its tendon emerges to a of the leg.3 superficial position in the lower third of the leg. Proximally, it attaches along the Markings on the bones locate the osseous at- tachments of both muscles in the leg,1,26,41,53 and of the extensor hallucis longus to the distal phalanx of the great toe.7,29,42,53
Chapter 24 / Long Extensors of Toes 477 Photographs reveal the surface skin contours proximal phalanx most powerfully.8,21,32 It also as- sists dorsiflexion and inversion of the foot.8,15,58 produced by the extensor digitorum longus mus- Stimulation of this muscle produced vigorous ex- tension of the proximal phalanx of the great toe cle,14,17 by that muscle's tendon at the ankle,2,37 with weak dorsiflexion and inversion of the foot.19,21 For the extensor hallucis longus to pro- and by the tendons of both muscles at the ankle duce strong extension of the distal phalanx of the great toe, synergistic action of the first dorsal in- and on the dorsum of the foot.\" terosseus muscle is required for firm fixation of its proximal phalanx.19 3. INNERVATION Functions Both the extensor digitorum longus and extensor hallucis longus muscles receive Standing and Ambulation their innervation via deep peroneal nerve branches, which contain fibers from the The extensor hallucis longus was electrically si- fourth and fifth lumbar and first sacral lent during quiet stance, but became active when spinal nerves.15 subjects swayed backwards and also during dor- siflexion of the ankle.9 4. FUNCTION During ambulation, the extensor hallucis longus The extensor digitorum longus and the showed a spike of activity immediately after heel- extensor hallucis longus muscles func- strike, apparently to help control (decelerate) tion as assistants in controlling (deceler- plantar flexion and prevent foot slap. Motor unit ating) the descent of the forefoot to the activity in this muscle and in the extensor dig- floor immediately following heel-strike, itorum longus began shortly before swing phase thereby preventing foot slap. During the and continued throughout swing phase, appar- swing phase of gait, they assist in provid- ently to assist in lifting the forefoot clear of the ing foot-floor clearance. The extensor dig- floor.17,56 Measurement of ground reaction force, itorum longus helps provide pure dor- myoelectric activity, and motion in pronation-su- siflexion of the foot by balancing the pination of the foot in 11 normal adults revealed inversion pull of the tibialis anterior mus- that, when the lateral component of ground reac- cle. The long extensors of the toes also as- tion force was small, the extensor hallucis longus, sist in preventing excessive postural sway the tibialis posterior, and the flexor digitorum in a posterior direction. longus were active.40 The extensor hallucis longus was considered to be active during the midstance The extensor hallucis longus is thought phase in order to allow the foot to adapt to the to help the foot adapt to the ground in ground. walking. Among seven normal subjects, the intensity of The extensor digitorum longus acts to myoelectric activity in the extensor digitorum dorsiflex and evert the foot and to extend longus and the extensor hallucis longus muscles the four lesser toes. The extensor hallucis during slow gait corresponded to manual muscle longus assists in dorsiflexion and inver- testing levels of mostly fair, occasionally fair -, in sion of the foot and extends the great toe. those muscles. During free gait, the myoelectric activity increased slightly to a level corresponding Actions to manual testing of mostly fair, occasionally fair + . During fast gait, the myoelectric activity The extensor digitorum longus powerfully ex- usually corresponded to a manual testing level of fair +.57 tends the proximal phalanx of the four lesser toes, Jumping and Sports Activities and extends the middle and distal phalanges less During a standing two-leg vertical jump, the ex- vigorously.18 It also dorsiflexes and everts the tensor digitorum longus of five normal adults showed a strong peak of EMG activity at the be- foot.8,15,58 Electrical stimulation of this muscle ginning of the upward spring and another at the time of take-off from the ground. Activity resumed caused extension of the proximal phalanx of each shortly before landing and persisted until both feet were again solidly on the ground and stability of the lesser four toes with dorsiflexion, abduction was achieved.33 of the foot, and elevation of its lateral border (eversion).18 Simultaneous electrical stimulation of the tibialis anterior muscle resulted in more vigorous pure dorsiflexion at the ankle; normally, any tendency for abduction or adduction of the foot was balanced out in this test.20 Although the extensor hallucis longus attaches to the distal phalanx of the great toe with a tendi- nous slip to the proximal phalanx, it extends the
478 Part 3 / Leg, Ankle, and Foot Pain The extensor digitorum longus muscle consis- 6. SYMPTOMS tently showed more surface myoelectric activity The chief complaint of patients with TrPs in the long extensors of the toes is usually on the left side than on the right during 13 right- pain on the top of the foot extending to the \"knuckles\" (metatarsophalangeal handed sports activities that included overhand joints). If asked, the patient often merely says that the feet hurt. Frequently, how- throws, underhand throws, tennis strokes, golf ever, patients do not complain spontane- ously about painful feet and when que- swings, and hitting a baseball. Generally, this ried will respond, \"But don't everybody's feet hurt?\". Inquiry is essential because muscle on the right side exhibited a prolonged these individuals have become so accus- tomed to the referred pain and tenderness burst of moderate activity shortly before release in their feet that they think such pain is a normal part of everyone's life. of, or contact with, the ball. The muscle on the left The patient also may complain of foot side sometimes showed a burst of activity preced- slap or weakness of the foot during walk- ing because of a compromised ability to ing contact or release, and always produced a vig- control the descent of the forefoot to the floor following heel-strike. This is likely orous burst following contact or release. The left to happen if the extensor digitorum longus muscle harbors TrPs. When, in ad- muscle also exhibited a crescendo of activity dition, the TrPs in this muscle cause en- trapment of the deep peroneal nerve (see throughout the golf swing.\" No report was located Section 10 in this chapter and page 386 of this volume), symptoms may include that described the activity of the extensor hallucis complete foot-drop due to neurapraxia and weakness of all anterior compartment longus during these activities. muscles. Weakness An intermediate severity of dorsiflex- ion weakness of the foot occurs with TrP Weakness of the extensor digitorum longus allows activity in the extensor hallucis longus muscle also, but without nerve entrap- the foot to assume a more inverted (varus) posi- ment. tion as the tibialis anterior muscle overpowers the Night cramps of the long extensors of the toes are commonly encountered when compensatory effect of the extensor digitorum the muscles have active TrPs. (Chapter 21 of this volume includes an extensive re- longus. In addition, a mild foot drop may develop view of nocturnal leg cramps.) These ex- trinsic extensor muscles of the toes are with inversion, forefoot equinus, and a flexed po- vulnerable to similar cramping when fa- tigued and placed in the shortened posi- sition of the toes.48 tion for a long time. Abnormal Extensor Reflex Response Children and adolescents are likely to complain of \"growing pains\" caused by The abnormal extensor reflex response of the great TrPs that were activated by the stresses of their excessively vigorous locomotor ac- toe, or Babinski response, is associated with ab- tivity. normally vigorous activity, primarily of the exten- Differential Diagnosis sor hallucis longus muscle.9 Pain referred from TrPs in the extensor digitorum longus muscle can easily be 5. FUNCTIONAL (MYOTATIC) UNIT mistaken for pain arising in synovial joints of the tarsal bones.59 The agonists to the long extensors of the toes for their primary function of toe ex- tension are the corresponding two short extensors (intrinsic extensors), namely, the extensors hallucis brevis and dig- itorum brevis. The chief antagonists to toe extension are all of the toe flexors, both short and long (intrinsic and extrinsic). For dorsiflexion of the foot, the primary agonists to the long extensors of the toes are the tibialis anterior and peroneus ter- tius muscles. Antagonists to the foot dor- siflexion action of these two toe extensor muscles are chiefly the gastrocnemius and soleus muscles. For eversion of the foot, the agonists of the extensor digitorum longus are all three peroneal muscles. For inversion of the foot, the extensor hallucis longus is assisted by the tibialis anterior, tibialis posterior, and the two long flexor muscles of the toes.58
Chapter 24 / Long Extensors of Toes 479 Other Myofascial Pain Syndromes may involve the dorsal aspect of the great toe itself. The TrPs in five other muscles refer pain in patterns that could be confused with Hammer Toes and Clawtoes the pattern referred by the extensor dig- itorum longus muscle (Fig. 24.1A). It may The hammer toe can manifest itself in dif- be necessary to examine these muscles for ferent ways, including the classic ham- TrPs to determine which one or ones are mer toe, clawtoe, or mallet toe.32 In the responsible for the pain. The pain re- classic hammer toe (of the four lesser ferred by the peroneus longus and brevis toes), the metatarsophalangeal (MP) joint muscles appears over the lateral malleo- is extended, the proximal interphalangeal lus and more laterally on the dorsum of (IP) joint is flexed, and the distal IP joint the foot (see Fig. 20.1.A). The pain re- is extended, producing a flat \"hammer ferred by TrPs in the third muscle, the head\" at the end. In clawtoes, the MP peroneus tertius, concentrates at and above joints are markedly extended and the the ankle; pain also often extends to the proximal and distal IP joints are fixed in lateral side of the heel below the lateral flexion, producing a claw curvature. In malleolus (see Fig. 20.1B), an area the mallet toe, only the distal IP joint is outside the pattern of the extensor dig- flexed. True clawtoe deformity is often itorum longus. Pain caused by the fourth associated with cavus foot deformity and muscle, the extensor digitorum brevis (see neuromuscular conditions. The clawtoe Fig. 26.1), is the most difficult to distin- deformity tends to create a more severe guish based only on the pain distribution. functional disability than the hammer Pain referred from the extensor digitorum toe.32 brevis centers more proximally on the dorsum of the foot and does not extend These conditions usually develop be- into the toes, the latter projection being cause of muscle imbalance initiated by much more characteristic of the extensor compensatory mechanisms. Three mech- digitorum longus TrPs. Lastly, TrPs of the anisms are identified: flexor stabilization, interossei can also produce toe pain, but flexor substitution, and extensor substitu- the pain is specific to one toe or adjacent tion. The first two mechanisms concern portions of two toes; this TrP pain of in- the long flexor muscles of the toes and are terossei concentrates in the toes rather covered in the next chapter. Extensor sub- than the dorsum of the foot, although con- stitution concerns the extensor digitorum siderable overlap may occur (see Fig. longus muscle.32 27.3A). Extensor substitution can produce both The referred pain from TrPs in two clawtoes and classic hammer toes. This other muscles can easily be confused mechanism is more common than flexor with the referred pain pattern of the ex- substitution, but less common than flexor tensor hallucis longus (Fig. 24.18). The stabilization.32 Extensor substitution pro- pattern referred from the tibialis anterior duces excessive digital contraction dur- muscle (see Fig. 19.1) concentrates far- ing the swing phase of gait. Because the ther distally on the great toe itself, and extensor digitorum longus has a mechani- not so much on the region of the metatar- cal advantage, this overactivity causes a sophalangeal joint at the base of the great functional imbalance with the lumbrical toe. The tibialis anterior pain pattern also muscles. The MP joints are hyperex- concentrates more in the ankle region tended during swing phase and heel- rather than distally over the dorsum of strike, and, as the condition progresses, the foot. Pain referred from the extensor may remain in that position during hallucis brevis (see Fig. 26.1) is felt more weight bearing. in the tarsal region and near the lateral as- pect of the first metatarsal than on the Extensor substitution occurs when the dorsal aspect of the base of the great toe. extensor digitorum longus attempts to Both the extensor hallucis longus and the provide more than its fair share of dor- tibialis anterior referred pain patterns siflexion effort. This muscle does not be- come effective as a dorsiflexor of the foot until it has completed its easier function of extending the MP joint; if the latter
480 Part 3 / Leg, Ankle, and Foot Pain movement is unopposed by adequate defect of the extensor digitorum longus tendon lumbrical action, this extended toe posi- tioning occurs with every step. Any con- sheath distal to the head of the talus. At operation, dition that plantar flexes the forefoot, such as anterior pes cavus or ankle the inferior extensor retinaculum was adherent to equinus, can initiate a vicious cycle of in- creasing distortion of toe position. Pri- the extensor digitorum longus tendon. Lysis and mary lumbrical weakness, or chronically increased tension of the flexor digitorum excision of the adhesions provided relief of the longus muscle (due to spasticity or to shortening of the muscle by taut bands of pain and restored normal muscle function.55 TrPs) can be responsible. A painful fore- foot that causes the individual to lift the A 16-year-old male experienced a closed rup- foot in a flat manner and avoid forefoot pressure at the end of stance phase dis- ture at the musculotendinous junction of the ex- proportionately loads the extensor dig- itorum longus.32 Wearing shoes (espe- tensor hallucis longus muscle during a powerful cially tight ones) appears to be a major contributing factor to disuse atrophy of forced flexion of the great toe against fixed resis- the lumbrical muscles, or to failure of their normal development in childhood. tance while attempting to kick a football. This A case64 of an individual presenting with the may have been a late complication of fracture of symptoms of acute shin splints and loss of the distal tibial shaft with associated compromise strength of only the extensor digitorum longus, of blood supply to the tendon in the region of the with evidence of denervation of the muscle, was tear.47 presented as an example of a partial anterior com- 7. ACTIVATION AND PERPETUATION OF TRIGGER POINTS partment syndrome due to acute overuse of toe ex- Activation tensors on a motorcycle trip. The severe neural Radiculopathy at the L4-L5 level can, but impairment of only one of the four muscles in the does not always, activate and perpetuate TrPs in these long extensor muscles of the anterior compartment raises the question of a pos- toes. The TrPs may also result from trip- ping or falling. They are likely to appear sible entrapment syndrome (see Section 10, fol- following an anterior compartment syn- drome and the associated ischemia of the lowing). The possibility that the muscular over- muscles in that compartment. load activated TrPs in the extensor digitorum For the driver of a car, a steep accelera- tor pedal that maintains the ankle at an longus was apparently not considered. acute angle in dorsiflexion can place the long extensors of the toes in a shortened Tendinitis and Rupture of Tendon position for an extended time. This situa- tion favors the activation of latent TrPs. Hypertrophy or exostosis at the first Similarly, sitting for long periods with metatarsocuneiform joint, due to osteoar- the feet back under a chair with the an- thritis or other causes, may cause foot irri- kles in an extreme dorsiflexed position tation by a shoe and hypertrophy of the can activate TrPs in these long extensors. extensor hallucis longus tendon as it crosses this region. Such chronic micro- On the other hand, excessively trauma to the tendon may also produce stretched-out muscle fibers at a long tendinitis, pain, thinning of the tendon, sarcomere length are weaker than at mid- and possibly rupture.63 length; thus, the stretched-out muscle must work harder to do the same job. For A 28-year-old female suffered rupture of the an- this reason, these extensor muscles are chronically overloaded and, therefore, terior talofibular ligament with partial involve- susceptible to developing TrPs in people who wear high heels. Placing the ankle in ment of the calcaneofibular ligament as the result a strongly plantar flexed position for long periods, as when the accelerator of the car of an acute right foot-inversion injury. Following is nearly parallel to the floor, can have this same weakening effect. Shortened tri- immobilization, the patient had constant pain ceps surae musculature that produces a \"tight\" Achilles tendon and restricts ac- over the dorsal aspect of the midfoot aggravated tive dorsiflexion to less than 10° can chronically overload the long extensors of by resistance to contraction of the extensor dig- itorum longus. Tenogram demonstrated a filling
Chapter 24 / Long Extensors of Toes 481 the toes, inciting the development of TrPs findings in patients with TrPs in this in them.39 muscle. These same tests apply equally well for identifying TrP involvement of In addition, TrPs may be activated by the extensor digitorum longus muscle by excessive jogging or running, unaccus- similarly testing these movements of the tomed walking on uneven ground or in four lesser toes. soft sand, and catching the toes on the ground when kicking a ball. The clinician should examine the pa- tient's foot for abnormalities in joint play. Direct gross trauma to the muscle, stress fractures of the tibia or fibula, and 9. TRIGGER POINT EXAMINATION immobilization after an ankle fracture or (Fig. 24.3) sprain are other causes of TrP activation. The TrPs that result from these acute Usually, digital examination of active overload conditions usually respond well TrPs in the extensor digitorum longus to myofascial therapy. (Fig. 24.3A) elicits local spot tenderness and referred pain in the foot and ankle Perpetuation (pain distribution shown in Fig. 24.1A). Pressure is applied approximately 8 cm (3 Any factor that activates TrPs, when con- in) distal to the level of the fibular head tinued, also perpetuates them. More com- between the tibialis anterior and per- monly, however, one stress activates the oneus longus muscles. At this level, the TrPs and other factors perpetuate them. most proximal part of the extensor hal- lucis longus is deep to and between the Mechanical factors, such as the pro- extensor digitorum longus and the tibialis longed plantar flexed position of the an- anterior muscles.49 Contraction of the ex- kle during sleep, and systemic factors, tensor digitorum longus usually is distin- such as nutritional inadequacies, may be guishable by palpation when the patient responsible for the fact that good initial selectively extends the lesser toes against results with myofascial therapy provide resistance without exerting dorsiflexion ef- only temporary relief (see Chapter 4 in fort at the ankle. Volume l ) . 6 7 Similarly, palpation of active TrPs in 8. PATIENT EXAMINATION the extensor hallucis longus (Fig. 24.38) elicits local tenderness and pain that is During ambulation of the patient, the cli- referred over the dorsum of the forefoot nician should look and listen for foot slap medially in the vicinity of the first MP and should examine heel walking for evi- joint (Fig. 24.16). The examiner usually dence of dorsiflexor weakness. The exten- finds these TrPs slightly distal to the sors of the great toe, of the lesser toes, and junction of the middle and distal thirds of the tibialis anterior muscle are tested sep- the leg anterior to the fibula. In this re- arately to identify the muscle(s) responsi- gion, the extensor hallucis longus may be ble for weakness in dorsiflexion. Marked emerging from between the tibialis ante- weakness of all five toes suggests entrap- rior and the extensor digitorum longus, as ment of the deep peroneal nerve by the the latter becomes tendinous. As the ex- extensor digitorum longus; mild-to-mod- tensor hallucis longus becomes subcuta- erate, ratchety, or \"breakaway\" weakness neous, it lies anterior and adjacent to the suggests only TrP involvement without fibula.27 Contraction of this muscle can significant neurapraxia due to nerve en- usually be distinguished by palpation dis- trapment. tal to the TrP region when the patient se- lectively extends the great toe against re- Macdonald demonstrated experimen- sistance without exerting dorsiflexion ef- tally38 in patients with tenderness of the fort at the ankle. extensor hallucis longus muscle that vol- untary extension of the great toe against Placing either of the long extensor resistance (forceful contraction of the muscles of the toes on slight stretch in- muscle) was painful, but resisted flexion creases the sensitivity of TrP tender- effort was not. Also, passive stretching of ness, makes the taut band stand out this extensor muscle was painful, but pas- with maximum contrast to surrounding sive shortening (passive toe extension) was not painful. We observe these same
482 Part 3 / Leg, Ankle, and Foot Pain Figure 24.3. Palpation of trigger points in the right long extensor muscles of the toes. The proximal X locates the usual region of extensor digitorum longus trig- ger points, and the distal X shows the usual region of extensor hallucis longus trigger points. The dashed line locates the anterior crest of the tibia. The solid circle marks the head of the fibula. A, extensor digitorum longus trigger point. The operator exerts pressure deep in the anterior compartment of the leg lateral to the tibialis anterior muscle. B, extensor hallucis longus trigger point. Examina- tion by flat palpation, slightly distal to the junction of the middle and distal thirds of the leg anterior to the fibula. slack muscle fibers, and enhances the perficial and deep branches of this nerve, local twitch response. Local twitch re- as described in Section 10 of Chapter 20 sponses are much less readily elicited in this volume. When the responsible in the long extensors of the toes than in TrPs in the extensor digitorum longus are the peroneus longus and tibialis ante- inactivated, the neurapraxia due to en- rior muscles and are less easily elicited trapment of the deep peroneal nerve may in the toe extensors than in the long ex- disappear within 5 or 10 minutes with re- tensors of the fingers. turn of strength of all four of the anterior compartment muscles that it innervates; 10. ENTRAPMENTS namely, the tibialis anterior, extensor hal- lucis longus, extensor digitorum longus, The deep peroneal nerve enters the ante- and peroneus tertius. rior compartment of the leg by passing first deep to the peroneus longus in the The patient is often mystified by this company of the superficial peroneal method of producing recovery, especially nerve and then continues alone deep to when entrapment has caused severe the extensor digitorum longus muscle neurapraxia of the anterior compartment ( s e e Fig. 20.9).52 Here, only the deep pero- muscles with serious foot-drop. The pa- neal nerve is subject to impingement tient wonders how an injection of a local against the fibula by the taut bands of anesthetic like procaine can cause the TrPs in the extensor digitorum longus muscle to become stronger, and instead muscle. Similar taut bands in the per- expects the anesthetic to \"put the nerve to oneus longus muscle can entrap both su- sleep\" and cause weakness. The clinician then explains to the patient the mechan-
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