Chapter 20 / Peroneal Muscles 383 heads, which may also carry additional weight. and insole. If the patient already has favorite These calluses further aggravate abnormal weight shoes that are too tight, a shoe repairman can of- distribution on the metatarsal heads at the end of ten stretch a leather vamp (part covering the in- stance phase. step and toes) overnight. Other calluses also tend to develop: on the me- 3. The sole should be flexible at the heads of the dial side of the great toe, toward the end of this metatarsals. Unless the sole of a shoe is stiff be- toe; medially beside the head of the first metatar- cause it is new, the examiner should be able to sal; along the lateral border of the sole of the foot bend it readily with hand pressure. A rigid anteriorly; and, sometimes, on the lateral side of wooden sole is obviously unsatisfactory in this re- the fifth metatarsal (Fig. 20.7). spect. Ice skates pose a similar problem. Duchenne31 observed that patients with paraly- 4. The heel counter should be firm and the shoe sis of only the peroneus longus muscle presented should fit well. Heel space that is excessively primarily with painful calluses on the lateral bor- wide allows the heel of the foot to wallow loosely der of the sole of the foot. This reinforces the im- from side to side inside the shoe. This, in turn, pression that when patients develop TrPs that in- lets the entire foot turn and slip sideways in the hibit the peroneus longus and weaken its func- shoe, which requires additional stabilization by tion, they eventually develop calluses. The the muscles and can cause blisters and Achilles presence of these lateral calluses indicates abnor- tendon irritation. This problem is characteristic of mal lateral forces that rub the feet against the side women's sandal-type shoes, especially if the of the shoe. Callus formation along both sides of shoes have high heels. A sufficiently thick, firm the foot may also depend on shoe tightness. The foam or felt pad added inside a shoe along the callus at the medial side of the first metatarsal sides of the heel prevents such traumatic move- head indicates one source of bunions that, in its ment. early stages, is correctable without surgery by modifying the shoes. 5. A critical observation is excessive wear on the outer side of the heel and on the inner edge of the Shoe Examination sole. Some lateral heel wear is normal. The exces- sive wear pattern develops because of excessive Inappropriate shoes aggravate the mechanical in- inversion and then excessive eversion of the foot stability induced by the Morton foot structure. during stance phase (side to side rocking in the Even a proper correction can cause additional frontal plane). Patients with more severe hyper- trouble in the wrong style of shoe. Examination of pronation may show only excessive medial heel the shoes should include at least the following and sole wear patterns. Shoes with a worn heel considerations: aggravate mechanical imbalance of the foot and should be replaced and the imbalance corrected. 1. The shoe should have a straight last to provide The patient may need to consult a competent po- maximum support under the arch. With the shoes diatrist. placed beside each other positioned as the patient wears them, the medial sides should touch each 6. The heel of the shoe should be flat and not other from heel to near the toe. The toes should pitched in any direction as a correction for une- not be pointed and should not curve away from ven wear caused by the Morton foot structure. each other. Such pointed shoes forcibly abduct Some practitioners add a wedge to the heel to the great toe, cramp the metatarsal heads, exagger- raise its medial side, which may help when the ate mechanical imbalance, and contribute to bun- patient is standing still, but it aggravates mechani- ion formation in men and women. cal imbalance when the patient walks. Good arch support is needed. 2. The cap (or toe box) of the shoe covers the toes and metatarsal heads. The vertical height of 9. TRIGGER POINT EXAMINATION the cap should provide ample room for movement (Fig. 20.8) of the toes and metatarsal heads with shoe inserts in place. If the cap is tight during ambulation, the For examination of the peroneal muscles patient loses normal toe movement; a pad inserted for TrPs, the patient lies supine with the for compensation of a Morton foot structure often foot free to move while the other limb makes the cap tighter and aggravates symptoms by (not being examined) is covered to pre- crowding the toes. For this reason, patients vent chilling of the patient (Fig. 20.8). should take a foam insole with them when buying The most common TrP location in the new shoes and slip the insole into each new shoe peroneus longus muscle (Fig. 20.1A and when trying it on the larger foot to ensure ade- proximal point of palpation in Fig. 20.8) quate room for addition of the first metatarsal pad
384 Part 3 / Leg, Ankle, and Foot Pain Figure 20.8. Palpation of trigger points in the right the foot indicates its movement due to a local twitch peroneus longus and brevis muscles. The solid circle marks the head of the fibula. The outlined hand illus- response elicited by snapping palpation across the trigger point in the peroneus longus muscle. The fully trates palpation of a trigger point in the peroneus rendered hand illustrates palpation of a trigger point in longus muscle against the fibula. The dotted outline of the peroneus brevis muscle. is about 2-4 cm (approximately an inch ther side of, and deep to, the peroneus or slightly more) distal to the head of the longus tendon near the junction of the fibula over the shaft of the fibula. Taut middle and lower thirds of the leg. These bands at this TrP location are clearly de- TrPs also are palpable against the shaft of lineated by palpation against the underly- the fibula. Obvious LTRs are more diffi- ing bone. This firm foundation makes it cult to elicit from this muscle than from easy to elicit a local twitch response (LTR) the peroneus longus, but the visible re- in the peroneus longus muscle by snap- sponse of the foot is essentially the same. ping palpation. The transient twitch Pressure on active TrPs in either of these causes the foot to swing outward and muscles characteristically elicits referred down, as indicated by the outlined foot in pain in, behind, and distal to the lateral Figure 20.8. The common peroneal nerve malleolus, in which case this area also ex- crosses diagonally over the neck of the hibits referred tenderness. fibula just below the fibular head and has a cordlike consistency. The nerve is dis- TrPs in the peroneus tertius muscle tinguished from a taut band by its proxi- (see Fig. 20.1B) are palpable slightly dis- mal position and a course running across tal and anterior to peroneus brevis TrPs, the muscle rather than running the length and proximal and anterior to the lateral of the muscle nearly parallel to the shaft malleolus. The tendon of this muscle of the fibula.70 Excessive pressure on the stands out and is readily palpable in the nerve may cause painful tingling sensa- anterolateral aspect of the ankle and foot tions over the lateral side of the leg and (lateral to the extensor digitorum longus the foot. tendons) when the seated patient at- tempts to evert the foot by lifting the This location of peroneus longus TrPs fifth metatarsal from the floor. Taut corresponds to the location where Lange58 bands in this muscle are often difficult found myogelosis of the peroneal mus- to delineate by palpation, but pressure cles. on the sensitive active TrP usually refers pain to the anterolateral ankle and some- TrPs in the peroneus brevis muscle times to the lateral side of the heel (see (Fig. 20.1A and the distal point of palpa- Fig. 20.16). tion in Fig. 20.8) are usually found on ei-
Chapter 20 / Peroneal Muscles 385 10. ENTRAPMENTS Numbness and tingling caused by en- (Fig. 20.9) trapment of the common peroneal nerve (Fig. 20.9B) appear on the dorsum of the Section 6, under Differential Diagnosis, foot in the triangular area between the first reviews the symptoms caused by entrap- and second toes. This specific patch of ment of the common peroneal nerve and skin area is supplied only by the deep and its branches, the superficial and deep per- superficial peroneal nerves,54 whereas the oneal nerves. surrounding dorsum of the foot is also supplied by other nerves. An opening at the proximal attachment of the peroneus longus muscle provides The deep peroneal nerve may also be passage for the peroneal nerves. This entrapped against the fibula by the taut opening lies between the proximal fibers bands of TrPs in the extensor digitorum and tendon of the peroneus longus and longus muscle (Fig. 20.9A). This neuro- the neck of the fibula. The opening is de- logical distribution of pain due to entrap- limited by a fibrous edge that takes the ment is distinguishable from the pattern form of the letter \" J \" on the left leg and a of aching pain referred to the ankle region reversed \" J \" on the right. The superficial by TrPs in the peroneus longus or brevis and deep peroneal nerves bend over the muscles (Fig. 20.1A). bottom of the \"J\"; the superficial peroneal nerve bends most sharply. In the anatomi- Another potential source of compres- cal specimen and at surgery, inverting sion of the common peroneal nerve or its and plantar flexing the foot pulled the branches is the use of a pneumatic stock- nerves taut against this fascial edge.56 ing for \"mechanical anti-thrombophlebi- tis therapy.\" Symptoms of nerve impair- Neurolysis of the peroneal nerve as it passed ment have been observed in several older patients following use of this pneumatic deep to this sharp fibrous edge at the origin of the stocking.2 peroneus longus muscle relieved signs and symp- 11. ASSOCIATED TRIGGER POINTS toms of peroneal nerve compression neuropathy The peroneus longus is almost always in- volved when either of the other two pero- in seven of eight patients.60 The symptoms were neal muscles harbors TrPs. Not surpris- ingly, the muscle that most commonly de- initiated by vigorous exercise, but the report did velops secondary TrPs associated with TrP-weakened peroneal muscles is their not mention whether myofascial TrPs of the per- prime agonist for eversion, the extensor digitorum longus. The fact that the exten- oneus longus contributed to the symptoms, partic- sor digitorum longus also serves as a prime antagonist to the plantar flexion ac- ularly in the patient for whom neurolysis was in- tion of the peroneus longus can account for the likelihood of both muscles devel- effective. oping TrPs. The chronic tension of taut bands in the involved muscle overloads Taut bands caused by TrPs in the per- its antagonist. Peroneus longus TrPs are oneus longus muscle increase the tension also likely to occur in association with of the muscle and can cause entrapment tibialis posterior TrPs; these two muscles of the common peroneal nerve and/or the are specific antagonists in regard to inver- superficial and deep peroneal100 nerves, if sion-eversion, but are agonistic in regard the nerve branches far enough proximally to plantar flexion and to stabilizing the (Fig. 20.9A). The nerve compression may weight-bearing foot. occur against the fibula, or it may result from strangulation of the nerve by muscle Although the peroneus longus and tension on the bands of fascia that sur- peroneus brevis are weak assistants to round the nerve.49 The compression of the prime plantar flexors, TrPs in the motor fibers in the common peroneal powerful gastrocnemius and soleus nerve or in the deep peroneal nerve by muscles are not likely to induce prob- taut bands in the peroneus longus muscle lems in the peroneal muscles. Nor is can cause significant foot drop.93 94 Foot drop and changes in sensation caused by entrapment of the peroneal nerve may re- sult from residual peroneal TrPs that originated during a radiculopathy that was later resolved.
386 Part 3 / Leg, Ankle, and Foot Pain Peroneus longus Patella (cut and reflected) Common peroneal Tibialis anterior nerve Extensor digitorum longus Deep peroneal nerve Tibia Deep peroneal nerve Superficial peroneal nerve Extensor hallucis longus Cut edge of Peroneus longus (cut) superficial fascia Peroneus brevis Fibula Entrapment numbness Extensor digitorum longus B Superficial peroneal A nerve compress the nerve and cause neurapraxia. B, the Medial dorsal zone of entrapment numbness (Zs) due to taut trigger cutaneous nerve point bands in the peroneus longus muscle occupies the space between the first and second toes dorsally. Intermediate dorsal The skin of this part of the foot is innervated exclu- cutaneous nerve sively by branches of both the deep and superficial Deep peroneal nerve peroneal nerves. The reversed \" J \" entrapment struc- ture and the peroneus tertius are not shown here. Figure 20.9. Entrapment of the common, deep or superficial peroneal nerve. A, by a tense peroneus longus muscle (dark red), which is reflected. Entrap- ment of the deep peroneal nerve can be caused also by a tense extensor digitorum longus muscle (medium red). Both the deep and superficial branches of the peroneal nerve pass between the peroneus longus muscle and the underlying fibula where taut bands as- sociated with trigger points in the peroneus longus can any function of the triceps surae likely 12. INTERMITTENT COLD WITH to be compromised because of TrPs in STRETCH the peroneal muscles. (Fig. 20.10) Anterior gluteus minimus TrPs refer The use of ice for applying intermittent pain to the lateral aspect of the leg and cold with stretch is explained on page 9 can induce satellite TrPs in the peroneal of this volume and the use of vapocoolant muscles. spray with stretch is detailed on pages 6 7 - 7 4 of Volume l . 1 0 2 Techniques that The extensor digitorum longus and per- augment relaxation and stretch are re- oneus tertius muscles work closely to- viewed on pages 10-11 and alternative gether as agonists and TrPs in one can in- duce secondary TrPs in the other.
Chapter 20 / Peroneal Muscles 387 Figure 20.10. Stretch position and ice or vapocoolant spray pattern (thin ar- rows) for trigger points (Xs) in the per- oneus longus and peroneus brevis mus- cles. The solid circle marks the fibular head. The stretch movement combines full inversion and dorsiflexion to stretch these muscles. Stretch of the peroneus tertius (not shown) combines inversion and plantar flexion with an additional an- terior (medial) sweep of intermittent cold over the skin covering the peroneus ter- tius muscle. treatment methods on pages 9-11 of this postisometric relaxation, the patient in- volume. It is important to avoid stretch- hales and actively attempts gentle ever- ing to their full range of motion those sion and dorsiflexion against isometric re- muscles that cross hypermobile joints. sistance supplied by the clinician. As the patient then slowly exhales and relaxes, Release of TrP tension in the peroneal the clinician applies sweeps of the ice or muscles by intermittent cold with stretch vapocoolant spray in the pattern illus- begins by making the supine patient com- trated (Fig. 20.10) and takes up any slack fortable and fully relaxed on the treat- that develops in the peroneus tertius ment table. Several slow parallel sweeps muscle by maintaining a slow steady pull of ice or vapocoolant downward over the toward inversion and plantar flexion. In anterolateral aspect of the leg, ankle, and this stretch position, adding passive flex- foot (Fig. 20.10) help inhibit stretch re- ion of the toes also stretches the extensor flexes prior to and during passive length- digitorum longus, which requires sweeps ening of the shortened muscle(s). The of the coolant that include the dorsum of sweeps of coolant should cover the skin the foot and toes (see Chapter 24). over all three peroneal muscles and their referred pain patterns. To prevent a reactive cramp from de- veloping in the tibialis anterior muscle, To release TrP tightness of the per- tension in it should be released promptly oneus longus and peroneus brevis, the by intermittent cold with stretch. The cli- clinician applies the ice or vapocoolant nician passively stretches the tibialis an- downward to cover those muscles and is terior by eversion and plantar flexion of careful to include the areas behind the the foot (see Fig. 19.5). lateral malleolus and on the foot laterally where pain is usually referred. After fully Following the procedures described inverting and adducting the foot, the cli- previously, a moist heating pad rewarms nician then dorsiflexes it within the limit the skin that was exposed to intermittent of comfort.93 (Vapocoolant application is cold, and the patient performs several illustrated in Fig. 20.10). As the patient repetitions of active range of motion inhales, the clinician resists gentle iso- slowly to the fully lengthened and fully metric contraction of the peroneus longus shortened positions of the treated mus- and peroneus brevis muscles. The patient cles. The Peroneal Self-stretch Exercise slowly exhales and relaxes as the clini- (see Section 14 of this chapter) performed cian takes up any slack that develops, daily at home helps to prevent recur- moving the foot gently into dorsiflexion rences. and inversion, while again applying par- allel sweeps of the coolant. The peroneus longus muscle and its skin representation are well suited for the To lengthen the peroneus tertius, the use of ice instead of a vapocoolant (see foot is then moved from dorsiflexion to Chapter 2), for stripping massage,104 or for plantar flexion while maintaining inver- ischemic compression103 against the fib- sion. Combining deep breathing with ula to release the TrPs.
388 Part 3 / Leg, Ankle, and Foot Pain Figure 20.11. Injection of trigger points in the right peroneal muscles. The solid circle marks the head of the fibula. Note the pillow between the knees that ex- tends to the ankles so that it supports the leg being injected. A, peroneus longus trigger-point injection near, but distal, to the course of the common pero- neal nerve that crosses the fibula just below the fibular head. The needle is di- rected toward the underlying bone. B, peroneus brevis trigger-point injection, posterolateral approach, near the junc- tion of the middle and lower thirds of the leg on either side of and deep to the ten- don of the peroneus longus muscle. Evjenth and Hamberg33 illustrate another tech- 15 or 20 minutes as the anesthetic effect of the 0.5% procaine fades. nique for fully inverting the foot in dorsiflexion to Before injecting the peroneus longus stretch the peroneus longus and peroneus brevis TrP, the clinician should first locate the common peroneal nerve by palpation be- muscles and a technique for fully inverting and hind the fibular head. If tapping over the nerve where it passes under the peroneus plantar flexing the foot to stretch the peroneus ter- longus muscle (not on the TrP) sets off tingling of the foot in the nerve's distribu- tius. tion (Tinel's sign), the nerve is probably suffering entrapment at that point. 13. INJECTION AND STRETCH (Fig. 20.11) During injection of TrPs in the per- oneus longus muscle, a pillow separates A detailed description of the technique the knees of the patient, who lies com- for injection and stretch of any muscle ap- fortably on the side with the treatment pears on pages 74-86 in Volume l . 1 0 2 side uppermost (Fig. 20.11A). In a cool room, a blanket or sheet covers exposed Peroneus longus TrPs usually occur skin above the knee to prevent chilling about 2-4 cm distal to the head of the fib- of the patient. Flat palpation of the per- ula; this TrP location may be only 1 cm oneus longus muscle against the fibula (less than /1 2 in) from the common pero- clearly delineates the taut band and pre- neal nerve as it crosses the fibula diago- cisely localizes the spot of maximum nally just below the fibular head (Fig. TrP tenderness in the band. With gloves 20.9). Ordinarily, TrP injection does not on, a 10-mL hypodermic syringe is filled cause a nerve block, but the TrP may be with 0.5% solution of procaine in iso- so close that sometimes the local anes- tonic saline. The skin is cleansed with thetic solution spreads as far as the nerve an alcohol swab and can be sprayed (Fig. 20.11A). It is wise to warn patients with vapocoolant (without frosting the prior to injection that the foot may \"go to sleep\" briefly if there is any \"spillover\" of the anesthetic solution and to reassure them that the foot will \"wake up\" within
Chapter 20 / Peroneal Muscles 389 skin) to cold-anesthetize the cutaneous plied promptly over the treated muscles area of needle entry. The clinician in- helps minimize postinjection soreness. serts the 22-gauge, 37-mm (11/2-in) nee- Then, several cycles of slow active dle into the TrP localized between the range of motion to the fully shortened fingers by directing the needle nearly and to the fully lengthened positions straight downward toward the fibula to help restore promptly the muscle's nor- avoid accidentally encountering the mal range and function. The Peroneal common peroneal nerve or its branches. Self-stretch Exercise (see next section) The TrP often lies close to the bone. In performed daily at home helps greatly addition to the usual jump sign of the to prevent recurrences. patient in response to the sharp pain caused by impaling the TrP with the Baker14 reported a 14-year-old girl with a per- needle, the clinician feels the LTR and often sees movement of the foot due to oneus longus TrP that produced pain and instabil- the LTR (Fig. 20.8, outlined foot). At the same time, the patient usually reports ity during local gymnastics on the balance beam. pain felt in the predictable reference zone of the TrP, which concentrates over Injection of the active TrP relieved the pain and the lateral malleolus. Pain projected by the nerve, however, centers on the dor- instability; she was then able to win the local bal- sum of the foot in the region proximal to the great toe. If palpation reveals a resid- ance beam competition. ual TrP close to the main one, it too must be injected. Following TrP injec- 14. CORRECTIVE ACTIONS tion, the muscle should be passively (Figs. 20.12-20.15) lengthened during intermittent cold ap- plication. Body Mechanics and Corrections (Figs. 20.12-20.14) The procedure for injecting the per- oneus brevis is similar to the one de- Morton Foot Structure scribed previously, except that the TrPs are more distal, usually near the junction If the patient with a Morton foot structure of the middle and distal thirds of the leg has no calluses and no peroneus longus (Figs. 20.1A and 20.11B). The needle ap- TrPs with local twitch responses, a first proaches the muscle from the postero- metatarsal pad may not be required, but lateral direction, passing deep to the per- the added support might be good preven- oneus longus tendon. This injection tive medicine. However, in the absence of should cause no concern about producing calluses, there is a possibility that the ses- a peroneal nerve block. amoid bones in the tendon of the flexor hallucis brevis muscle under the short Injection of peroneus tertius TrPs, first metatarsal head (see Fig. 27.4S) may which are somewhat distal and anterior provide the necessary support. On the to peroneus brevis TrPs (Fig. 20.1B), is other hand, to manage a pain complaint similar to that described for the peroneus of peroneal origin, the Morton foot struc- brevis muscle. A cross section at the level ture usually requires correction. of the junction of the middle and lower thirds of the leg (see Fig. 19.3) shows that The principle in correcting for the the safest and most direct approach to the symptomatic Morton foot structure is to peroneus tertius is through the skin over- equalize the forces between the relatively lying the muscle, with the needle di- long second and the short first metatarsal rected toward the fibula. This avoids the bones during toe-off by adding one, some- superficial peroneal nerve overlying the times two, thin layers of a supporting pad peroneus brevis muscle, and stays well of firm adhesive felt under the first meta- clear of the deep peroneal nerve and ante- tarsal head.75,76,84 A sole insert cut as illus- rior tibial vessels on the interosseous trated in Figure 20.12A facilitates accu- membrane. rate placement of the pad. In this way, one insert can serve to correct several Following injection and passive mus- shoes. On the medial side of the foot, the cle lengthening, a moist heating pad ap- insert should extend beneath the first metatarsal head, almost as far as the in- terphalangeal joint of the great toe. The end should coincide with the distal crease of the shoe (Fig. 20.13), about 1 cm
390 Part 3 / Leg, Ankle, and Foot Pain Felt support Figure 20.12. Modification of a shoe insert to correct (crease of the big toe). B, addition of an adhesive felt for the Morton foot structure (short first, long second support beneath head of the first metatarsal. C, proper metatarsal bones) by padding under the first metatar- fit of the insert against the sole of the foot; the pad is sal head. A, removal of toe portion of the sole insert to located beneath only the first metatarsal head. The extend support only under the first metatarsal head. solid circle marks the head of the second metatarsal The lateral side of the sole insert should not extend bone in the midline of the foot, which must nof be sup- under the second metatarsal head, and the insert ported by the first metatarsal pad. should reach to the end of the first metatarsal bone Figure 20.13. Proper placement of a Distal crease Position of head modified sole insert inside the shoe to of shoe of long 2nd compensate for the Morton foot structure (short first, long second metatarsal Felt support metatarsal bone bones). The end of the first metatarsal attached to pad reaches precisely to the distal underside of Modified sole crease of the shoe, as identified by the sole insert Insert arrow and thumbnail. The felt pad can be fixed to the underside of a foam sole insert cut as shown. The solid circle in the middle of the sole at the distal crease locates the head of the long second met- atarsal bone. The felt pad transfers weight from the second to the first meta- tarsal head, placing the foot on a tripod base, instead of on a straight-line base through the second metatarsal. (3/8 in) beyond the metatarsophalangeal The felt pad can be attached to the under side of joint (Fig. 20.12C). The lateral part of the the sole insert (Fig. 20.126) through the use of ei- cut insert should end just short of the lat- ther adhesive felt or an additional adhesive such eral four metatarsal heads so that it adds as double-sticky carpet tape. The felt pad should no support beneath these bones when cover the area under the head of the first metatar- placed in the shoe.
Chapter 20 / Peroneal Muscles 391 Figure 20.14. A \"Flying Dutchman\" wedge for lasting correction of the short first, long second metatarsal bones (Morton foot structure) is outlined in red. The wedge is inserted by a shoe repair- man into the sole of the shoe between the layers of leather, under the head of the first metatarsal. The dotted lines show the wedge insert in the sole. The finger points to the distal crease of the shoe, which marks the end of the full thickness of the wedge (1/8 inch, inner edge). This permanent correction solves the problems of felt pads wearing thin and falling out, of the cap of the shoe be- ing too tight to permit insertion of the support inside the shoe, and of ensuring accurate placement of the felt pad, as in a high boot. sal, extending to the inner (medial) side of the additional layer of felt added to it after a period of shoe, but not under any part of the second metatar- use. sal head. The pad should extend over the end of the first metatarsal head so that it adds support at With inactivation of the peroneal TrPs and res- toe-off, placing the foot on a tripod base, but it toration of the exercise tolerance of these muscles, should not extend under the distal phalanx of the often less padding is required, but complete elimi- great toe. The insert assembly can be held against nation of the padding makes the muscles prone to the foot (Fig. 20.12C) to ensure that the pad covers reactivation of TrPs. all of the first metatarsal head and none of the sec- ond metatarsal head. Lateral displacement of the On return visits, the patient's shoes should be metatarsal pad only a millimeter or two can make checked for the metatarsal-pad correction. The a significant difference in effectiveness. Since the pads can fall out or slide around in the shoe and Morton foot structure is usually (but not always) may be forgotten when the patient changes shoes bilateral, ordinarily both shoes should be cor- or buys a new pair. Recurrence of peroneal myo- rected. fascial pain symptoms after many months of relief is often due to loss of adequate shoe correction. The sole insert must be wide enough to prevent its slipping sideways. The insert is ineffective if it A permanent \"Flying Dutchman\" correction slides laterally inside the shoe, partly underneath (Fig. 20.14) requires no maintenance and cannot the second metatarsal head. For adequate width, a be \"forgotten\" when shoes are changed. To make woman should buy the male size insert. If she this correction, a shoe repairman inserts a leather wears a size 10 shoe, she should purchase a man's wedge, with the thick edge medially, 3-mm (1/8-in) size 10 sole insert. Similarly, a man who wears a thick at the inner (medial) edge, between layers of size 10 shoe should purchase a size 12 man's in- the leather sole underneath the head of the first sert. The excess length of the insole must be metatarsal. For women's shoes in which the sole trimmed at the heel. does not have at least two layers of leather, as usu- ally found in men's shoes, the \"Flying Dutchman\" This assembly fits into the shoe as shown in can be placed between the existing sole and an Figure 20.13. The patient should try on the shoe added thin rubber sole. Glue-on rubber soles for and test the insert for comfort, paying special at- home use are no longer generally available, but tention to any discomfort during ambulation. The shoe repairmen have thin black rubber half-soles head of the second metatarsal should feel com- suitable for the purpose. pletely free of pressure. Badly worn shoe heels should be replaced or a This is a relatively temporary correction. The metal cleat or rubber tap added over the worn felt becomes compressed and the insert may wear part. Use of the sole insert with a corrective first out after several months of use. Even if the foam metatarsal pad usually ends or greatly reduces the insole does not need replacement, it may need an excessive lateral heel-medial sole pattern of shoe wear. Patients with just the Morton foot structure need both a first metatarsal pad and a flat heel. Ad-
392 Part 3 / Leg, Ankle, and Foot Pain dition of a pad under the shafts of the middle once were snug but comfortable are now three2 or all five76 metatarsals may also be helpful. too tight, they should be discarded. If a patient with a short first metatarsal bone Socks that have tight elastic at the top walks with the toes in rather than the usual posi- and leave an indented ring in the skin tion of slight out-toeing, the first metatarsal pads should be replaced or the elastic slack- for correction of the Morton foot structure may ened. A hot iron can be used to release prove ineffective. For all individuals, and for the elastic. The patient should buy hose these patients especially, foot problems may be snug enough to stay up without constrict- aggravated by the patient's heel fitting loosely in a ing elastic bands. shoe heel that is too wide. Adding felt padding to the inside of the shoe along the sides of the heel Corrective Posture and Activities usually corrects the problem. Adhesive pads for this purpose can be found in some shoe stores, Shoes that provide good arch and foot and the correction can be made when the shoe is support, such as some sneakers, jogging bought. shoes, and boots that are snug, effectively reduce strain on the peroneal muscles, Sometimes a patient with a Morton foot struc- thus making specific TrP therapy more ef- ture is already using a metatarsal support that fective. High heels and spike heels should seems to have helped. The support may be re- be avoided. tained but only if it does not extend under the head of the second metatarsal. If the support is too For correction of underthigh compres- short, a first metatarsal pad may be added to sion caused by too high a chair seat, pos- lengthen it. Morton75 recommended both correc- sible solutions include a footstool to raise tions. the feet, shortening of the chair legs, or tilting the seat bottom downward at the Corrective orthoses can be constructed by com- front. petent podiatrists or physical therapists who are aware of the principles outlined above. The patient with TrPs and weakness of the peroneus longus and peroneus brevis The clinician should insist that the patient muscles should avoid walking on a bring all pairs of shoes for evaluation and correc- slanted sidewalk or running on a laterally tion. Each pair may present a different problem slanted track, which contributes to over- for correction. With the Morton foot structure, pa- load of those muscles. tients may prefer to walk in their bare feet or bed- room slippers. Bedroom slippers and sandals with Corrective Exercises rigid soles should be discarded. (Fig. 20.15) Other Corrections The Peroneal Self-stretch Exercise for the peroneus longus and peroneus brevis Patients with other foot types or struc- muscles is more effective if performed in tural deviations (see Chapters 26 and 27 a warm bath or hot tub with circulating of this volume) need appropriate proce- water (Fig. 20.15). Gentle passive stretch dures and shoe modification to provide of the peroneus longus and peroneus support, comfort, and facilitation of dy- brevis muscles results when the patient namic balance. grasps the forefoot, fully inverts and ad- ducts it, and then pulls it upward toward An ischial (butt) lift (see Chapter 4 of dorsiflexion. Postisometric relaxation can this volume) corrects a small hemipelvis facilitate painless stretch; the patient uses and eliminates or reduces at least one one hand to stabilize the leg just above need to cross the legs. the ankle, and uses the other hand to re- sist an active effort to evert and plantar Shoes with a narrow pointed toe and flex the foot gently while slowly taking in tight cap should be avoided. People who a deep breath. Then, while exhaling walk barefoot are much less likely to de- slowly and fully relaxing the leg and foot, velop bunions than are those who wear the patient takes up any slack that devel- tight shoes. Additional pertinent informa- ops by maintaining a steady pull toward tion regarding shoes is found in Section 8 inversion and dorsiflexion. After a pause, of this chapter. this cycle should be repeated until no fur- As people become older, their feet may spread and tend to swell. If old shoes that
Chapter 20 / Peroneal Muscles 393 Figure 20.15. Passive self-stretch ex- ercise of the peroneus longus and per- oneus brevis muscles, patient seated in a tub of warm water. The arrow identifies the direction of pull: inversion first with plantar flexion, then dorsiflexion of the fully inverted foot. This stretch can be ef- fectively combined with postisometric re- laxation. ther gain in the range of inversion and muscle showed an active TrP that, on palpation, dorsiflexion occurs. referred pain down to the lateral malleolus and to the adjacent lateral region of the foot. Bilaterally, For patients able to handle the addi- the patient had the Morton foot structure and tional complexity, further gains may be large bunions. realized by voluntarily trying to invert and dorsiflex the foot while using the The active TrP in the right peroneus longus hand to assist moving it in the same di- muscle was injected with 0.5% procaine solution, rection. This contraction activates antago- which evoked its referred pattern of pain with no nists of the peroneus longus and per- evidence of contact with the common peroneal oneus brevis muscles, reciprocally inhib- nerve; 24 hours later, the skin sensation was nor- iting them and thereby increasing their mal and weakness on extension of the great toe relaxation and tolerance to stretch. had markedly diminished. The shoe was cor- rected by insertion of a first metatarsal pad, and The peroneus longus depresses the first the accelerator pedal was lubricated. metatarsal for weight bearing, and its co- contraction with the tibialis posterior She had no further recurrence of her peroneus helps to support the medial arch in run- longus syndrome. She kept the accelerator pedal ners who have hyperpronating feet and well lubricated, and used the first metatarsal pad the Morton foot structure. In addition to a in all her shoes. The patient continued to live a metatarsal pad for these individuals, exer- very active life for more than 20 years. cises that progressively increase aerobic capacity and endurance of the peroneus Case 20.2 longus and the tibialis posterior increase (Seen by J. G. Travell, M.D.) their tolerance for running.2 Six months before he was first seen in July, the 15. CASE REPORTS patient, a healthy middle-aged male, had severe left-sided low back pain and the classical signs of Case 20.1 lumbar disc protrusion that included neurological deficit, complete foot drop, loss of skin sensation (Seen by J. G. Travell, M.D.) between the first and second toes, and constant severe pain. A myelogram revealed a defect so A female pediatrician in her mid-fifties drove large that a tumor was suspected. In January, sur- gery had revealed a ruptured herniated disc. The alone 150 miles and arrived at her destination surgeon reported that much disc material could have escaped among the nerve roots and into the with acute ankle pain and a mild foot drop on the spinal canal. right, the side of her accelerator-pedal foot. She By June, 5 months following surgery, his left low back and sciatic pain was largely relieved. habitually drove her car on long trips. On exami- The power of his foot dorsiflexion had returned to a large extent, although it was still weak. Much of nation, a clearly defined, triangular patch of cuta- neous hypesthesia was noted on the dorsum of the foot between the bases of the first and second toes. The sensory loss was more marked to cold than to touch. The upper part of the right peroneus longus
394 Part 3 / Leg, Ankle, and Foot Pain the impaired skin sensation had become normal, 5. Ibid. (Fig. 4 - 7 1 B ) . but the patient had constant pain in the leg and in 6. Ibid. (Fig. 4 - 7 1 C ) . the foot. This caused difficulty in sleeping at 7. Ibid. (Fig. 4 - 7 2 ) . night. He had been advised to exercise and he at- 8. Ibid. (Fig. 4 - 7 3 ) . tempted to jog. When he returned from jogging, he 9. Ibid. (Fig. 4 - 7 9 ) . could hardly move his left foot. At the end of the 10. Ibid. (Fig. 4 - 8 1 ) . day, he could not work. 1 1 . Ibid. (Fig. 4 - 1 0 6 ) . 12. Ibid. (Fig. 4-107). From this preliminary history, I suspected that he had a long second metatarsal bone. When he 13. Baker BA: The muscle trigger: evidence of came to see me, I did find the short first, long sec- overload injury. J Neurol Orthop Med Surg 7 : 3 5 - ond metatarsal Morton foot structure and a re- markably strong local twitch response in the left 44, 1986. peroneus longus muscle. Prickling in the foot was produced by pressing on the peroneal nerve just 14. Baker BA: Myofascial pain syndromes: ten sin- below the left fibular head over the point of poten- gle muscle cases. J Neurol Orthop Med Surg 10: tial entrapment by the peroneus longus muscle. Although he had the Morton foot structure in both 129-131, 1989. feet, it was only the left foot that hurt, and the disc 15. Bardeen CR: T h e musculature, Sect. 5. In Mor- had protruded on the left side. He had a lower limb-length inequality, with the left lower limb ris's Human Anatomy, edited by C M . Jackson, shorter. Ed. 6. Blakiston's Son & Co., Philadelphia, The history revealed further that, when he was a boy, his feet hurt. To his recollection, his feet 1921 (pp. 512, 515-516). had always hurt. I stretched and sprayed the pero- 16. Basmajian JV, Deluca CJ: Muscles Alive, Ed. 5. neal muscles, long toe extensors, and the tibialis anterior muscles bilaterally. Then, I placed first Williams & Wilkins, Baltimore, 1985 (pp. 334, metatarsal pads in his shoes and corrected the lower limb-length inequality with a heel lift on 335, 337, 345, 378-379). the left side. 17. Basmajian JV, Stecko G: The role of muscles in Following the treatment, the patient had his first night's sleep without pain for many months. arch support of the foot. An electromyographic He went jogging the next morning without any study. J Bone Joint Surg [Am] 4 5 : 1 1 8 4 - 1 1 9 0 , pain in either foot. The following day, I again stretched and sprayed the peroneal, anterior tib- 1963. ial, and toe extensor muscles. Three years later, this pain had not recurred. 18. Bates T, Grunwaldt E: Myofascial pain in childhood. J Pediatr 5 3 : 1 9 8 - 2 0 9 , 1 9 5 8 . In summary, the patient had a lower limb- length inequality with a shorter left lower limb 19. Bowker JH, Olin FH: Complete replacement of that caused greater impact of his weight on the symptomatic (left) side with left peroneal muscle the peroneus longus muscle by a ganglion with strain due to the mediolateral rocking foot of the Morton foot structure. Permanent relief required compression of the peroneal nerve: a case re- simply correction of the shoe for the Morton foot port. Clin Orthop 7 4 0 : 1 7 2 - 1 7 4 , 1 9 7 9 . structure, correction for lower limb-length ine- 2 0 . Broer MR, Houtz SJ: Patterns of Muscular Activity quality, and treatment by intermittent cold with in Selected Sports Skills. Charles C Thomas, stretch of the involved peroneal muscles and their associated extensor muscles in the leg. Springfield, 1967. 2 1 . Cachia W, Grumbine NA, Santoro JP, et al.: References Spontaneous rupture of the peroneus longus 1. Alexander IT, Johnson KA, Parr JW: Morton's tendon with fracture of the os peroneum. J Foot neuroma: a review of recent concepts. Orthope- Surg 2 7 : 3 2 8 - 3 3 3 , 1 9 8 8 . dics 1 0 : 1 0 3 - 1 0 6 , 1987. 2 2 . Carter BL, Morehead J, Wolpert S M , et al.: Cross-Sectional Anatomy. Appleton-Century- 2. Anderson A: Personal communication, 1991. 3. Anderson JE: Grant's Atlas of Anatomy, Ed. 8. Crofts, New York, 1977 (Sects. 72-85). 2 3 . Ibid. (Sects. 7 3 - 8 3 ) . Williams & Wilkins, Baltimore, 1983 (Fig. 4- 24. Ibid. (Sects. 8 0 - 8 4 ) . 70). 25. Clemente CD: Gray's Anatomy of the Human 4. Ibid. (Fig. 4 - 7 1 A ) . Body, American Ed. 30. Lea & Febiger, Phila- delphia, 1985 (p. 575). 2 6 . Ibid. (pp. 5 7 9 - 5 8 1 J . 27. Ibid. (p. 1 2 3 0 , Fig. 1 2 - 5 9 , pp. 1 2 4 1 - 1 2 4 3 ) . 28. Cox JS, Brand RL: Evaluation and treatment of lateral ankle sprains. Phys Sportsmed 5 : 5 1 - 5 5 , 1977. 2 9 . Cross MJ, Crichton KJ, Gordon H, et al.: Per- oneus brevis rupture in the absence of the per- oneus longus muscle and tendon in a classical ballet dancer: a case report. Am J Sports Med 16: 677-678, 1988. 30. Davies JA: Peroneal compartment syndrome secondary to rupture of the peroneus longus: a case report. J Bone Joint Surg [Am] 6 1 : 7 8 3 - 7 8 4 , 1979. 3 1 . Duchenne GB: Physiology of Motion, translated by E.B. Kaplan. J.B. Lippincott, Philadelphia, 1949 (pp. 305-9, 313, 319, 362-363, 395, 408). 32. Ibid. (pp. 3 4 5 - 3 4 6 ) . 3 3 . Evjenth O, Hamberg J: Muscle Stretching in Man- ual Therapy, A Clinical Manual. Alfta Rehab Ferlag, Alfta, Sweden, 1984 (pp. 140, 147).
Chapter 20 / Peroneal Muscles 395 34. Ferner H, Staubesand J: Sobotta Atlas of Human 63. Lenteil GL, Katzman LL, Walters MR: The rela- Anatomy, Ed. 10, Vol. 2. Urban & Schwarzen- tionship between muscle function and ankle berg, Baltimore, 1983 (Fig. 380). stability. J Sports Phys Therap 7 7 : 6 0 5 - 6 1 1 , 35. Ibid. (Fig. 4 5 8 ) . 36. Ibid. (Fig. 4 6 2 ) . 1990. 37. Ibid. (Figs. 4 6 5 , 4 6 7 ) . 64. Lockhart RD: Living Anatomy, Ed. 7. Faber & 38. Ibid. (Figs. 4 6 8 , 469). 39. Ibid. (Figs. 4 7 2 - 4 7 4 ) . Faber, London, 1974 (pp. 66-67, Figs. 136, 4 0 . Ibid. (Fig. 4 8 8 ) . 4 1 . Ibid. (Figs. 5 0 0 , 503). 138, 140). 4 2 . Ibid. (Fig. 504). 4 3 . Good MG: Painful feet. Practitioner 7 6 3 : 2 2 9 - 65. Lowdon IMR: Superficial peroneal nerve en- trapment. A case report. J Bone Joint Surg [Br] 232, 1949. 67:58-59, 1985. 44. Hammerschlag WA, Goldner JL: Chronic pero- 66. Mann RA, Moran GT, Dougherty SE: Compara- neal tendon subluxation produced by an tive electromyography of the lower extremity anomalous peroneus brevis: case report and in jogging, running, and sprinting. Am J Sports literature review. Foot Ankle 10A5-47, 1 9 8 9 . Med 7 4 : 5 0 1 - 5 1 0 , 1 9 8 6 . 45. Harris RI, Beath T: The short first metatarsal: 67. Matsusaka N: Control of the medial-lateral bal- its incidence and clinical significance. J Bone ance in walking. Acta Orthop Scand 5 7 : 5 5 5 - 5 5 9 , Joint Surg [Am] 3 1 : 5 5 3 - 5 6 5 , 1 9 4 9 . 1986. 46. Henstorf JE, Olson S: Compartment syndrome: 68. McAuliffe TB, Fiddian NJ, Browett JP: Entrap- pathophysiology, diagnosis, and treatment. Surg Rounds for Orthop: pp. 3 3 - 4 1 , Feb. 1987. ment neuropathy of the superficial peroneal nerve. A bilateral case. J Bone Joint Surg [Br] 67: 47. Jacobsen S: Myofascielt smertesyndrom (Myo- fascial pain syndrome). Ugeskr Laeger 7 4 9 : 6 0 0 - 62-63, 1985. 6 9 . M c M i n n RMH, Hutchings RT: Color Atlas of 601, 1987. 4 8 . Janda V: Muscle Function Testing. Butterworths, Human Anatomy. Year Book Medical Publishers, London, 1983 (pp. 200-202). Chicago, 1977 (pp. 282, 285, 289). 70. Ibid. (p. 305C). 49. Jeyaseelan N: Anatomical basis of compression 7 1 . Ibid. (p. 3 1 2 ) . of common peroneal nerve. Anat Anz 7 6 9 : 4 9 - 72. Ibid. (p. 3 1 8 ) . 73. Ibid. (p. 3 1 9 ) . 51, 1989. 74. Ibid. (p. 3 2 1 ) . 75. Morton DJ: The Human Foot. Its Evolution, Physiol- 50. Kamon E: Electromyographic kinesiology of jumping. Arch Phys Med Rehabil 5 2 : 1 5 2 - 1 5 7 , ogy and Functional Disorders. Columbia Univer- 1971. sity Press, New York, 1935. 76. Morton DJ: Foot disorders in women. J Am Med 51. Kellgren JH: Observations on referred pain arising from muscle. Clin Sci 3 : 1 7 5 - 1 9 0 , 1 9 3 8 Women's Assoc 7 0 : 4 1 - 4 6 , 1 9 5 5 . 77. Netter F H : The Ciba Collection of Medical Illus- (pp. 179, 186). 52. Kendall FP, McCreary EK: Muscles, Testing and trations, Vol. 8, M u s c u l o s k e l e t a l S y s t e m . Part Function, Ed. 3. Williams & Wilkins, Baltimore, I: Anatomy, Physiology and Metabolic Dis- 1983 (pp. 138, 143). orders. Ciba-Geigy Corporation, Summit, 53. Kernohan J, Levack B, Wilson JN: Entrapment 1987 (p. 98). of the superficial peroneal nerve. Three case 78. Ibid. (p. 99). reports. J Bone Joint Surg [Br] 6 7 : 6 0 - 6 1 , 1 9 8 5 . 79. Ibid. (pp. 1 0 0 , 104). 54. Kopell HP, Thompson WAL: Peripheral Entrap- 8 0 . Ibid. (p. 1 0 2 ) . ment Neuropathies. Robert E. Krieger Publishing 8 1 . Ibid. (p. 103). 8 2 . Ibid. (p. 107). Co., Huntington, New York, 1976 (pp. 34-38). 8 3 . Ibid. (pp. 1 0 9 , 1 1 1 ) . 55. Ibid. (pp. 4 0 - 4 3 ) . 56. Ibid. (pp. 4 4 - 5 0 ) . 84. Pagliano J: The final word on the most talked- about toe in running. Runner's World: pp. 6 8 - 57. Krammer EB, Lischka MF, Gruber H: Gross 69, Sept. 1980. anatomy and evolutionary significance of the human peroneus HI. Anat Embryol 7 5 5 : 2 9 1 - 3 0 2 , 85. Parashar SK, Lai HG, Krishnan NR: 'Harvesters 1979. Palsy': Common peroneal nerve entrapment 58. Lange M: Die Muskelharten (Myogelosen). J.F. neuropathy. (Report of 5 cases). J Assoc Physi- cians India 2 4 : 2 5 7 - 2 6 2 , 1 9 7 6 . Lehmanns, Munchen, 1931 (pp. 136, 137, Fig. 86. Peacock KC, Resnick EJ, Thoder JJ: Fracture 43). of the os peroneum with rupture of the per- 59. Larsen E: Longitudinal rupture of the peroneus brevis tendon. J Bone Joint Surg [Br] 6 9 : 3 4 0 - oneus longus tendon: a case report and re- view of the literature. Clin Orthop 2 0 2 : 2 2 3 - 341, 1987. 226, 1986. 60. Leach RE, Purnell MB, Saito A: Peroneal nerve 87. Perlmutter M, Ahronson Z, Heim M, et al.: A entrapment in runners. Am J Sports Med 17: case of foot-drop and the significance of a pop- 287-291, 1989. liteal mass. Orthop Rev 7 0 : 1 3 4 - 1 3 6 , 1 9 8 1 . 8 8 . R a s c h PJ, B u r k e R K : Kinesiology and Applied 61. LeMelle DP, Janis LR: Longitudinal rupture of Anatomy, Ed. 6. Lea & F e b i g e r , P h i l a d e l p h i a , the peroneal brevis tendon: a study of eight 1978 (pp. 318, 319-320, 330, Table 17-2). cases. J Foot Surg 2 8 : 1 3 2 - 1 3 6 , 1 9 8 9 . 89. Reynolds MD: Myofascial trigger point syn- 62. Le Minor JM: Comparative anatomy and signif- dromes in the practice of rheumatology. Arch Phys Med Rehabil 6 2 : 1 1 1 - 1 1 4 , 1 9 8 1 . icance of the sesamoid bone of the peroneus longus muscle (os peroneum). J Anat 7 5 7 : 8 5 - 99, 1987.
396 Part 3 / Leg, Ankle, and Foot Pain 90. Rohen JW, Yokochi C: Color Atlas of Anatomy, Ed. 2. 98. Takebe K, Hirohata K: Peroneal nerve palsy due to Igaku‐Shoin, New York, 1988 (p. 426). fabella. Arch Orthop Trauma Surg 99.91‐95, 1981. 91. Sammarco GJ, DiRaimondo CV: Chronic peroneus 99. Thompson FM, Patterson AH: Rupture of the peroneus brevis tendon lesions. Foot Ankle 9:163‐170, 1989. longus tendon: report of three cases. J Bone Joint Surg [Am] 71:293‐295, 1989. 92. Sidey JD: Weak ankles. A study of common peroneal entrapment neuropathy. Br Med J 3: 623‐626, 1969. 100. Travell J: Low back pain and the Dudley J. Morton foot (long second toe). Arch Phys Med Rehabil 56:566, 1975. 93. Simons DG: Myofascial pain syndrome due to trigger points, Chapter 45. In Rehabilitation Medicine edited 101. Travell J, Rinzler SH: The myofascial genesis of pain. by Joseph Goodgold. CV. Mosby Co., St. Louis, 1988 Postgrad Med 77:425‐434, 1952. (pp. 686‐723, see pp. 711‐712, Fig. 45‐9E). 102. Travell JG, Simons DG: Myofascial Pain and Dys- 94. Simons DG, Travell JG: Myofascial pain syndromes, function: The Trigger Point Manual. Williams & Chapter 25. In Textbook of Pain, edited by RD. Wall Wilkins, Baltimore, 1983. and R. Melzack, Ed 2. Churchill Livingstone, London, 1989 (pp. 368‐385, see p. 378, Fig. 25.9F). 103. Ibid. (pp. 86‐87). 104. Ibid. (p. 88). 95. Sridhara CR, Izzo KL: Terminal sensory branches of 105. Ibid. (p. 110‐112). the superficial peroneal nerve: an entrapment 106. Tropp H, Odenrick P: Postural control in single‐limb syndrome. Arch Phys Med Rehabil 66:789‐791, 1985. stance. J Orthop Res 6:833‐839, 1988. 96. Styf J: Entrapment of the superficial peroneal nerve. 107. Wilson RC, Moyles BG: Surgical treatment of the Diagnosis and results of decompression. J Bone Joint Surg [Br] 77:131‐135, 1989. symptomatic os peroneum. J Foot Surg 26: 156‐158, 1987. 97. Sutherland DH: An electromyographic study of the 108. Woltman HW: Crossing the legs as a factor in the plantar flexors of the ankle in normal walking on the production of peroneal palsy. JAMA 93: 670‐674, 1929. level. J Bone Joint Surg [Am] 48:66‐71, 1966.
CHAPTER 21 Gastrocnemius Muscle \"Calf Cramp Muscle\" HIGHLIGHTS: REFERRED PAIN from myofas- on the leg can activate the TrPs. Leaving the cial trigger points (TrPs) in the gastrocnemius foot plantar flexed for prolonged periods is likely muscle may extend from the instep of the ipsilat- to perpetuate them. PATIENT EXAMINATION eral foot, over the posteromedial aspect of the reveals primarily inability to extend the knee fully ankle and over the calf and back of the knee to with the ankle in dorsiflexion. TRIGGER POINT the lower posterior thigh. The most common EXAMINATION should include all four TrP loca- TrP, TrP1, located along the medial border of the tions in the gastrocnemius muscle. Proximally, medial head proximal to midbelly of the muscle, tender superficial aponeurotic bands along the projects the most extensive pattern. The other medial and lateral borders of the muscle can be three gastrocnemius TrP locations refer pain mistaken for tender taut bands of TrPs in the more locally around the TrP. ANATOMICAL AT- muscle fibers. ENTRAPMENT of nerves is TACHMENTS of this muscle cause it to span rarely caused by this muscle. However, some two joints, the knee and ankle. Proximally, the proximal configurations of its anomalous third medial and lateral heads attach separately to head can cause serious vascular compression the distal femur posteriorly; distally, the fibers that requires surgical release. ASSOCIATED end on an aponeurosis that joins the soleus TRIGGER POINTS are found in the agonistic muscle to form the tendo calcaneus. This com- soleus and hamstring muscles and sometimes bined tendon of the two muscles attaches to the in the long flexors of the toes and in the tibialis posterior surface of the calcaneus. A third head posterior muscle. TrPs in the gastrocnemius are of the gastrocnemius, when present, is an unu- also sometimes associated with TrPs in the an- sual variant that also attaches to the femur. IN- tagonistic tibialis anterior and long extensors of NERVATION of the gastrocnemius is supplied the toes. The INTERMITTENT COLD-WITH- by medial popliteal and tibial nerve fibers de- STRETCH procedure starts with the application rived from spinal segments S1, and S2. This mus- of ice or vapocoolant spray distalward over the cle FUNCTIONS to assist other plantar flexors in muscle and the referred pain pattern to the in- controlling the forward rotation of the leg over step. The patient is positioned prone to hold the the fixed foot during ambulation, and it contrib- knee straight while the ankle is passively dor- utes to stabilization of the knee. It acts in unusu- siflexed over the end of the treatment table to ally vigorous plantar flexion of the foot. The take up slack as muscle tension is released. IN- FUNCTIONAL UNIT that includes the soleus JECTION of TrP, and TrP2 is relatively simple muscle comprises a close-knit team. The chief and free of hazard. However, when injecting antagonists are the tibialis anterior and the ex- TrP3, an anomalous course of the popliteal ar- tensor digitorum longus. SYMPTOMS relating to tery can bring it within reach of the needle. The gastrocnemius TrPs are nocturnal calf cramps likelihood of such an aberrant course is greatly for TrP, and pain in the referred patterns evoked increased when a third head of the gastrocne- by any active TrPs in the muscle. ACTIVATION mius muscle is present. CORRECTIVE AC- AND PERPETUATION OF TRIGGER POINTS TIONS include reducing sustained plantar flex- in the gastrocnemius muscle depend largely on ion, e.g., by avoiding shoes with high heels and physical overload and malpositioning of the foot. by using a footrest if the heels do not reach the Climbing steep slopes, jogging uphill, riding a bi- floor when the individual is seated. Gastrocne- cycle with the seat too low, and wearing a cast mius self-stretch exercises are usually effective. 397
398 Part 3 / Leg, Ankle, and Foot Pain Immediate relief from calf cramps may be ob- trocnemius TrPs, which are perpetuated by sus- tained by passively stretching the gastrocne- tained plantar flexion of the foot at night. Also, mius muscle (dorsiflexing the foot, with the knee elevating the foot of the bed and taking vitamin straight). Recurrences of cramps are usually E as a therapeutic trial help alleviate nocturnal prevented by inactivating the responsible gas- calf cramps in some individuals. 1. REFERRED PAIN nemius TrPs associated with cramps. The (Fig. 21.1) nature of calf cramps and their relation to myofascial TrPs are considered further in Gastrocnemius TrPs tend to cluster in four Section 6. locations designated TrP1-TrP4 (Fig. 21.1). The first pair, TrP1 and TrP2, are found just The TrP1 referred pain pattern has been re- proximal to the midlevel of the medial and ported previously for adults,153, 155, 1 7 3 and a similar lateral muscle bellies, respectively. The pattern has been reported in children.23 other two, TrP3 and TrP4, are located be- hind the knee near where the medial and Good64 illustrated four locations of \"myalgic lateral heads each attach to a femoral con- spots\" in the gastrocnemius muscle that are simi- dyle. Thus, each head has two TrP regions, lar to our designated TrP sites. He identified this located toward its outer margin. The most muscle as the source of foot pain that was relieved common, TrP1, occurs distal to the knee, by injecting procaine into all of these myalgic close to the medial border of the medial spots. Sola156,157 illustrated pain from TrPs in the head of the gastrocnemius muscle (TrPi, medial and lateral margins of the gastrocnemius Fig. 21.1). This TrP1 refers pain primarily muscle as extending around the TrPs. Kelly83 de- to the instep of the ipsilateral foot with a scribed pain from \"fibrositic lesions\" in this mus- spillover zone that extends from the region cle as extending anywhere from the back of the of the lower posterior thigh, over the back knee to the lower part of the leg; the pain was re- of the knee, and down the posteromedial lieved by injecting the lesions with procaine. Ar- aspect of the leg to the ankle. cangeli and associates13 illustrated the pain from a \"trigger area\" located between the areas we de- The next most common location for scribe as TrP, and TrP2, which projected pain gastrocnemius TrPs is TrP2, which is along the back of the lower limb from above the found slightly more distal, near the lateral knee to midleg. border of the belly of the lateral head. This TrP2 and the two remaining gastrocne- Kellgren82 demonstrated experimentally the po- mius TrPs, TrP3 and TrP4, all refer pain tential of gastrocnemius nociceptors to refer pain primarily locally around and near the TrP by injecting 0.2 mL of 6% saline solution into the (Fig. 21.1). muscle belly. Pain radiated over the posterior as- pect of the lower limb from the buttock to the an- Tenderness in the region of TrP3 and kle. TrP4 can be caused by musculotendinous tension produced by taut bands accompa- The association of gastrocnemius TrPs with in- nying a TrP1 or TrP2. Either or both of the termittent claudication and the fact that claudica- two TrP regions behind the knee (TrP3 tion pain may be markedly increased by the TrPs and TrP4), however, may harbor TrPs are discussed in Section 6 of this chapter. with their own palpable taut bands in the absence of the two more distal TrPs. They 2. ANATOMICAL ATTACHMENTS AND produce pain primarily in the popliteal CONSIDERATIONS fossa. Rarely, all four gastrocnemius TrPs (Fig. 21.2) occur together. In that case, after the more distal TrP1 and TrP2 have been inacti- The gastrocnemius is the most superficial vated, the patient then becomes aware of muscle of the calf and is primarily re- the pain in the back of the knee that is sponsible for its contour. The muscle caused by TrP3 or TrP4. crosses the knee and the ankle and is di- vided into two clearly separated bellies, Both TrP1 and TrP2 are likely to be asso- the medial and lateral heads. The medial ciated with nocturnal calf cramps, but head is thicker and extends farther dis- rarely are the two most proximal gastroc- tally than the lateral head. Proximally,
Chapter 21 / Gastrocnemius Muscle 399 Figure 21.1. Pain (dark red) referred from trigger lesser extent TrP2 in the belly of the lateral head, are points (Xs) in the right gastrocnemius muscle (light likely to be present when the patient has painful noc- red). The essential pain pattern is solid red. Red stip- turnal calf cramps. The two more proximal trigger pling indicates the spillover extension of the essential points, TrP3 and TrP4, project pain higher to the back pattern. TrP1 in the belly of the medial head, and to a of the knee. each head attaches to the corresponding two femoral attachments cover the proxi- condyle of the femur2,53,103 by a strong, flat mal two-thirds of the posterior surface of tendon and to the underlying capsule of each head. The muscle fibers angle be- the knee joint. The thickest part of the tween this superficial aponeurosis and tendon lies close to the outer margin of the deep aponeurosis of the tendo calca- each head. Distally, both heads have a neus.18 common attachment to the tendo calca- neus (Achilles tendon),6 which is fixed to The details of this fiber arrangement18 the posterior surface of the calcaneus are important when palpating for taut (Fig. 21.2). bands in this muscle. The fiber arrange- ment is poorly shown in Figure 21.2 and The muscle belly is 15-18 cm (6-7 in) also in the drawings of many anatomy long, but individual fibers are only 5.0— texts. Some illustrations,7, 18, 104, 1 0 8 , 1 3 8 how- 6.5 cm (2-21/2 in) in length.179 The fibers ever, do show this diagonal fiber orienta- are angled diagonally between their su- tion well. In general, the most proximal perficial and deep aponeuroses. fibers of the two heads of the gastrocne- mius muscle are strongly angulated to The aponeurosis of the tendo calcaneus form a \" V \" shape. As one proceeds dis- extends along the under side of the mus- tally, the fibers gradually become aligned cle almost to the knee to provide attach- with the leg. The most central fibers of ment for these relatively short fibers. A both heads, however, continue to angu- thickening of this aponeurosis divides the late toward the intermuscular septum. two heads and serves as an intermuscular When palpating the proximal portion of septum for attachment of muscle fibers. the muscle, it is important to distinguish This aponeurosis has the shape of a \" T \" between tender diagonal taut bands of in cross section. The aponeuroses of the
400 Part 3 / Leg, Ankle, and Foot Pain Femur Gastrocnemius, Figure 21.2. Attachments of the right gastrocnemius muscle (red) seen from lateral head the rear. The distal (deep) aponeurosis of the gastrocnemius merges with the superficial soleus aponeurosis to form the Achilles tendon. Gastrocnemius, medial head Soleus and gastrocnemius tendon Achilles tendon Calcaneus muscle fibers and longitudinally oriented The other bursa, the calcaneal subtendinous tendons that also feel firm and \"ropy.\" A bursa,6, 55 is interposed between the Achilles ten- tendon may exhibit tenderness along the don and the calcaneus.36 line of attachment of the fibers to the apo- neurosis. A sesamoid (the fabella) in the proximal tendon of the lateral head appeared in 2 7 - 2 9 % of dissec- A third head of the gastrocnemius muscle is a tions. A sesamoid was found about half as often in variant that has been reported in approximately the tendon of the medial head. Only about one- 5.5% of Japanese people and in 2.9-3.4% of peo- third of these sesamoids were bony; the others ple of other nationalities.78 This head attaches were cartilaginous.74 proximally to the posterior surface of the femur between the attachments of the medial and lateral Khan and Khan85 counted the proportions of heads and sometimes considerably proximal to red, intermediate, and white fibers (those with ox- them. Distally, the third head may join either the idative, combined, and glycolytic metabolism, re- medial or lateral head of the muscle, more often spectively) in three autopsy samples from each of the medial head.78 Detailed drawings of this third ten gastrocnemius and ten soleus muscles. They head show that it may cross over part or all of the found marked variability among individuals. The neurovascular bundle containing the popliteal mean percentages of these three fiber types in the vessels and tibial nerve.61 gastrocnemius muscle were, respectively, 56%, 11%, and 33%. (As expected, the soleus muscles Two bursae are associated with the gastrocne- had an even greater proportion of red fibers.) mius muscle. Illustrations of the lateral gastrocne- mius bursa2,5,34,53 show that it lies between the ten- The average length of muscle fibers in the sin- don of the lateral head of the gastrocnemius mus- gle-joint soleus muscle was only 3.7 cm (l'/2 in) as cle and the posterior capsule of the knee joint, and compared with an average length of 5.8 cm (25/IB that it sometimes communicates with the joint.34 in) in the gastrocnemius muscle that crosses two functional joints.178 The myoneural junctions in the gastrocnemius muscle of a stillborn infant were found to form a
Chapter 21 / Gastrocnemius Muscle 401 horseshoe-shaped line approximately halfway be- and descending stairs, jumping, and bi- tween the outer margins of the muscle and the cycling. midline separation of its two heads.30 The differences in function between the Supplemental References gastrocnemius and soleus muscles derive from differences in fiber length, fiber Both heads of the gastrocnemius are illustrated type, and anatomical attachments. The from behind with clear detail of fiber direc- gastrocnemius is a functional two-joint tion,7,18,104,108,138 and with a less detailed over- muscle that is shortened by knee flexion view.57,161,167 The tibial nerve and popliteal artery but has improved leverage for ankle func- and vein are shown passing between the two tion in the extended position of the knee. heads as the heads diverge to form the popliteal However, the soleus crosses only the an- fossa.3,52,106,124 kle and is mechanically unaffected by knee angle. The lateral head is presented from a lateral view with clear delineation of tendon and fibers,105,140 The chief action of the gastrocnemius and with less structural detail.55, 10,7 1 5 9 muscle, when the foot is free to move, is to plantar flex the foot; it also tends to The medial head is viewed from the medial as- produce supination. Although both heads pect with clear resolution of the extent of the apo- attach to the femur above the knee joint, neurosis,139 and with less structural detail.54,107 this muscle exerts only a limited effect as This head can also be seen from the front,56, 160 and a flexor of the leg at the knee, particularly in cross section.28,58 with the knee extended. The location of this attachment serves the purposes of ad- 3. INNERVATION justing gastrocnemius muscle length and stabilizing the knee joint. Both heads of the gastrocnemius muscle are supplied by branches of the tibial Actions nerve. The nerve fibers are derived from spinal segments S1 and S .2 4 , 3 5 , 3 7 At the knee, the gastrocnemius muscle may assist flexion. At the ankle, the gastrocne- 4. FUNCTION mius and soleus muscles together, through the tendo calcaneus, are the prime plantar During standing and walking, the gastroc- flexors of the foot. The gastrocnemius mus- nemius frequently functions in what is cle is most effective as a plantar flexor when sometimes called a \"reverse pull\"; that is, the knee is extended; as the knee becomes it pulls on the proximal segment. This progressively more flexed, this muscle loses muscle functions through lengthening effectiveness and plantar flexion of the foot contractions much of the time in the is accomplished increasingly by the soleus weight-bearing position. muscle. During ambulation, the plantar flex- The gastrocnemius, when contracted in the ors (including the gastrocnemius) re- weight-bearing limb with the knee held in full strain (control) the forward rotation of extension, assists stabilization of the knee the tibia on the talus during stance joint.130 phase,165 contribute to knee stability, provide ankle stability, and conserve The gastrocnemius also supinates the foot. energy by minimizing vertical oscilla- Duchenne44 observed this supination when he tion of the center of mass of the body.166 stimulated either head of the muscle. His ex- Ordinarily, they do not propel the body planation of this movement was that the force forward,166 and the gastrocnemius gen- of plantar flexion is transmitted through the erally contributes little or no push-off calcaneus primarily to the cuboid, and the cu- even in running.99 boid transmits the force to only the fourth and fifth metatarsals. This mechanism is illustrated The gastrocnemius muscle is inactive by Anderson.8 Because the force is applied or minimally active during erect stand- only to the lateral side of the foot, supination ing unless balance is disturbed, and be- occurs during plantar flexion. comes more active when one is leaning forward. It functions as a reserve mus- Although the gastrocnemius is reported to cle for plantar flexion in activities such flex the leg at the knee,35, 1 3 0 Duchenne44 points as walking up steep grades, ascending out that stimulation of the muscle produces, at most, a very weak flexion. It is fortunate that
402 Part 3 / Leg, Ankle, and Foot Pain the action at the knee is weak with the knee the lateral head at lesser angles of knee flexion extended, because generally, this muscle is act- during extension effort was interpreted as spe- ing most forcefully (at the ankle) when the cifically countering the slight tendency of the knee needs to be stabilized, as in running and quadriceps femoris muscles to produce an ad- jumping. However, with the improved leverage duction-type moment of force at the knee of the gastrocnemius for knee flexion when the joint.10 leg is flexed 9 0 ° , t h e m u s c l e ' s effect on f l e x - ion at that joint apparently takes on a new The gastrocnemius and soleus muscles significance. have the least refined motor control of any of the muscles in the body. Instead of the usual The relative activities of the soleus and the motor unit innervation ratio of about 500 medial head of the gastrocnemius muscle muscle fibers per motor nerve axon present change markedly when a strong effort is re- in the majority of skeletal muscles, these two quired to both flex the knee and plantar flex muscles have nearly 2,000 muscle fibers per the ankle.65 With the knee fixed at 90° of flex- axon.20 ion and the ankle fixed in the neutral posi- tion, sitting subjects were asked to exert ef- Functions fort to produce various combinations of knee flexion and ankle plantar flexion at 0, 25%, Postural Control 50%, and 100% of maximum voluntary force. The gastrocnemius responded with increas- In the standing position, the gastrocnemius and ing electrical activity for all combinations of soleus muscles are activated to maintain balance effort. With increasing simultaneous effort at when the line of gravity is in front of the axis of both the knee and ankle joints, gastrocnemius the ankle joint. There is frequently a periodicity in activity increased markedly while that of the the activity of these muscles that is apparently re- soleus declined.65 This selective activation of lated to an almost imperceptible forward-and- the gastrocnemius apparently occurs because backward sway of the body. A shift of as little as of the greater flexion force the muscle can ex- 5° produces reflex activity of the posterior or ante- ert when the knee is bent than when it is rior leg muscles. The soleus tends to become ac- straight. It takes place despite shortening of tive before the gastrocnemius under light loads.21 the gastrocnemius muscle when the knee is flexed. Campbell and associates27 used fine-wire elec- trodes inserted into the medial and lateral heads The medial and lateral heads of the gas- of the gastrocnemius muscle proximally and into trocnemius muscle show some functional dif- the medial and lateral portions of the soleus mus- ferences. Andriacchi and co-workers,10 using cle distal to the gastrocnemius fibers to ensure fine-wire electrodes, tested four healthy clear separation of recorded EMG activity. They males who exerted isometric knee-flexion ef- found that when the subjects stood in bare feet the fort to resist a strong knee-extension force two heads of the gastrocnemius were quiescent ranging up to 32 newton-meters with the until contraction was needed to give impetus to knee held at an angle of 40° of flexion. Elec- forward motion. Inversion of the foot while stand- t r o m y o g r a p h i c (EMG) activity of t h e lateral ing barefoot increased activity at all four sites; head during knee flexion effort reached however, the activity in both the medial head of only 1 0 - 2 0 % of maximum EMG activity the gastrocnemius and the medial portion of the for all angles and all force levels tested. soleus increased threefold as compared to that in The force exerted ranged from 8-32 the lateral electrode sites. Eversion of the foot pro- newton-meters. The only vigorous re- duced an equal increase in activity in both heads sponse of the gastrocnemius muscle to of the gastrocnemius. The stabilizing function was k n e e f l e x i o n effort w a s b y t h e medial h e a d tested when standing on heels of various heights at 40° of flexion; its EMG activity reached and widths. Both heads of the gastrocnemius 70% of maximum at 32 newton-meters of showed increased stabilizing activity when con- force.10 fronted with unstable heel foundations. The considerable antagonistic activity of the In another study,21 standing on heels 6 and 7.5 medial head on knee extension effort was in- cm (21/2 and 3 in) in height increased the EMG ac- terpreted as supplying a stabilizing force for tivity observed in the lateral head of the gastroc- the knee joint.10 The vigorous graded activity of nemius muscle. Campbell and co-workers27 also observed that, in movements requiring variable effort, the ath-
Chapter 21 / Gastrocnemius Muscle 403 letes in their study showed smoothly graded in- restrains forward rotation of the tibia on the talus creases and decreases in muscle activity among as the weight is shifted during stance phase from the four sites in the gastrocnemius and soleus that the heel to the ball of the foot.165,168 were monitored. In non-athletes, there was no such smooth variation; both the degree and dura- The two heads of the gastrocnemius muscle, tion of activity fluctuated markedly and in no par- and the medial and lateral portions of the soleus ticular pattern. Apparently, either training or an muscle, when monitored with surface electrodes, athletic propensity imparted a synchronous showed a remarkably constant timing of the EMG blending of component muscular activities that activity pattern with regard to the phase of gait. was absent in non-athletes. There was a 75% increase in activity when the walking speed was increased from 2.5 to 4.2 mph When standing subjects were required to re- and the grade was increased from 0° to 10°. In con- spond to sudden forceful movements of their trast, the vasti medialis and lateralis of the quadri- hands and arms, EMG activity for stabilization ceps femoris showed a much greater response to consistently appeared in the gastrocnemius mus- these increases in load.24 The timing of EMG activ- cle before local responses appeared in the upper ity of the two heads of the gastrocnemius coin- extremity muscles.39 cided closely during normal level walking. How- ever, the highest percent of maximum-effort EMG Okada118 found that the postures that produced activity reached in 10 subjects was nearly 4 0 % for the most EMG activity in the medial and lateral the medial gastrocnemius and soleus muscles, but heads of the gastrocnemius muscle were standing only about 20% for the lateral gastrocnemius.49 on the balls of the feet and leaning forward while standing with the feet flat on the floor. Ninety de- Regardless of uphill grade or speed during walk- grees of forward flexion of the trunk induced less ing, calf muscle activity rapidly increased just activity. Standing straight produced negligible ac- before heel rise and reached its peak intensity at the tivity in either head of the gastrocnemius; when transition from knee extension to knee flexion as standing at ease, the muscle on the side bearing the ankle began to plantar flex.24 This study con- the most weight sometimes briefly reached 10% of firmed the earlier observation that EMG activity of maximum EMG activity.118 the gastrocnemius muscle predominates in the mid- dle part of the stance phase and its intensity is rela- Relating EMG activity to the center of foot pres- tively independent of speed. In addition, the opti- sure, Okada and Fujiwara119 used surface elec- mum pace period per gait cycle for minimum EMG trodes and found that all parts of the triceps surae activity was about 1 sec ± 0.2 sec.110 were active when the center of pressure was in front of the middle of the foot, as measured from The EMG activity of the gastrocnemius showed the heel to the tip of the great toe. As the center of a variety of patterns at self-selected walking pressure moved posterior to that midregion, the speeds. Shiavi and Griffin148 performed sophisti- tibialis anterior became active instead of the calf cated computer analysis on the records of 25 nor- muscles. The transition at this part of the foot sug- mal individuals to identify different patterns of gests that the functional axis of the human foot for EMG activity during 16 segments of the gait cycle. dorsi-plantar flexion while bearing body weight They found five common patterns and three unu- lies adjacent to the transverse-tarsal joint rather sual ones. All common patterns began shortly af- than within the talocrural joint. ter the beginning of stance phase and continued to, and for various periods into, swing phase. Of Perry and associates125 examined the issue of se- the recordings made at the highest speed of walk- lectivity of surface electrodes for specific muscles ing (1.6 m/sec), 5% showed a separate, additional and concluded that only 60% of the activity rec- burst of activity just before and at the onset of orded over the gastrocnemius was attributable to stance phase. that muscle, and a mere 36% of the EMG activity recorded by surface electrodes over the soleus Recordings from surface electrodes on the gas- muscle derived from it. Similar non-selectivity of trocnemius muscle showed that loads equal to surface electrodes was reported by others.119,127 10% and 15% of body weight that were carried in The relative advantages and disadvantages of sur- one hand while walking increased the duration of face versus inserted fine-wire electrodes were ex- EMG activity only on the ipsilateral side, but a amined in detail and summarized by Andersson load of 20% increased activity in this muscle bi- and associates.9 laterally.63 Walking Stair Climbing The triceps surae apparently does not contract to A surface electrode study of 25 normal subjects assist \"push-off\" in walking or running,99,186 but ascending and descending stairs168 demonstrated
404 Part 3 / Leg, Ankle, and Foot Pain that during stair ascension the medial head of the mius muscle was active in the latter half of the gastrocnemius muscle was active in most people power (down) stroke and activity continued into throughout all of the stance phase and for a part of the early return stroke. double limb support. During stair descent, the muscle in most subjects anticipated weight bear- Subsequently, Ericson and co-workers48 found ing and remained active through stance phase un- that when subjects were riding an ergometer cy- til double limb support. In another analysis of the cle, the medial head of the gastrocnemius exerted same study,169 the authors concluded that the its peak effort (19% of maximum EMG activity) in atypical patterns of gastrocnemius activity were the middle of the downward power stroke, but the not related to speed of climbing, and occurred for lateral gastrocnemius did not reach its peak effort no apparent reason. (23% of maximum EMG activity) until the begin- ning of the upward return stroke and maintained a Running, Jumping, and Sports high level for another 90° of pedal movement. A lesser initial peak of the lateral head was timed so Mann and co-workers99 monitored the EMG activ- that it could help move the opposite pedal for- ity of this lower limb muscle with surface elec- ward beyond dead center preparatory to the next trodes during jogging, running, and sprinting. In power stroke. The remaining activity during up- all these activities, the amount of plantar flexion ward pedal movement may relate to knee stabili- that occurred while the gastrocnemius muscle zation or flexion. The two heads apparently per- was active was a small percentage of the plantar formed different functions, but the nature of the flexion observed through the gait cycle. This is difference is conjectural. Activity of the soleus further indication that this calf muscle contributes muscle was synchronous with the downward little or nothing at push-off. Activity at this time power stroke and faded quickly on the return helps knee extension by preventing dorsiflexion stroke. Activity of the medial gastrocnemius mus- at the ankle. The consistent activity of the gastroc- cle was not affected by a change in foot position nemius prior to heel-strike, when the tibialis ante- on the pedal, which changes the mean ankle load rior is also active, probably contributes to stabili- moment of force twofold.48 Together, the plantar zation of the ankle joint.99 flexors of the foot contributed about 20% of the total muscular work on the ergometer cycle.47 Kamon,81 using surface electrodes on the lateral head of the gastrocnemius muscle, found that Resection of Muscles when the subject performed a standing jump, an abrupt burst of EMG activity appeared at take-off The effect of anatomical loss on strength and func- and stopped suddenly at the commencement of tion was studied in nine patients who had lost at air-borne flight. Moderate activity reappeared least one head, but not all, of the triceps surae.100 before landing and sometimes remained through- Only two patients reported a mild symptom: un- out the landing and stabilization period. steadiness of gait when walking on uneven ground. One had lost the lateral gastrocnemius Bilateral EMG activity of the lateral head of the and lateral soleus, and the other, all of the soleus gastrocnemius was monitored with surface elec- and the medial head of the gastrocnemius. Among trodes during the single-foot volleyball spike and these nine patients, in whom up to 75% of the tri- basketball layup. In both situations, EMG activity ceps surae muscle mass had been removed, the was vigorous and greater on the dominant side, loss of plantar flexion strength never exceeded but not as vigorous as that recorded with equal 30% with the foot in the neutral position, com- amplification from the medial section of the pared with the normal contralateral side. soleus muscle distal to the gastrocnemius fibers.26 In a study of one woman who was normal ex- The same recording arrangement26 was used to cept for surgical excision of the gastrocnemius record the EMG activity during 11 other right- and soleus, Murray and associates114 found that handed sports activities that included overhand the subject was able to compensate for most of her throws, underhand throws, tennis and golf gait abnormalities by excessive lateral tilt and pro- strokes, and hitting a baseball. In each of these, longed quadriceps femoris activity. Her disability the EMG activity of the soleus was more vigorous was mild and consisted of inability to increase than that of the lateral head of the gastrocnemius walking speeds beyond the normal pacing. muscle. In this right-handed subject, activity in the right gastrocnemius was always greater than As demonstrated earlier,72 the gastrocnemius activity in the left gastrocnemius. was more active when an effort was made to plan- tar flex the foot rapidly in the plantar flexed posi- Bicycling tion, and the soleus was more active when that same effort was exerted in the dorsiflexed posi- Houtz and associates76 found that, during station- ary bicycling, the medial head of the gastrocne-
Chapter 21 / Gastrocnemius Muscle 405 tion. This conclusion was reinforced100 by the ob- The contractile properties of the three parts of servation that the two patients in whom parts of the triceps surae in ten volunteers177 showed con- the gastrocnemius had been removed had greatest sistent differences when examined with surface loss of strength in plantar flexion, and those with- electrodes. The lateral head of the gastrocnemius out a soleus muscle suffered the greatest loss of had the fastest twitch, the medial head had strength with the foot in dorsiflexion. In those pa- slightly slower twitch, and the soleus muscle had tients in whom part of the gastrocnemius had the slowest twitch. The contraction times were, been removed, loss of strength was greatest on fast respectively, 100, 114, and 157 ms and the half- angular motion at the ankle. This observation sup- relaxation times were 101, 111, and 152 ms. This ports the view that the gastrocnemius is of greatest indicates that the medial head of the gastrocne- importance for the rapid development of power. mius functionally employed a slightly lower pro- portion of fast-twitch fibers than the lateral head Fiber Types, Contractile Properties, Blood Flow used, and that the soleus muscle had a much lower proportion of these fibers than did either The composition by fiber types of both heads of head of the gastrocnemius muscle. the gastrocnemius muscle and of the soleus was determined in 32 autopsies.46 The gastrocnemius To determine the nature of the shortening of muscle contained approximately 50% slow-twitch gastrocnemius muscles in stroke patients, Halar fibers (type 1) and the soleus muscle contained and associates66 compared the resting length and about 70% slow-twitch fibers. The two heads of extensibility of the muscle bellies and their ten- the gastrocnemius muscle showed no significant dons in stroke patients with those of normal con- difference in the proportion of fiber types. trols; resting length of the muscle belly was short- ened in stroke patients, but not that of its tendon. A study of 11 normal subjects of both sexes and The spastic muscle fibers appeared to have nor- of unknown athletic training89 compared the mal passive elongational characteristics; the cause smoothed rectified surface electromyograms of of the shortening was in the contractile tissue of the soleus and lateral gastrocnemius muscles di- the muscle, not in the tendon. rectly on an X-Y plot to identify the relative tim- ing and contribution of each muscle during slow Examining the force of contraction required to and fast contractions. As expected, the soleus interrupt blood flow in the triceps surae as deter- muscle, with predominantly slow-twitch (type 1) mined by clearance of 133Xe, Sadamoto and associ- fibers, initiated slow contractions. With rapid ates146 found that the mean values for force of con- contractions (hopping on one foot), the lateral traction that would stop intramuscular blood flow head of the gastrocnemius sometimes initiated the varied between 50% and 64% of the force of maxi- activity and sometimes did not. It apparently was mum voluntary contraction. Interestingly, with used occasionally as a supplementary muscle. increasing fatigue, the muscle \"softened\" and its contraction more readily obstructed blood flow. Clarkson and co-workers32 found that maximum As fatigue developed, the mean rectified electro- isometric strength was strongly related to fatiga- myogram increased and/or the force of contraction bility of the gastrocnemius muscle. They biopsied decreased, although the intramuscular pressure the medial gastrocnemius of eight endurance ath- increased, which further compromised blood letes (competitive long distance runners) and flow. Apparently because of the greater angulation eight power athletes (experienced weight lifters). of its fibers, the soleus muscle developed lower When the subjects lay prone with the knees levels of intramuscular pressure than the gastroc- straight, plantar flexion at the ankle fatigued five nemius muscle did at the same percentage of max- times faster in the relatively strong power-trained imum voluntary contraction. This study estab- group than in the weaker endurance-trained lishes a lower limit to the strength of contraction group. Both groups performed the same effort/rest that causes onset of ischemia in brief contractions, exercise schedule.32 The same authors,31 in a com- but does not answer the question of how much panion study, found an equally impressive, but contraction-induced ischemia can be tolerated for inverse relation between strength and percentage a prolonged period of continuous contraction. of slow-twitch fibers. The abundance of slow- twitch fibers varied from a minimum of 4 0 % in 5. FUNCTIONAL (MYOTATIC) UNIT the strongest (power-trained) athlete to a maxi- mum of 95% in the weakest (endurance-trained) The gastrocnemius and soleus muscles athlete. There was no overlap in the percentage form a close-knit team. They share the range of slow-twitch fibers in these two groups of same Achilles tendon that attaches to the athletes. calcaneus. Differences in function be-
406 Part 3 / Leg, Ankle, and Foot Pain tween the two muscles relate to knee flex- for TrPs will demonstrate the myofascial ion and are described in the preceding component. Electrodiagnostic testing for section. neuropathy and imaging of the lumbo- sacral spine helps identify a radiculop- At the knee, the gastrocnemius assists athy. The ankle jerk is not affected by the hamstrings in flexion, as do also the TrPs in the gastrocnemius (although it plantaris, gracilis, and sartorius mus- can be suppressed by strongly active TrPs c l e s 1 2 9 and the popliteus. At the ankle, the in the soleus). In the case of piriformis en- gastrocnemius and soleus muscles are the trapment of the sciatic nerve (Chapter 10), primary plantar flexors. There, they are imaging is normal but appropriate elec- assisted by the plantaris, peroneus longus trodiagnostic studies show nerve conduc- and brevis, flexor hallucis longus, flexor tion abnormality. digitorum longus, and tibialis posterior muscles.80,131 Pain in the lower limbs due to myofas- cial TrPs in children under 5 years of age Antagonists to the gastrocnemius at the often is passed off as \"growing pains.\"22,23 knee are the four parts of the quadriceps Martin-du-Pan101 found that growing femoris muscle; antagonists at the ankle pains of the legs in 56 of 60 children were are the extensors of the toes and the tibi- caused by \"gelo-myose\" of the proximal alis anterior muscle. insertion of the gastrocnemius muscle. The description of \"gelo-myose\" (my- 6. SYMPTOMS ogelosis to other authors151) was compati- ble with myofascial TrPs. This section first presents the symptoms to be expected in a patient with active Patients who have undergone a suc- myofascial TrPs in the gastrocnemius cessful laminectomy for lumbar radicu- muscle. The differential diagnosis fol- lopathy may continue to complain of re- lows. Finally, two associated conditions ferred pain that is misinterpreted as the are reviewed, nocturnal calf cramps and pain for which they had received the sur- intermittent claudication. gery. Residual TrPs in posterior muscles of the lower limb, including the gastroc- The patient with only latent TrPs in the nemius muscle,145 are likely to be causing medial head (sometimes in the lateral this postlaminectomy syndrome. Inacti- head) of the gastrocnemius muscle may vation of these TrPs often relieves them of complain chiefly of calf cramps. When the pain completely. the TrPs become active, the patient is aware of pain in the calf, and sometimes Unfortunately, some laminectomy pa- in the back of the knee or instep of the tients develop postoperative arachnoradi- foot, as described and illustrated in Sec- culitis.132 In many of these cases, a part of tion 1 of this chapter. the pain is caused by myofascial TrPs, some of which may be in the gastrocne- The patient may complain of pain in mius muscle. Inactivation of the TrPs is the back of the knee on effort, as when recommended as part of the management climbing up steep slopes, over rocks, or program for this condition.132 Like others, when walking along a slanted surface, we have found that a search for active such as a beach or the side of a domed TrPs is often rewarded in patients with street. Patients with gastrocnemius TrPs postlaminectomy pain. are rarely concerned about weakness or restricted range of motion. In contrast to the previously mentioned situations in which symptoms caused by Differential Diagnosis myofascial TrPs are ascribed to other causes, there is a group of conditions that The pain referred from gastrocnemius should be recognized and whose symp- TrPs can easily be mistakenly attributed toms should not be misinterpreted as to other conditions. The posterior knee, myofascial in origin. Some of these condi- calf, and plantar foot pain from these TrPs tions are: tennis leg, posterior compart- can be misinterpreted as an S1 radiculop- ment syndrome, phlebitis, popliteal syno- athy.134 However, it is not unusual to see vial (Baker's) cyst, Achilles tendinitis, the activation of gastrocnemius TrPs as a and retrocalcaneal bursitis. complication of this radiculopathy. In this situation, examination of the muscle
Chapter 21 / Gastrocnemius Muscle 407 \"Tennis leg\" is a partial tearing of the medial from the swollen area may be helpful diagnosti- belly of the gastrocnemius muscle, which is caused by suddenly resisting dorsiflexion of a foot cally and therapeutically. held in marked plantar flexion with the knee in full extension, often with a degree of supination of Achilles tendinitis25,33 and retrocalcaneal bursi- the foot.14,62 Serving at tennis is the archetype of such an activity. Immediately after hitting the tis25,74,123 are more likely to be confused with the ball, the back foot, which is supinated in strong plantar flexion, is brought forward as the knee is referred pain and tenderness from soleus than extended. The foot then takes the force of the full body weight and the gastrocnemius is subjected to from gastrocnemius TrPs, and are discussed in a vigorous lengthening contraction. Patients with \"tennis leg\" experience a sudden intense pain in Chapter 22 of this volume. the calf, as if kicked, followed by circumscribed tenderness and swelling of the medial aspect of Calf Cramps the midcalf. The most frequent symptom clearly asso- In some cases of this musculotendinous rupture ciated with TrPs in the gastrocnemius of the gastrocnemius, the location of swelling and muscle is nocturnal calf cramps. tenderness is sufficiently proximal to be confused with thrombophlebitis.102 A few days following Such cramps (systremma) are common. rupture, a hematoma becomes evident in the calf Estimates of occurrence range from 40% and discoloration extends toward the medial mal- among unselected patients in New York97 leolus.14 The symptoms are sometimes attributed to 49% of the men, 75% of the women, to rupture of the plantaris muscle, but careful ex- and 16% of healthy children in Ger- amination reveals sharply localized tenderness many.113 Among 121 college students, 115 and, frequently, a palpable defect in the medial (95%) had experienced spontaneous mus- belly of the gastrocnemius close to the distal end cle cramps at least once, and 18 of these of its muscle fibers.62,102 115 (16%) were awakened from sleep more often than twice per month by Failure to recognize rupture of the medial cramps, usually of the calf muscles.116 head of the gastrocnemius muscle can lead to a serious complication, posterior compartment Cramps often develop when the subject syndrome.11,122 This causes more diffuse pain and has been sitting or lying too long without tenderness. It is best diagnosed by intracompart- movement and with the foot held in plan- mental pressure measurements employing contin- tar flexion with the gastrocnemius short- uous infusion or a wick catheter. Treatment ened. Usually the affected individual is should be a prompt and thorough decompression awakened by intense pain in one calf after fasciotomy.71 several hours of sleep with the foot strongly plantar flexed. The gastrocne- Phlebitis can be distinguished from myofascial mius muscle feels hard due to its vigorous TrPs by the relatively constant pain regardless of sustained contraction. Many patients seek muscular activity and the diffuse warmth, red- relief by getting out of bed and standing ness, swelling, and tenderness of the foot and leg. or walking. Walking tends to stretch the Thrombophlebitis is confirmed by Doppler ultra- gastrocnemius, but also requires its active sound and venographic studies. contraction, and voluntary contraction in the fully shortened position is a reliable A popliteal synovial cyst (Baker's cyst) causes a way to reactivate the cramp. palpable swelling in the popliteal space that is best appreciated when the knee is extended,115 The most effective relief is obtained by and is confirmed by sonography. This may cause stretching the cramped muscle, either by knee pain that should be distinguishable from passively or actively dorsiflexing the foot. myofascial TrPs by the lack of muscular involve- If effective relief measures are not taken, ment. A ruptured Baker's cyst may produce severe the cramp may last for half an hour or pain and tenderness that simulates thrombophle- longer. The muscle may then be sore for a bitis, which can occur with (probably as a result day or two afterward. Other lower limb of) a ruptured cyst. The rupture of the Baker's cyst muscles, including the tibialis anterior is confirmed by an arthrogram that shows the pas- and intrinsic foot muscles, can be simi- sage of dye from the joint to the calf muscles; the larly affected, either separately or with venogram is negative.88128 Aspiration of cyst fluid the gastrocnemius. Recently, the topic of muscle cramps was reviewed by Eaton.45 Calf cramps are associated with, and may be induced by, many medical con- ditions including dehydration (as dur-
408 Part 3 / Leg, Ankle, and Foot Pain ing hemodialysis),93, 1 0 9 , 1 4 2 electrolyte calf cramps often result.170 Sometimes, disturbance and metabolic alkalosis TrPs in the lateral head cause calf cramps. (from persistent vomiting),182 low serum Elimination of the TrPs, when present, magnesium,163, 1 8 2 , 1 8 3 hypokalemia (from usually relieves the calf-cramp syndrome. diarrhea),73 hypocalcemia,182 hypopara- The fact that calf cramps are so com- thyroidism,182 heat stress with myo- monly associated with TrPs has not been globinuria,144 Parkinson's disease with widely recognized. dystonia, and, possibly, diabetes.97,137 They are not related to occlusive vascular Botb calf cramps and myofascial TrPs disease.97 Calf cramps in 64% of 50 cancer are provoked when the muscle is placed patients were not benign idiopathic oc- in the shortened position for a period of currences but were, often ominously, of time, especially when sleeping at night,164 neurological origin.163 Rish135 noted that and by forceful contraction in the short- 20-30% of 1500 patients with lumbar ened position.92 Calf cramps and TrPs are disc disease and radiculopathy com- prone to occur in fatigued (or chilled) plained of night cramps in the compart- muscles97 and are relieved by passive ment supplied by the compressed nerve stretch.92 root: L5 compression produced cramps of anterior compartment muscles; S1 com- Another type of cramp is painless and does not pression produced cramps of posterior seem to be related to myofascial TrPs. It occurs in compartment muscles. The complaint hand muscles as well as in lower limb muscles was likely to persist despite surgical de- and develops in response to voluntary contraction compression of the nerve root. Although of the muscle(s) involved. Although painless, it the author135 made no reference to exam- usually is temporarily disabling because it is so ining the muscles for TrPs, this observa- strong that the antagonist muscles cannot over- tion reinforces the previous conclusion power it. This cramp also can be relieved by that nerve compression can initiate TrPs steady passive stretch of the contracted muscle. in muscles supplied by that nerve. In Patients with this type of cramp and hypokalemia these patients, the TrPs could have per- may obtain relief by taking supplemental potas- sisted following surgery and then could sium. have become major contributors to the leg cramps. Certain drugs (phenothiazines, Treatment of Nocturnal Calf Cramps vincristine, lithium, cimetidine, and bumetanide) can cause cramps.109 The management of nocturnal calf cramps is reviewed at the end of Section 14 in Sleep studies for two or three consecu- this chapter. tive nights on seven people who com- plained of painful leg cramps revealed Etiology of Nocturnal Calf Cramps two individuals with nocturnal my- oclonus, one with obstructive sleep ap- Quinine and many of the other drugs recom- nea, and two who were awakened by mended for treatment of calf cramps reduce cell cramps but showed no sleep abnormality. membrane excitability. Quinine increases the re- The timing of the cramps had no relation fractory period of muscle and decreases excitabil- to the stage of sleep. Nocturnal leg cramps ity of the motor endplate region.141 Chloroquine, a were not related to electroencepha- similar drug, may have a similar action. Pheny- lographic changes during sleep and no toin reduces abnormally increased excitability of disturbances characteristic of sleep pa- cell membranes. Carbamazepine apparently de- thology were noted.147 creases nerve excitability, and procainamide pri- marily decreases muscle fiber membrane respon- Cramps in the calf have been associated siveness. This suggests that increased excitability with blockage of movement of the proxi- of the myoneural junction or the sarcolemma of mal tibiofibular joint.96 the muscle fibers is a major factor causing calf cramps. (Although the mechanism for the sus- Myofascial TrPs as a Cause of Nocturnal tained contracture of muscle fibers in the taut Calf Cramps band of a TrP is not yet established, it would not be surprising if electrical instability of the muscle When TrPs are present in the medial head fiber membrane were a significant contributory of the gastrocnemius muscle, intermittent factor. These considerations suggest further exper- imental studies to resolve questions concerning
Chapter 21 / Gastrocnemius Muscle 409 the pathophysiology of both TrPs and calf cramp and the amount of EMG activity recorded. cramps.) As others also found,19,38,59 voluntary contraction of the ipsilateral antagonist quieted the cramp. A different mechanism is suggested by the ef- fectiveness of drugs, such as theophylline and In persons with Schwartz-Jampel syndrome, procainamide, that tend to increase vascular per- voluntary contraction of an involved muscle in- fusion in the muscle. Hirsch73 remarked that the duces a cramp with complex repetitive discharges muscle pump in the legs \"sleeps\" at night, which attributed to ephaptic transmission.79 This mech- contributes to venous stasis and circulatory insuf- anism might account for the appearance of ficiency in the calf muscles. Simmons150 empha- polyphasic potentials during nocturnal cramps. sized the probable importance of ischemia in the Single-fiber electromyography162 should make it pain of calf cramps. possible to determine whether ephaptic transmis- sion among the muscle fibers makes a local contri- EMG recordings of calf cramps have been pub- bution to the cramps. lished.42,109,148 The cramps are characterized by high-voltage, high-frequency, irregular bursts of Basmajian19 observed that the cramp induced in motor unit action potentials.93 Norris and co- calf muscles produced very active electrically nor- workers116 conducted an extensive EMG study of mal motor units while the antagonist tibialis ante- five healthy volunteers and four patients who ex- rior was electrically silent. Immediately following perienced episodic muscle cramps. They studied recovery with a variety of treatment maneuvers, both induced and spontaneous cramps, primarily recruitment of both groups of muscles was nor- in the quadriceps femoris muscle, using surface, mal. It is his impression that there is a reflex inhi- concentric, or microtip electrodes in multiple lo- bition of the antagonist muscle (tibialis anterior in cations. Their detailed report makes a number of this case) and that an external mechanical assist valuable observations. No EMG or clinical differ- (passive stretch of cramping muscle) is required to ence existed between spontaneous cramps and overcome the inhibition. Thus, both the voluntary those induced by maximally contracting the mus- effort and external assistance to stretch the mus- cle in the shortened position (as also observed by cles that are cramping are essential components to Basmajian19). During cramping, some motor unit optimal treatment. The reason for this needs to be potentials were as much as twice the amplitude investigated. of, and were polyphasic as compared with, poten- tials previously recorded at the same site with the Relation to Myofascial Trigger Points same needle during a voluntary contraction. Dur- ing a cramp, the firing rate of individual motor Most of the clinical features of nocturnal units greatly increased, sometimes to double the calf cramps are compatible with their be- rate (from 34 to 60 discharges per second) ob- ing causally related to myofascial TrPs. served during voluntary contraction.116 The local twitch response (LTR) of TrPs is likely to have a close relation to calf The authors116 also observed that the more in- cramps; to our knowledge, this relation- tense the EMG activity recorded, the harder (more ship has not been explored experimen- tense) the muscle felt, and the more pain the sub- tally. TrPs are not the sole cause of ject experienced. When a muscle cramp was left cramps, however, and a full understand- alone, the involuntary electrical activity (and ing of nocturnal muscle cramps awaits pain) gradually subsided. This spontaneous reso- further research. lution could result from local metabolic depletion in the muscle or by neural \"fatigue\" at the spinal Intermittent Claudication level. The term intermittent claudication ap- The following observations from this study118 plies when an individual experiences calf suggest that central nervous system control, at pain after walking a fixed distance. It is least at the spinal level, plays a role in nocturnal generally assumed that the pain is either cramps. During a cramp, the electrical activity caused by exercising ischemic leg mus- was spotty throughout the muscle, unlike the cles or is of neurogenic origin caused by more uniform distribution of motor unit activity spinal stenosis. However, in many pa- during normal voluntary muscular contractions. tients, myofascial TrPs are a major con- The locations of electrical activity in the muscle tributor to the pain. The TrPs are appar- shifted from place to place during the cramp. Vol- ently induced, at least in part, by the im- untary contraction of the corresponding contralat- paired circulation. eral muscle increased the painfulness of the
410 Part 3 / Leg, Ankle, and Foot Pain Arcangeli and associates12 examined 27 patients scribed a patient who had cutaneous TrPs associ- with intermittent claudication for spot tenderness in the gastrocnemius, soleus, and anterior tibialis ated with intermittent claudication that restricted muscles. Using a pressure algometer, they found hyperalgesic areas in one or more of these muscles walking to 46 meters (50 yards). Three TrPs were in 12 (44%) of the patients. No diffuse tenderness located in the skin overlying the belly of the right of muscles was found. The pain threshold in these myalgic areas was below 800 gm; it was above calf muscle. Infiltrating them with anesthetic 1200 gm in the homologous region of the normal leg or, if that contralateral area had been ampu- caused excruciating pain down to the outer malle- tated, in the biceps femoris. In eight of the 27 pa- tients (30%), pressure on a tender spot induced re- olus, but afterward the patient could walk 366 me- ferred pain in a distribution that was similar to the pain patterns referred from TrPs in these mus- ters (400 yards) and resumed playing 18 holes of cles.173 Arcangeli et al.12 also found that muscles subject to claudication became painful following golf. injection of lower concentrations of sodium chlo- ride solution than did the uninvolved contralat- In summary, a major component re- eral muscles. The ischemic muscles were dif- sponsible for the pain of intermittent fusely more reactive to this noxious stimulus; this claudication in many patients may be may relate to their tendency to develop TrPs. myofascial TrPs in the gastrocnemius and soleus muscles. The TrPs appear to de- In a subsequent study of intermittent claudica- velop as a result of the ischemia. Inactiva- tion, Arcangeli and other co-workers13 found that tion of the TrPs improves performance the pain and other discomforts that occurred dur- because of pain relief, but does not im- ing walking were mainly localized in the calf prove circulation. (81% of 58 patients). Myalgic spots that referred pain on pressure were identified (as in the earlier 7. ACTIVATION AND PERPETUATION study) and were often located in the triceps surae OF TRIGGER POINTS and tibialis anterior muscles. In seven of these pa- tients, the walking distance was related more to Gastrocnemius TrPs are often activated by the sensitivity of myalgic spots than to the reduc- chilling of the muscle and by mechanical tion of calf blood flow. overload. Perpetuating factors include sustained contraction, sustained shorten- Travell and associates172 reported that seven of ing, immobility, and compromised circu- eight patients with advanced arteriosclerosis ob- lation. Some of these factors may contrib- literans and intermittent claudication, four of ute both to initial activation and to per- whom were also diabetic, experienced marked im- petuation of gastrocnemius TrPs. provement of their claudication pain by injection or spray and stretch of TrPs in their calf muscles. Activation of Trigger Points Improvement was measured by ergometer tests, walking tolerance, or toe-standing tests. Myofascial TrPs in the gastrocnemius muscle are likely to be activated by climb- Subsequently, Dorigo and associates43 studied ing up steep slopes and over rocks, by jog- TrPs in the calf muscles of 15 patients with inter- ging uphill, or by riding a bicycle with mittent claudication. They identified a TrP when the seat set too low. These situations re- digital pressure on a circumscribed tender spot in quire forceful plantar flexion at the ankle the muscle caused a jump response of the patient. with the knee bent. In some muscles, pressure on this spot also evoked referred pain. These TrPs were injected Another source of TrPs in the gastroc- with 10 mL of procaine solution. Any remaining nemius muscle is an accident that causes TrPs were similarly injected on subsequent visits, a fracture of the ankle or leg, which re- up to a total of 10 injections. Following this treat- quires the subject to wear a walking cast. ment, workload and work duration of the calf Myofascial TrPs may be initiated or acti- muscles increased significantly. However, the vated by muscular reaction to the same peak blood flow and duration of exercise hypere- stress that caused the fracture. A walking mia in the muscles did not change. cast fixes the ankle, and thus immobilizes and deconditions the gastrocnemius mus- TrPs can be present in the skin as well as in the cle, which promotes development of muscle of the calf. Trommer and Gellman176 de- TrPs. These TrPs often remain latent until the cast is removed and the patient starts loading the deconditioned, stiff muscle. The TrPs then become active and cause pain.
Chapter 21 / Gastrocnemius Muscle 411 Walking along a slanted surface, such to be troubled by this kind of superficial as a beach beside the ocean or the side of pressure. a domed street or road, can activate TrPs in the medial head of the gastrocnemius Walking straight up a long steep hill re- muscle on the lower side of the slant and peatedly can perpetuate gastrocnemius produce pain in the back of the knee with TrPs. Relief is obtained by zigzagging each step. This pain is likely to feel as if it back and forth, in effect reducing the arises in the knee joint. The patient tends steepness of the grade. to be tilted toward the low side so that limb becomes effectively shortened, re- As noted previously, any situation that quiring the gastrocnemius muscle and the markedly shortens the gastrocnemius pelvis to compensate. muscle for a prolonged period aggravates and perpetuates its TrPs. This shortening Standing in one position while leaning occurs when the knee is bent and the foot forward for a prolonged period places the is plantar flexed. Such situations include: gastrocnemius muscle under sustained wearing high heels, hooking the heel on tension and aggravates its TrPs, causing a the rung of a high stool with the foot cramplike pain. This can occur, for in- pointed down, driving long distances in a stance, when one must lean forward to car with an accelerator pedal that is an- reach a microphone at a lectern or to gled too nearly horizontal, and sleeping at work at a kitchen sink that has no toe night with the foot plantar flexed at the room. ankle. All of these stress factors are aggravated Any situation that impairs circulation by cooling of the muscle, which seems to in the gastrocnemius muscle encourages be more vulnerable to TrPs when it is myofascial TrPs. The effect of ischemia chilled. was covered in the preceding section. A chair seat with a high front edge can pro- Baker16 evaluated 100 patients for myofascial duce compression of the thighs. When mild, this compromises venous return TrP involvement in 24 muscles bilaterally follow- from the legs; when severe, it may reduce arterial flow. This effect can occur also ing each patient's first motor vehicle accident. No when the chair seat is pitched downward at the back, raising the knees, or when the TrPs were found in the lateral head of the gastroc- seat is too high for a person of short stat- ure (see Fig. 16.6); both situations tend to nemius muscle in any of these patients. He16 lift the feet off the floor. found that the medial head of the gastrocnemius Reclining chairs can also reduce blood flow in the calf muscles, particularly the muscle only occasionally developed TrPs. In 16 gastrocnemius, when the leg rest has a high edge at calf level and provides inad- broadside accidents with the impact on the equate heel support. This arrangement places the weight of the leg on the calf driver's side, four patients developed TrPs in the muscles. Some ottomans and some dental chairs cause this problem. medial head of the left gastrocnemius muscle. Viral infections are generally myotoxic, However, in 16 broadside accidents on the pas- sometimes severely so, and usually in- crease the irritability of myofascial senger's side, the medial head was unaffected. Im- TrPs.175 pacts from in front were four times more likely to Farrell and associates50 observed a myopathy in involve the medial head of the gastrocnemius on 24 children following influenza B infection as the either side of the body than impacts from be- respiratory symptoms waned. It preferentially in- hind.16 volved the gastrocnemius and soleus muscles, and Perpetuation of Trigger Points caused severe pain and difficulty in walking. Long socks with a tight elastic band at the These muscles were exquisitely tender to palpa- top, or garters that compress the leg just below the knee and produce a red line tion. The foot was held in plantar flexion; dor- with a skin indentation, can strongly per- petuate and aggravate TrPs in the gastroc- siflexion was painful and actively resisted. Biop- nemius and peroneus longus muscles. (The resultant impairment of circulation sies showed segmental necrosis of muscle fibers.50 is similar to that caused by a tight shoul- der strap compressing the upper trapezius muscle.) The soleus is generally too deep
412 Part 3 / Leg, Ankle, and Foot Pain Figure 21.3. Pincer palpation of the lateral head of the right gastrocnemius muscle where its trigger points are most commonly located. Patient is lying on the left side with a pillow between the knees and legs for comfort. 8. PATIENT EXAMINATION tight gastrocnemius muscle produces pain (Fig. 21.3) in the calf or back of the knee. There is no reliable clinical technique for The dorsalis pedis and posterior tibial detecting a moderate degree of gastrocne- arteries are palpated for amplitude of pul- mius weakness in the presence of compe- sation to uncover evidence of arterial dis- tent soleus function.80,84 ease or entrapment. Patients with gastrocnemius and soleus 9. TRIGGER POINT EXAMINATION muscle TrPs are likely to have a flat- (Figs. 21.3 and 21.4) footed, stiff-legged gait; they have diffi- culty walking fast and walking on uneven The gastrocnemius muscle can often be de- ground. lineated by inspection if the foot is plantar flexed and the muscle is contracted.51,98 The patient who has TrP shortening of a gastrocnemius muscle usually cannot In many patients, one can examine the fully extend that knee when standing if gastrocnemius muscle by pincer palpation, the heel is kept flat on the floor. if the subcutaneous tissues are sufficiently slack and the adipose layer is not too thick. The examiner should look for high heels on the patient's shoes and for the The patient may be examined while ei- indentation caused by a tight elastic band ther recumbent or kneeling on a chair seat. of the stocking around the leg below the When recumbent, the patient lies on the knee. Either one is likely to aggravate side that places the head of the gastrocne- TrPs in the gastrocnemius muscles. Vari- mius muscle to be examined uppermost. cose veins over the calf, which dilate The lateral head is smaller and usually eas- when the person stands, suggest compro- ier to grasp for pincer palpation (Fig. 21.3) mised venous circulation at or above that than is the medial head (Fig. 21.4B). The level. Dilatation of these veins may not be lateral head is grasped by inserting the evident when the patient is lying down. thumb between its lateral border and the fibula with the fingers in the midline TrPs in the gastrocnemius muscle do not groove between the two bellies of the gas- inhibit the Achilles tendon reflex. (How- trocnemius. Pincer palpation is more in- ever, strongly active TrPs in the soleus formative if the patient's foot is placed in a characteristically do inhibit this reflex.) neutral position or is slightly plantar The ankle jerks are conveniently tested flexed to slacken the muscle partially. If while the patient kneels as shown in Fig- the intervening tissues are too thick or ure 2 1 . 4 A 6 7 This tendon reflex is aug- tight for pincer palpation of the muscle, mented by any strong muscular contrac- then flat palpation (Fig. 21.4A) is per- tion, such as clenching the teeth or pulling formed by compressing the muscle against the clasped hands against each other. the underlying bone to identify taut bands that harbor TrPs. Flat palpation is best The addition of dorsiflexion of the foot done with any slack in the muscle taken to hip flexion with the knee straight up by gentle dorsiflexion of the foot. (LaSegue maneuver, see Fig. 16.7B) is usu- ally considered positive for sciatic nerve or The most common TrPs, TrP1 and TrP2 spinal nerve root irritation when it causes (Fig. 21.1), are found proximal to the mid- pain or cramping in the posterior thigh. A point of the bellies of the muscle along its medial (Fig. 21.4) or lateral (Fig. 21.3)
Chapter 21 / Gastrocnemius Muscle 413 Figure 21.4. Palpation of the medial head of the right gastrocnemius muscle for trigger points. A, examination using flat palpation while the patient kneels on a chair seat and holds onto the back of the chair. (This position can also be used to test the ankle reflexes.) The foot may need to be slightly dorsiflexed to place optimal tension on the muscle. B, pincer palpation of the medial head (grasping the muscle between the fingertips and thumb) with the patient recumbent, lying on the affected (right) side; the right knee should be flexed about 35° with the ankle in a neutral position that takes up the slack in the muscle without causing excessive tension. Either pincer or flat palpation may be used in both positions. borders. Frequently local twitch re- of the muscle belly. This location was just slightly sponses (LTRs) can be elicited from these distal to where we find TrP1 His sclerometric (tis- TrPs by snapping palpation. sue compliance) measurements91 of one of these palpable hardenings in the gastrocnemius muscle The proximal TrPs, TrP3 in the medial permitted only 16-18 mm of skin indentation head and TrP4 in the lateral head (Fig. compared with adjacent control muscle tissue that 21.1), may be palpated in the popliteal allowed 24 mm of indentation. space. Only flat palpation can be used to palpate these proximal TrPs. Here LTRs are Popelianskii and co-workers126 studied 12 patients rarely observed because of the greater with osteochondrosis, 11 of whom had involvement depth of these TrPs (but they often can be of the calf muscles. These patients also had variable felt when the needle penetrates the TrP findings of L5 and S1 radiculopathy. To illustrate during injection). typical muscular findings in the gastrocnemius mus- cle, they described a patient with a tense band and Proximally, the aponeurosis of the gas- painful thickening within the medial head of the trocnemius is superficial to the muscle fi- muscle. Vibration of this nodular trigger zone caused bers and has a ropy consistency along the pain referred to the inside surface of the thigh. medial and lateral margins of the mus- Stretch of the calf muscle sharply increased the cle.7,18,1o4,1o8,138 Tenderness of the mus- pain, while massage softened the nodule and de- culotendinous junctions along these mar- creased the pain. Electromyographic evidence of an gins should not be confused with tender- early stage of denervation was observed in three of ness of taut bands of muscle fibers. Often, the 12 cases. This EMG finding in the gastrocnemius tenderness in both is present. muscle was related to pathomorphologic changes in the biopsy of two patients and to clinical symptoms Lange90 illustrated the location of palpable my- of S1 root compression in a third patient who ogelosis in the medial head of the gastrocnemius muscle along its medial border near the midlevel
414 Part 3 / Leg, Ankle, and Foot Pain Figure 21.5. Stretch position and ice or vapocoolant spray pattern (thin arrows) for trigger points (Xs) in the right gastroc- nemius muscle. To take up slack in the muscle, gentle pressure in a cephalad direction is applied by the operator's knee against the patient's forefoot, as in- dicated by the thick arrow. The patient's knee should be kept straight. Starting above the knee, the intermittent cold covers the entire posterior aspect of the leg and ankle (including the medial and lateral sides) and also the sole of the foot. A small pad may be used to soften the edge of the examining table where the ankle hangs over it in the neutral po- sition. Active range of motion and appli- cation of a moist heating pad over the gastrocnemius follow intermittent cold with stretch. showed normal biopsy findings. No clear-cut rela- TrPs in the posterior portion of the glu- tionship emerged among the conditions observed in teus minimus muscle refer pain and ten- this study. derness to the upper calf region and are likely to cause satellite TrPs in the gas- 10. ENTRAPMENTS trocnemius. No nerve entrapment due to TrPs in the It is interesting to note that TrPs do not gastrocnemius muscle has been identi- seem to develop in the antagonist quadri- fied. ceps femoris in association with TrPs in the gastrocnemius. When the popliteal artery lies more medial than usual, it can be entrapped by the medial head of However, the tibialis anterior and long the gastrocnemius. This can cause intermittent extensors of the toes are antagonists that claudication.42,77 Symptoms are relieved by divid- may become involved as part of the func- ing the medial head of the muscle. Iwai and asso- tional unit. ciates78 reported three cases in which a third head of the gastrocnemius muscle (described in Section 12. INTERMITTENT COLD WITH 2 of this chapter) caused symptomatic entrapment STRETCH of the popliteal vein; the symptoms were relieved (Fig. 21.5) by partial resection of the third head. Before releasing the tight gastrocnemius 11. ASSOCIATED TRIGGER POINTS muscle, showing the patient the limited range of dorsiflexion helps him or her ap- The soleus and hamstring muscles are preciate later the results achieved by treat- likely to harbor active myofascial TrPs ment. when TrPs have developed in the gastroc- nemius muscle. Also, when the pain from The use of ice for applying intermittent medial gastrocnemius TrPs has been re- cold with stretch is explained on page 9 of lieved, the distribution of pain may shift this volume and the use of vapocoolant distally because of remaining active TrPs spray with stretch is detailed on pages 6 3 - in the long flexors of the toes or in the 74 of Volume l . 1 7 4 Techniques that aug- tibialis posterior muscle. ment relaxation and stretch are described on pages 10-11 and alternative treatment methods are reviewed on pages 9-11 of this volume.
Chapter 21 / Gastrocnemius Muscle 415 Figure 21.6. Injection of the more distal trigger injecting TrP2 in the lateral head with the patient lying on the uninvolved (left) side. The solid circle marks points (TrP, and TrP2) in the right gastrocnemius mus- the head of the fibula. cle. A, injecting TrP, in the medial head of the muscle with the patient lying on the involved (right) side. B, When treating patients with gastrocne- blanket to help restore heat lost by expo- mius TrPs, it is important to keep this sure of the skin to room air and to the in- muscle warm by applying a dry heating termittent cold. pad over the abdomen to warm tbe core of the body. This warmth induces reflex va- Muscular reflexes produced by TrPs sodilatation that progressively warms the can cross from one lower limb to the lower limbs from proximal to distal. Cov- other. Therefore, it is wise to release gas- ering the body and opposite limb with a trocnemius muscle tightness on both blanket helps to conserve body heat. sides of the body even if only one muscle has active TrPs. (This principle also ap- For intermittent cold with stretch of the plies to the hamstring and adductor mag- gastrocnemius muscle, the patient lies nus muscles.) prone with the feet extending off the end of the examining table so that the knee re- To include the gastrocnemius muscle mains straight as the operator applies when treating the hamstring muscles (see firm pressure to the ball of the foot to take Fig. 16.11), one applies the coolant dis- up slack while dorsiflexing the foot at the tally over the calf with the patient supine, ankle (Fig. 21.5). At the same time, paral- the hip flexed 90°, and the knee straight. lel sweeps of ice or vapocoolant spray are Then, the gastrocnemius is passively applied distalward starting just above the stretched by dorsiflexing the foot during knee to cover the entire muscle and the brief application of intermittent cold. referred pain zone. 13. INJECTION AND STRETCH Immediately following intermittent cold (Figs. 21.6 and 21.7) with stretch, the patient slowly performs, several times, full active plantar flexion A detailed description of the procedure for and dorsiflexion of the foot, keeping the TrP injection and stretch of any muscle ap- knee straight. Then the calf is wrapped in a pears in Volume 1, pages 7 4 - 8 6 . 1 7 4 For in- moist hot pack or wet-proof heating pad to jection, the physician should wear gloves. rewarm the skin and to relax the muscle fully. The patient's body is covered with a The gastrocnemius is very prone to postinjection soreness. The medial head
416 Part 3 / Leg, Ankle, and Foot Pain Figure 21.7 Injection of the more proximal trigger with the patient prone. The transverse solid line marks the popliteal crease. B, injecting TrP4 in the lateral points (TrP3 and TrP4) in the popliteal portion of the head with the patient in the semi-side-lying position. right gastrocnemius muscle. The solid circle locates the fibular head. A, injecting TrP3 in the medial head is more vulnerable to this than the lateral would prohibit the use of a probing injec- head, perhaps because the TrPs in the me- tion technique. The frequent presence of dial head are more tender and are usually multiple TrPs requires widespread prob- more numerous. The muscle may remain ing with the needle to ensure inactivation sore for as long as 5 or 6 days following of as many TrPs in the cluster as possible. TrP injection and, for the first day or two, the patient may experience marked dis- For injection of the more distal TrPs in comfort while walking or standing. For the belly of the lateral head of the gastroc- this reason, one should avoid injecting nemius muscle (TrP2), the patient lies on TrPs in both the right and left gastrocne- the side opposite the leg to be injected mius muscles at the same visit; doing so (Fig. 21.6B). Otherwise, the same tech- might immobilize the patient. nique is employed as for the medial head. It is especially important, prior to in- Injection of TrPs in the proximal pop- jecting TrPs in tbis muscle, to ensure that liteal portion of the medial head is per- the patient's tissues are well supplied formed with the patient lying prone with vitamin C. If there is doubt, a sup- (Fig. 21.7A), and injection of the popli- plement of 1,000 mg of time-release as- teal portion of the lateral head of this corbic acid twice daily for 2 days prior to muscle is performed with the patient ei- injection is recommended. Smokers are ther prone or lying partly on the oppo- particularly likely to have low tissue site side (Fig. 21.7B). One should aim reserves of vitamin C and to experience the needle away from the midline to marked postinjection soreness. avoid the neurovascular bundle that passes through the popliteal space. To inject the most common TrPs in the When injecting TrP3 in the popliteal medial head (TrP1 area, Fig. 21.6A), the portion of the medial head, the possibil- patient lies on the same side as the leg to ity of a displaced popliteal artery must be injected. After cleansing of the skin, be considered; the pulsating artery can the TrP within a taut band is fixed be- be located by palpation before injection tween the fingers by pincer or flat palpa- so that it can be avoided. A test that tion. The TrP is injected with 0.5% pro- may indicate an anomalous medial caine solution, usually employing a 37- course of the artery is to determine mm (l1/2-inch), 22-gauge needle. There are whether the pedal arterial pulses are re- no major neurovascular structures within duced by passive dorsiflexion of the or near this portion of the muscle that foot with the knee straight, which
Chapter 21 / Gastrocnemius Muscle 417 Table 21.1 the gastrocnemius. In addition, high heels Check List of Gastrocnemius Corrective Actions reduce the normal activity of the gastroc- nemius during walking.94 Every effort POSTURE should be made to discourage the wearing Avoid shoes with high heels of high heels, especially by patients with Avoid excessive resistance of accelerator pedal in myofascial problems in the back or lower car limbs. Avoid too flat an accelerator pedal in car Provide adequate foot support when seated If the automobile accelerator pedal is Avoid hooking heels on rung of high stool too flat and positions the foot nearly par- allel to the floor in plantar flexion, it ACTIVITIES maintains the calf muscles in the short- Avoid smooth leather shoe soles on slippery floor ened position. A wedge can be added to Avoid vigorous kick with toes pointed in crawl the pedal surface to position the ankle stroke more nearly at a right angle. During a long Keep calves and body warm trip, drivers should get out of the car and Avoid tight elastic at top of socks walk around at least every hour or take Avoid excessive uphill walking turns at the wheel. Cruise control is very Avoid walking on surfaces slanted sideways helpful on long trips. HOME THERAPY Individuals of short stature are likely to Sit in an appropriate rocking chair experience persistent plantar flexion of Do gastrocnemius/soleus pedal exercise the feet that causes calf-muscle TrPs Do gastrocnemius standing self-stretch when the seat is too high for the heels to Do Lewit postisometric self-stretch for reach the floor. This situation can be cor- gastrocnemius rected by a footrest that lifts the legs and thighs sufficiently to position the ankles CALF CRAMPS at nearly a right angle. A slanted footstool Inactivate gastrocnemius TrP1 is ideal; a flexible sand bag or bean bag Passively stretch cramping muscle can serve as a foot support that is readily Avoid prolonged plantar flexion of foot (in bed) adaptable to the most comfortable posi- Try vitamin E supplementation tion, even at the dining room table. would further tighten the muscle and When sitting on a high (bar- or kitchen- compress the artery. type) stool, one should avoid hooking the heels over the rung and allowing the feet Following TrP injection, a few parallel to hang down fully plantar flexed. The sweeps of intermittent cold are applied as feet should be pushed back far enough on the muscle is passively lengthened fully. the rung to balance them in a neutral po- Then the patient actively moves the foot sition. slowly through full plantar flexion and dorsiflexion; quick jerky movements Activities should be avoided. Finally, a moist heat- ing pad is applied to the calf. When working on a slippery tile or well- waxed floor, one should avoid hard, 14. CORRECTIVE ACTIONS smooth leather soles that provide poor (Figs. 21.8-21.11) traction and easily overload the calf mus- cles. Adding half-soles of rubber or other Table 21.1 provides a summary of the high-traction material solves this prob- main corrective actions considered in this lem. section. When swimming, a vigorous crawl kick Corrective Posture and Activities with the toes pointed backward should be avoided if calf TrPs are a problem; such a Posture kick overloads the calf muscles in the shortened position. Heels in excess of 7.5 cm (3 in) are likely to cause sore toes, gastrocnemius TrPs, The gastrocnemius muscle is readily knee problems, and backache. Heels less subject to excessive cooling that can ag- than 5 cm (2 in) in height can also shorten gravate its TrPs. When the patient works at a desk in a cool room, a heater that
garters that constrict circulation. The elastic top in socks can be loosened by pressing it with a hot iron. It is wise to buy socks that have elasticity distributed uniformly throughout their whole length and are snug enough to stay up without a tight elastic band at the top. This uni- formity of pressure supports rather than constricts the circulation. Figure 21.8. Pedal Exercise using dorsiflexion and Home Therapeutic Program (Fig. 21.8-21.10) plantar flexion to ensure the normal range of motion of the gastrocnemius muscle and to enhance the venous Patients with gastrocnemius (and soleus) pumping action of the soleus muscle. The knees are TrPs are strongly encouraged to sit in a extended with the patient either seated or supine. One suitable rocking chair and to rock when foot moves in a cycle (dotted lines) to full plantar flex- engaged in sedentary activity, such as ion, then to full dorsiflexion, with a slow rhythmic watching TV. The movement prevents movement, while the other foot rests. Then the cycle is prolonged immobility of the calf muscles repeated with the opposite foot. The exercise contin- and increases their blood flow. ues with cycles of activity alternating between the feet. The numbers indicate the sequence of movements. A more specific and more vigorous form (For seated version of this exercise, see Soleus Mus- of gastrocnemius isotonic movement is pro- cle, Fig. 22.13) A, right foot, full plantar flexion, full dor- vided by the Pedal Exercise illustrated in siflexion, and pause in midposition. B, left foot, exer- Figure 21.8. The patient, either sitting or ly- cise as in A. ing supine, moves one foot rhythmically from neutral to plantar flexion, to dorsiflex- warms the space underneath the desk pro- ion, to neutral, and then pauses. The same tects the muscle. In a number of patients, cycle is performed with the other foot, and frequent exposure to this cold work space tben repeated, alternating feet. This exer- proved to be a critical perpetuating factor, cise helps to maintain the full functional correction of which permitted lasting inac- range of motion of the gastrocnemius mus- tivation of gastrocnemius TrPs. cle and when used at night in bed, may prevent night cramps. The patient with gastrocnemius TrPs must avoid tight elastic in socks and tight An excellent way to prevent reactivation of TrPs in the gastrocnemius muscles fol- lowing treatment is to have the standing patient perform a passive stretching exer- cise for this muscle (Fig. 21.9). For the most effective stretch, the patient must keep the knee on that side extended, the heel on the floor, and the foot aligned straight forward (rear foot in Fig. 21.9A), not turned outward (Fig. 21.9B). A magazine or small book can be placed under the forefoot (Fig. 21.9C) to increase dorsiflexion of the foot and stretch of the muscle. Attempting to stretch both gastrocnemius muscles simultaneously by leaning against a wall can be hazardous if the feet slip and should be avoided (Fig. 21.9D). However, bilateral stretching can be done safely and effectively in the seated position (see Fig. 16.13B). A sports medicine study of intercollegi- ate athletes95 revealed that the plantar flexors of the foot were among the most neglected muscles in the athletes' stretch- ing routines. The authors comment on how unfortunate it is that soccer players do not stretch their plantar flexors be- cause, in this sport, players with gastroc-
Chapter 21 / Gastrocnemius Muscle 419 Figure 21.9. Standing passive self-stretch exercise foot at the ankle. B, less effective technique because for the right gastrocnemius muscle. The heel on the the right lower limb is laterally rotated. C, addition of a side of the muscle to be stretched must remain solidly lift under the right forefoot to provide additional stretch on the floor as the patient shifts the pelvis forward with by increasing dorsiflexion at the ankle. D, hazardous the knee straight, dorsiflexing the right foot. A, effec- bilateral self-stretch: the patient can readily lose con- tive position for stretch with the foot pointed straight trol of balance and c a u s e jerky overstretching of the forward; stretch is increased by bending the opposite gastrocnemius muscles, especially if the feet slip knee to lower the body, which further dorsiflexes the backward on the floor. nemius tightness are particularly liable to rically against resistance (Fig. 21.104); (b) injuries [and developing TrPs]. relax and take a deep breath; (c) then slowly let the breath out and at the same time, Patients can often inactivate their own gently passively dorsiflex the foot, taking gastrocnemius TrPs by applying Lewit's up all of the slack that develops while ex- postisometric relaxation technique96 as a haling (Fig. 21.106). Repeat the sequence self-stretch exercise (Fig. 21.10). Starting in until no further range of dorsiflexion is ob- the long sitting position, the patient uses a tained at the ankle. One can employ this towel to dorsiflex the foot passively while procedure regularly to maintain the full keeping the knee extended (Fig. 21.104). range of motion and prevent recurrences of The standard Lewit technique is applied: gastrocnemius TrPs. (a) gently contract the tight muscle isomet-
420 Part 3 / Leg, Ankle, and Foot Pain Figure 2 1 . 1 0 . S e a t e d self-stretch with postisometric relaxation of the right gas- trocnemius muscle. The knee must re- main straight. Arrows indicate the direc- tions of the forces applied. A, initial posi- tion for a 5-second, minimal-strength, gentle isometric contraction of the right gastrocnemius against resistance during slow deep inhalation. Contraction is fol- lowed by relaxation facilitated by slow full exhalation. B, as relaxation occurs, the foot is passively dorsiflexed by pull- ing slowly on the towel, with just enough force to take up the slack that has devel- oped. The cycle may be repeated three or four times, or until the full stretch- length of the muscle is achieved. Nocturnal Calf Cramps Fowler59,60 and Conchubhair38 empha- (Fig. 21.11) sized that active stretch of the calf mus- cles by contraction of their antagonist, the Several kinds of treatments have been tibialis anterior, had the advantage of in- recommended for calf cramps: inactiva- voking reciprocal inhibition to quiet the tion of myofascial TrPs in afflicted mus- calf muscle contractions more effectively. cles, stretching the calf muscles, position- One must be careful, however, not to ing of the feet, electrolyte replacement, impose a prolonged contraction on the vitamins, drugs that stabilize excitable fully shortened antagonist muscle, or it membranes, drugs that improve circula- may develop cramps of its own. Should tion in the muscles, and electrical stimu- this occur, those cramps are also re- lation. lieved by passively stretching the mus- cle. Many patients have learned to get Stretching of the Muscle up and walk to relieve an acute noctur- nal calf cramp. Passively stretching the Passively stretching the gastrocnemius afflicted muscle usually provides relief much faster than does walking. The muscle by standing with the knee ex- combination of reciprocal inhibition supplemented with passive stretch is tended and moving the hips forward to the most effective.19 slowly dorsiflex the ankle (see Fig. Sontag and Wanner158 were so success- 21.94) has repeatedly been reported to ful using stretching exercises in the treat- ment of leg cramps (and knee pains) terminate calf cramps in a minute or among more than 100 patients that they considered stiff, shortened muscles to be t w o . T r a v e l l suggested4 0 , 4 5 , 7 0 , 8 8 , 9 2 , 9 7 , 1 1 6 , 1 8 0111 that application of vapocoolant spray combined with passive stretch may be more effective than passive stretch alone.
Chapter 21 / Gastrocnemius Muscle 421 Warmth Sleeping under an electric blanket or warming the calves with a heating pad at night generally reduces TrP irritability and the tendency of the muscle to cramp. The heating pad may also be placed on the abdomen for reflex heating. For indi- viduals who prefer not to sleep under an electric blanket or pad, effective neutral warmth (conservation of body heat) can be provided by wrapping the legs in a wool blanket or large wool scarf. Positioning of the Feet Figure 21.11. Foot support in bed to prevent noctur- An effective way to prevent nocturnal calf cramps is simply to prevent the feet from nal calf cramps and to reduce trigger-point irritability of remaining in the plantar flexed position the gastrocnemius muscle. A, correct support under during sleep. Plantar flexion of the foot is the sheet, which maintains the feet in a neutral posi- increased by the weight of heavy bed- tion at the ankle. This correction is effective in both the covers (as suggested in Fig. 2 1 . 1 1 6 and supine and side-lying positions. B, incorrect position also as illustrated by Weiner and Wei- (red X) with lack of foot support. ner180). Simply lying on an electric warmer and using a lighter bedcover may the cause of the symptoms. The authors158 help.69 A firm pillow or blanket roll do not mention myofascial pain or TrPs, placed against the feet under the top sheet but their findings and treatment are con- provides a \"footrest\" that holds the foot sistent with what we find in patients with in the neutral position and elevates the recurrent calf cramps caused by intermit- covers to provide a space for the feet (Fig. tent aggravation of latent myofascial TrPs 21.114). Lying on the side makes it easier in the gastrocnemius. to maintain a neutral foot position during sleep. Side lying alone does not ensure re- Norris and associates116 used fine-wire lief unless the individual develops an electromyograms of the gastrocnemius awareness of foot position during arousal and quadriceps muscles in a study of five and consciously returns the foot angle to healthy volunteers and four patients who neutral whenever it strays into plantar complained of calf cramps. They induced flexion. If the patient insists on sleeping cramps by having the subject contract the prone, he or she can place a pillow under muscle in the shortened position and in- the lower legs or slide down on the bed activated the cramps by passively stretch- until the feet hang over its end in order to ing the cramped muscle. Voluntary acti- maintain a neutral position of the foot. It vation of the antagonist muscle also rap- usually takes many nights of persistent ef- idly reduced the intensity of the cramp fort to develop new sleeping habits; there- and its electrical activity. This response fore, the patient should not expect speedy was also observed electromyographically relief. Uninterrupted restful sleep is an by Schimrigk148 and by Basmajian.19 How- important part of therapy for patients ever, Schimrigk noted that the effective- with myofascial pain. ness of antagonist activation waned and disappeared with repetition. Elevating the foot of the bed with lifts under it also was effective in reducing nocturnal calf cramps.181 An elevation of 23 cm (9 in) was recommended by one author.136 This procedure was thought to improve circulation by reducing venous pooling, but it also may have reduced plantar flexion of the feet.
422 Part 3 / Leg, Ankle, and Foot Pain Electrolyte Replacement Vitamin B2 (riboflavin or lactoflavin) has been recommended87 for this com- Electrolyte imbalance can increase the plaint during pregnancy. excitability of muscle and nerve cell membranes. Low potassium or calcium Membrane-Stabilizing Drugs reserves are recognized as predisposing to chronicity of myofascial TrPs.152, 154, 171 The most common medical therapy for nocturnal calf cramps has been quinine An increased incidence of nocturnal leg cramps sulfate, 300 mg orally, at bedtime.97,143,182 is observed in pregnant women97 for reasons that A dose of only 60 mg of quinine was re- are not clear.69 Since quinine is contraindicated in ported to be just as effective as 300 pregnancy, supplemental calcium is often pre- mg.75 However, two studies found qui- scribed and has been reported to be effec- nine ineffective in the elderly,17,178 and tive.69,9,7121 Hammar and coinvestigators68 com- a recent controlled study also found it pared treatment with calcium to an ascorbic acid ineffective in younger people as well.45 placebo in a controlled double-blind trial of 60 In two studies, investigators found the pregnant patients with leg cramps. A good re- combination of quinine, 240 mg, and sponse was seen in 75% of those taking calcium aminophylline, 180 mg, more effective and in 77% of those taking ascorbic acid as a \"pla- than quinine alone.112,133 The amino- cebo.\" No differences in blood C a + + or Mg+ + phylline was thought to improve circu- levels were observed in patients with and without lation in the lower extremities. leg cramps, and no differences in these levels were observed in the calcium-treated patients Chloroquine often provided prolonged before and during treatment. The authors con- relief that lasted weeks after treatment.120 cluded that either the symptom of leg cramps in Procainamide HC1 was reported to be use- pregnancy responds unusually well to placebo, or ful.182 Phenytoin, diazepam, diphenhy- else vitamin C had an unexpected salutary effect dramine,143,182 and carbamazepine92 have on leg cramps. In a similar, earlier study of 129 also been tried. pregnant patients in Africa, Odendaal117 also found that 75% of calcium-treated patients and Circulatory Drugs 77% of the patients given ascorbic acid reported a good response. Papaverine HC1 provided significant re- lief to geriatric diabetic patients with calf Vitamins cramps in a double blind cross-over study.164 Several reports strongly recommend vita- min E, 300 international units daily, as an Electrical Stimulation effective treatment for leg cramps115 and one author considered it more effective Mills and co-workers109 confirmed elec- and safer than quinine,29 although no re- tromyographically the resolution of calf ports of controlled studies were found. cramps by treatment with transcutaneous nerve stimulation. The calf cramp was in- Our own experience is that supplemen- duced by voluntary plantar flexion in an tal oral vitamin E (400 I.U. daily) for a atypical patient who had resting EMG ac- maximum of 2 weeks may eliminate the tivity in the muscle and muscle hypertro- cramps. Any vitamin E taken in a multivi- phy. tamin preparation should be included in this total dose. Vitamin E is a fat-soluble Electrical stimulation of sensory nerves vitamin, is well stored in the body, and during stretching was reported to be help- should be discontinued when the calf ful in achieving stretch of muscles subject cramps disappear. The course of supple- to cramps.88 mentation may be repeated if the cramps recur. Some patients are remarkably re- References sponsive to this supplementation. With it, TrPs respond well to local therapy and 1. Aitchison WR: Nocturnal cramps. NZ Med J 2: the patient remains free of cramps and 137, 1974. TrPs. 2. Anderson JE: Grant's Atlas of Anatomy, Ed. 8. Williams & Wilkins, Baltimore, 1983 (Fig. 4- 50). 3. Ibid. (Figs. 4 - 5 1 , 4 - 5 3 ) . 4. Ibid. (Fig. 4 - 5 2 ) .
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Chapter 21 / Gastrocnemius Muscle 425 102. McClure JG: Gastrocnemius musculotendinous 125. Perry J, Easterday CS, Antonelli DJ: Surface rupture: a condition confused with thrombo- versus intramuscular electrodes for electromy- phlebitis. South Med J 7 7 : 1 1 4 3 - 1 1 4 5 , 1984. ography of superficial and deep muscles. Phys 103. McMinn RMH, Hutchings RT: Color Atlas of Ther 6 7 : 7 - 1 5 , 1 9 8 1 . Human Anatomy. Year Book Medical Publishers, 126. Popelianskii la Iu, Bogdanov EI, Khabirov FA: Chicago, 1977 (p. 277B). 104. Ibid. (p. 294B). [Algesic trigger zones of the gastrocnemius 105. Ibid. (p. 305C). 106. Ibid. (p. 306A). muscle in lumbar osteochondrosis] (clinico- 107. Ibid. (p. 312 A & 8 ) . 108. Ibid. (p. 313). pathomorphological and electromyographic analysis). Zh Nevropatol Psikhiatr 8 4 : 1 0 5 5 - 1 0 6 1 , 109. Mills KR, Newham DJ, Edwards RHT: Severe 1984. muscle cramps relieved by transcutaneous nerve stimulation: a case report. J Neurol 127. Portnoy H, Morin F: Electromyographic study Neurosurg Psychiatry 4 5 : 5 3 9 - 5 4 2 , 1982. of postural muscles in various positions and 110. Milner M, Basmajian JV, Quanbury AO: Multi- movements. Am J Physiol 7 8 6 : 1 2 2 - 1 2 6 , 1 9 5 6 . 128. Ramchandani P, Soulen RL, Fedullo LM, et al.: factorial analysis of walking by electromy- ography and computer. Am J Phys Med 5 0 : 2 3 5 - Deep vein thrombosis: significant limitations of noninvasive tests. Radiology 7 5 6 : 4 7 - 4 9 , 258, 1971. 111. Modell W, Travell J, Kraus H, et al.: Relief of 1985. 129. Rasch PJ, Burke RK: Kinesiology and Applied pain by ethyl chloride spray. NY State J Med 52: 1 5 5 0 - 1 5 5 8 , 1952 (see pp. 1556, 1557). Anatomy, Ed. 6. Lea & Febiger, Philadelphia, 112. Morl H, Dieterich HA: Nachtliche Waden- 1978 (p. 309). krampfe-Ursachen und Behandlung. Med Klin 130. Ibid. (pp. 3 1 8 - 3 1 9 ) . 131. Ibid. (p. 3 3 0 ) . 75:264-267, 1980. 132. Rask MR: Postoperative archnoradiculitis: re- 113. Mumenthaler M: Nachtliche Wadenkrampfe. Dtsch Med Wochenschr 7 0 5 : 4 6 7 - 4 6 8 , 1980. port of 24 patients and the conservative ther- apy therefore. J Neurol Orthop Surg 7 : 1 5 7 - 1 6 6 , 114. Murray MP, Guten GN, Sepic SB, et al.: Func- 1980. tion of the triceps surae during gait. Compen- satory mechanisms for unilateral loss. J Bone 133. Rawls WB: Management of nocturnal leg Joint Surg [Am] 6 0 : 4 7 3 - 4 7 6 , 1 9 7 8 . cramps. West J Med 7 : 1 5 2 - 1 5 7 , 1 9 6 6 . 115. Nakano KK: Entrapment neuropathies, Chapter 134. Reynolds MD: Myofascial trigger point syn- 111. In Textbook of Rheumatology, Vol. 2, edited dromes in the practice of rheumatology. Arch by W.N. Kelley, E.D. Harris, Jr., S. Ruddy, et al. Phys Med Rehabil 6 2 : 1 1 1 - 1 1 4 , 1 9 8 1 . W.B. Saunders, Philadelphia, 1981 (pp. 1 8 2 9 - 135. Rish BL: Nerve root compression and night 1846, see pp. 1841-1843). cramps. JAMA 2 5 4 : 3 6 1 , 1 9 8 5 . 116. Norris FH Jr, Gasteiger EL, Chatfield PO: An 136. Rivlin S: Nocturnal calf cramp. Lancet 7:203, electromyographic study of induced and spon- 1973. taneous muscle cramps. EEG Clin Neurophysiol 137. Roberts HJ: Spontaneous leg cramps and \"rest- 9.139-147, 1957. less legs\" due to diabetogenic (functional) hy- 117. Odendaal HJ: Kalsium vir die Behandeling van perinsulinism. J Fla Med Assoc 6 0 : 2 9 - 3 1 , 1 9 7 3 . Beenkrampe tydens Swangerskap. S Afr Med J 138. Rohen JW, Yokochi C: Color Atlas of Anatomy, 48:780-781, 1974. Ed. 2. Igaku-Shoin, New York, 1988 (pp. 420, 118. Okada M: An electromyographic estimation of 421). 139. Ibid. (p. 4 2 2 ) . the relative muscular load in different human 140. Ibid. (p. 4 2 3 ) . postures. J Hum Ergol 7 : 7 5 - 9 3 , 1972. 141. Rollo IM: Drugs used in the chemotherapy of 119. Okada M, Fujiwara K: Muscle activity around malaria, Chapter 4 5 . In The Pharmacological Ba- sis of Therapeutics, edited by Goodman and the ankle joint as correlated with the center of foot pressure in an upright stance. In Bi- Gilman, Ed. 6. MacMillan Publishing Co., Inc., omechanics VIIIA, edited by H. Matsui, K. New York, 1980 (pp. 1038-1060, see p. 1056). Kobayashi. Human Kinetics Publ., Champaign, 142. Rowland LP: Cramps, spasms and muscle stiff- IL, 1983 (pp. 209-216). ness. Rev Neurol (Paris) 7 4 7 : 2 6 1 - 2 7 3 , 1 9 8 5 . 120. Parrow A, Samuelsson S-M: Use of chloro- 143. Rowland LP: Diseases of muscle and neuro- quine phosphate—a new treatment for sponta- muscular junction, Section 16, Chapter 537. In neous leg cramps. Acta Med Scand 7 8 7 : 2 3 7 - Cecil Textbook of Medicine, edited by J.B. Wyn- 244, 1967. gaarden, L.H. Smith, Jr, Ed. 17. W. B. Saunders, Philadelphia, 1 9 8 5 (pp. 2 1 9 8 - 2 2 1 6 , see pp. 121. Patterson MA: Treatment of cramps. Letter to the Editor. J R Soc Med 75:988, 1982. 2215-2216). 122. Patton GW, Parker RJ: Rupture of the lateral 144. Rowland LP, Penn AS: Heat-related muscle cramps. Arch Intern Med 734:1133, 1 9 7 4 . head of the gastrocnemius muscle at the mus- 145. Rubin D: An approach to the management of culotendinous junction mimicking a compart- myofascial trigger point syndromes. Arch Phys ment syndrome. J Foot Surg 2 8 : 4 3 3 - 4 3 7 , 1989. Med Rehabil 6 2 : 1 0 7 - 1 1 0 , 1 9 8 1 . 123. Pavlov H, Heneghan MA, Hersh A, et al.: The 146. Sadamoto T, Bonde-Petersen F, Suzuki Y: Haglund syndrome: initial and differential di- agnosis. Radiology 7 4 4 : 8 3 - 8 8 , 1 9 8 2 . Skeletal muscle tension, flow, pressure, and 124. Pernkopf E: Atlas of Topographical and Applied Human Anatomy, Vol. 2. W.B. Saunders, Phila- EMG during sustained isometric contractions in humans. Eur J Appl Physiol 5 1 : 3 9 5 - 4 0 8 , 1 9 8 3 . delphia, 1964 (Fig. 352). 147. Saskin P, Whelton C, Moldofsky H, et al.: Sleep and nocturnal leg cramps (letter). Sleep 11: 307-308, 1988.
426 Part 3 / Leg, Ankle, and Foot Pain 148. Schimrigk K: Muskelkater und Muskelkrampf. 166. Sutherland DH, Cooper L, Daniel D: The role of Med Welt 3 0 : 7 8 0 - 7 8 8 , 1 9 7 9 . the ankle plantar flexors in normal walking. J Bone Joint Surg [Am] 6 2 : 3 5 4 - 3 6 3 , 1980. 149. Shiavi R, Griffin P: Changes in electromy- 167. Toldt C: An Atlas of Human Anatomy, translated ographic gait patterns of calf muscles with walking speed. IEEE Trans Biomed Eng 30:73- by M.E. Paul, Ed. 2, Vol. 1. Macmillan, New 76, 1983. York, 1919 (p. 368). 150. Simmons VP: Muscle spasm—why does it 168. Townsend MA, Lainhart SP, Shiavi R: Varia- hurt? Philadelphia Med 7 8 : 3 0 7 - 3 0 8 , 1982. bility and biomechanics of synergy patterns of 151. Simons DG: Muscle pain syndromes—Parts I and II. Am J Phys Med 5 4 : 2 8 9 - 3 1 1 , 1 9 7 5 , and some lower-limb muscles during ascending and descending stairs and level walking. Med 55:15-42, 1976. Biol Eng Comput 7 6 : 6 8 1 - 6 8 8 , 1978. 152. Simons DG: Myofascial pain syndrome due to 169. Townsend MA, Shiavi R, Lainhart SP, et al.: trigger points, Chapter 4 5 . In Rehabilitation Med- icine, edited by Joseph Goodgold. C. V. Mosby Variability in synergy patterns of leg muscles Co., St. Louis, 1988 (pp. 686-723, see pp. 691, during climbing, descending and level walking 719). 1 5 3 . Ibid. (p. 712, Fig. 4 5 - 9 B ) . of highly-trained athletes and normal males. Electromyogr Clin Neurophysiol 7 8 : 6 9 - 8 0 , 1978. 154. Simons DG: Myofascial Pain Syndromes. In Current Therapy of Pain, edited by K.M. Foley, 170. Travell J: Symposium on mechanism and man- agement of pain syndromes. Proc Rudolf R.M. Payne. B.C. Decker Inc., Philadelphia, Virchow Med Soc 7 6 : 1 2 6 - 1 3 6 , 1957. 1989 (pp. 2 5 1 - 2 6 6 , see Table 4). 171. Travell J: Myofascial trigger points: clinical 155. Simons DG, Travell JG: Myofascial pain syn- view. In Advances in Pain Research and Therapy, dromes, Chapter 25. In Textbook of Pain, edited edited by J.J, Bonica and D. Albe-Fessard, Vol. by P.D. Wall and R. Melzack, Ed 2. Churchill Livingstone, London, 1 9 8 9 (pp. 3 6 8 - 3 8 5 , see 1. Raven Press, New York, 1976 (pp. 919-926). p. 378). 172. Travell J, Baker SJ, Hirsch BB, et al.: Myofascial component of intermittent claudication. Fed 156. Sola AE: Treatment of myofascial pain syn- Proc 7 7.164, 1952. dromes. In Recent Advances in the Management of Pain, edited by Costantino Benedetti, C. 173. Travell J, Rinzler SH: The myofascial genesis of pain. Postgrad Med 7 7 : 4 2 5 - 4 3 4 , 1952. Richard Chapman, Guido Moricca. Raven Press, New York, 1 9 8 4 , Series title: Advances in 174. Travell JG, Simons DG: Myofascial Pain and Dys- Pain Research and Therapy, Vol. 7 (pp. 4 6 7 - 4 8 5 , function: The Trigger Point Manual. Williams & see pp. 4 8 0 - 4 8 1 ) . Wilkins, Baltimore, 1983. 157. Sola AE: Trigger point therapy, Chapter 47. In 175. Ibid. (pp. 1 5 1 - 1 5 2 ) . Clinical Procedures in Emergency Medicine, ed- 176. Trommer PR, Gellman MB: Trigger point syn- ited by J.R. Roberts and J.R. Hedges. W.B. drome. Rheumatism 8 : 6 7 - 7 2 , 1952. Saunders, Philadelphia, 1985 (pp. 683-685). 177. Vandervoort AA, McComas AJ: A comparison 158. Sontag SJ, Wanner JN: The cause of leg cramps of the contractile properties of the human gas- trocnemius and soleus muscles. Eur J Appl and knee pains: an hypothesis and effective Physiol 5 7 : 4 3 5 - 4 4 0 , 1 9 8 3 . treatment. Med Hypotheses 2 5 : 3 5 - 4 l , 1988. 1 5 9 . Spalteholz W: Handatlas der Anatomie des Men- 178. Warburton A, Royston JP, O'Neill CJ, et al.: A schen, Ed. 11, Vol. 2. S. Hirzel, Leipzig, 1922 quinine a day keeps the leg cramps away? Br J Clin Pharmacol 2 3 : 4 5 9 - 4 6 5 , 1987. (p. 363). 1 6 0 . Ibid. (p. 3 6 4 ) . 179. Weber EF: Ueber die Langenverhaltnisse der 1 6 1 . Ibid. (p. 3 6 6 ) . 162. Stalberg E, Trontelj JV: Single Fibre Electromy- Fleischfasern der Muskeln in Allgemeinen. Berichte Ciber die Verhandlungen der Kdniglich ography. Miravalle Press Ltd., Surrey, 1 9 7 9 (pp. Sachsischen Gesellschaft der Wissenschaften zu Leipzig 3 : 6 3 - 8 6 , 1851. 99-107). 180. Weiner IH, Weiner HL: Nocturnal leg muscle 163. Steiner I, Siegal T: Muscle cramps in cancer cramps. JAMA 2 4 4 : 2 3 3 2 - 2 3 3 3 , 1980. patients. Cancer 6 3 : 5 7 4 - 5 7 7 , 1 9 8 9 . 181. Weller M: Nocturnal calf cramp. Lancet 7:203, 164. Stern FH: Leg cramps in geriatric diabetics 1973. with peripheral vascular ischemia: Treatment. J Am Geriatr Soc 1 4 : 6 0 9 - 6 1 6 , 1 9 6 6 . 182. Whiteley AM: Cramps, stiffness and restless legs. Practitioner 2 2 6 : 1 0 8 5 - 1 0 8 7 , 1 9 8 2 . 165. Sutherland DH: An electromyographic study of 183. Zumkley H: Nachtliche Wadenkrampfe. Dtsch the plantar flexors of the ankle in normal walk- Med Wochenschr 704:1128, 1 9 7 9 . ing on the level. J Bone Joint Surg [Am] 4 8 : 6 6 - 71, 1966.
CHAPTER 22 Soleus Muscle and Plantaris Muscle \"Jogger's Heel\" HIGHLIGHTS: REFERRED PAIN and tender- person walks at an easy pace, the soleus to- ness from myofascial trigger points (TrPs) in the gether with the gastrocnemius stabilizes (pre- distal portion of the soleus muscle usually ap- vents further flexion of) the knee through its ac- pear primarily in the posterior aspect and plantar tion at the ankle. The soleus becomes of critical surface of the heel and often include the distal importance during running and jumping. Be- end of the Achilles tendon. Pain may also pro- cause of large venous sinuses, a tough fascial ject to an area over the sacroiliac joint on the covering, and competent veins above, it is an ef- same side of the body. The TrPs in the proximal fective musculovenous pump that serves as a portion of the soleus usually refer pain and ten- \"second heart.\" Both the soleus and plantaris derness over the back of the calf. The plantaris muscles plantar flex and assist inversion of the muscle refers pain and tenderness primarily to foot. The plantaris weakly assists the gastrocne- the back of the knee; pain may extend down the mius muscle in flexion of the knee. The FUNC- back of the calf to the middle of the leg. ANA- TIONAL UNIT consists primarily of the soleus TOMICAL ATTACHMENTS of the soleus mus- and the gastrocnemius muscles, which are as- cle proximally are to the posterior surface of the sisted chiefly by the long flexors of the toes and head of the fibula and along the middle third of the posterior tibial muscle; chief antagonists are this bone's posterior border, to the middle third the tibialis anterior and the long extensors of the of the medial border of the tibia, and to the tendi- toes. SYMPTOMS caused by soleus TrPs are nous arch that spans the two bones. Distally, the primarily referred heel pain and tenderness, and soleus and gastrocnemius muscles join to form restricted dorsiflexion at the ankle. Pain and ten- the Achilles tendon. The soleus portion of the derness may be so severe that walking is diffi- tendon attaches to the medial one-third of the cult or impossible, especially walking uphill or up calcaneus. An accessory soleus sometimes ap- and down stairs. Soleus TrPs are one cause of pears as an additional belly of the soleus mus- growing pains in children. An accessory soleus cle; this accessory soleus is found anterior to muscle is readily mistaken for a soft-tissue tu- the Achilles tendon just above the ankle, usually mor. A rupture of the plantaris tendon should be chiefly on the medial side of the ankle. The distinguished from a tear of the gastrocnemius soleus muscle has short fibers that are predomi- or soleus muscle. Soleus TrPs are easily mis- nantly slow-twitch type 1. The frail, variable diagnosed as Achilles tendinitis, thrombophlebi- plantaris muscle attaches proximally to the fe- tis, or a popliteal (Baker's) cyst. A discussion of mur deep and medial to the lateral head of the the relation of shin splints to soleus TrPs com- gastrocnemius; it has a long tendon that passes pletes this section, and an extensive review of between the soleus and gastrocnemius muscles postexercise muscle soreness appears in the to attach to the medial side of the posterior part Appendix of this volume. ACTIVATION AND of the calcaneus. The FUNCTION of the soleus PERPETUATION OF TRIGGER POINTS are during gait is to contribute to knee stability, pro- caused by overload of the soleus when the indi- vide ankle stability, and restrain the forward ro- vidual walks in shoes with smooth leather soles tation of the tibia over the fixed foot. When a on a slippery surface, or walks on soft sand, 427
428 Part 3 / Leg, Ankle, and Foot Pain or on a laterally slanted surface, such as a niques, such as contract-relax, are even more beach. Jogging and running are also often re- effective when augmented with sychronized res- sponsible, as is the sudden overload from slip- piration (Lewit's postisometric relaxation) or with ping or almost falling. Leaving the muscle in the simultaneous antagonist contraction during the shortened position for prolonged periods, during stretch phase. These techniques can be effec- the day by foot positioning, during sitting, by tively incorporated in the application of intermit- wearing high heels, and at night by improper tent cold with stretch. This procedure should al- foot positioning in bed, strongly perpetuates ways be followed promptly by moist heat applied soleus TrPs. Circulation impairment by a leg rest over the muscle and then by active full range of can be an important contributing factor. Sys- motion. INJECTION of soleus TrPs is performed temic perpetuating factors must also be consid- with the patient side lying. Care is exercised to ered. PATIENT EXAMINATION when soleus avoid the tibial nerve, posterior tibial artery, and TrPs are suspected includes testing for restric- posterior tibial veins on those unusual occasions tion of dorsiflexion at the ankle with the knee when TrPs need to be injected deep in the mid- bent. The ankle jerk in response to an Achilles line of the muscle. Postinjection soreness of the tendon tap may be reduced in amplitude. A tap soleus muscle is often severe and can be re- with the percussion hammer on the belly of the duced by having the patient apply moist heat to muscle over the TrP may then induce a local the muscle twice daily and avoid strenuous ac- twitch response that appears similar to, but is tivity for a few days. CORRECTIVE ACTIONS NOT, a tendon tap response. TRIGGER POINT include modification of posture and activities of EXAMINATION of soleus TrPs can be con- daily living that overload the soleus muscle or ducted with the patient kneeling on a chair seat maintain it in a fixed, shortened position for pro- or side lying with the knee bent. The distal longed periods. Such modifications include soleus TrPs on the inner side of the Achilles ten- maintaining the feet in the neutral position by pil- don may be overlooked if pincer palpation does lows at night, by reducing excessive height of a not include both sides of the Achilles tendon in chair seat or by adding a footrest, and by not the grasp. The proximal TrPs require flat palpa- wearing high heels. Slippery soles of shoes are tion against the underlying bone. ENTRAP- corrected with a rubber half-sole. Leg rests MENTS of the blood vessels and tibial nerve at should support both heels and calf. Walking in the soleus canal can be aggravated, if not soft sand and on slanted surfaces should be caused, by TrPs in the proximal portion of the avoided by patients with soleus TrPs, and lower soleus muscle. An anomalous fibrous band of limb-length inequality should be corrected. Pa- the soleus muscle, when present, is another tients are taught how to angle the body and feet possible source of entrapment. The plantaris when going up and down stairs, and how to pick tendon can entrap the popliteal artery. INTER- things up from the floor without overstretching a MITTENT COLD WITH STRETCH of the soleus sore, tense soleus muscle and without exces- may be accomplished with the patient kneeling sive forward bending. Following treatment by on a chair seat or lying prone with the knee TrP injection, or by intermittent cold with stretch, flexed 90°. Sweeps of vapocoolant spray or ice the patient is given a home self-stretch program are applied distalward over the calf, heel, and in- to maintain and improve on the gains made. The step, and should also include the sacroiliac joint Soleus Pedal Exercise is useful for preventing area when that is painful. Simple stretch tech- recurrence of TrPs. 1. REFERRED PAIN pain.149 Spillover pain may be reported in the region of the trigger point (TrP) and (Figs. 22.1 and 22.2) sometimes slightly forward from the heel in the instep. This soleus TrP1 is generally Soleus located 2 or 3 cm distal to the end of the gastrocnemius muscle belly and slightly (Figs. 22.1 and 22.2) medial to the midline. The most common soleus trigger point, The less common and more proximal TrP1, (Fig. 22.1) refers pain and tender- TrP2 (Fig. 22.1) is found high on the lateral ness primarily to the posterior aspect and side of the calf. This soleus TrP causes dif- plantar surface of the heel and also to the fuse pain in the upper half of the calf. distal end of the Achilles tendon.136,150 Many runners complain of this heel
Chapter 22 / Soleus and Plantaris Muscles 429 Figure 2 2 . 1 . Pain patterns (dark red) referred from trigger points (Xs) com- monly observed in the right soleus mus- cle (light red). The essential pain pattern (solid red) denotes the pain experienced by nearly everyone in whom these trig- ger points are active. Red stippling indi- cates the occasional spillover pain pat- tern. The most distal trigger point, TrP1, causes heel pain and tenderness. The most proximal trigger point, TrP2, is as- sociated with calf pain (but not with noc- turnal calf cramps). An intermediate and less common trigger point, TrP3, slightly proximal and lateral to TrP1, refers pain mainly to the region of the ipsilateral sa- croiliac joint. The very rare soleus TrP3 (Fig. 22.1) is sees such totally unexpected patterns of slightly more proximal and more lateral pain referred from TrPs in other muscles, than TrP1 and refers deep pain in the ipsi- which emphasizes the importance of ob- lateral sacroiliac joint in an area about 2.5 taining a detailed and comprehensive cm (1 in) in diameter.135 Less frequently, pain history. this TrP3 may cause less intense spillover pain in the region of the TrP itself and Other authors reported that TrPs in the over the posterior and plantar surfaces of soleus muscle cause heel pain9 or pain in the heel, mimicking the pattern of TrP1. the heel and sole of the foot.7 An exceptional pain pattern referred to The TrPs in the soleus muscle do not the jaw from the TrP3 region has been ob- cause calf cramps, as do TrPs in the gas- served twice (Fig. 22.2). In one patient, trocnemius muscle. this TrP referred severe pain to the ipsi- lateral face deep in the jaws and temporo- Plantaris mandibular joint with malocclusion (Fig. 22.3) (\"Now my teeth don't meet,\" she said) whenever the ankle on that side was ac- Trigger points in the plantaris muscle tively or passively dorsiflexed, but with (Fig. 22.3) refer pain behind the knee and no pain that is usually characteristic of downward over the calf as far as the the soleus muscle. The jaw pain and midleg level. In some patients, a TrP in spasm were eliminated immediately by the vicinity of the plantaris refers pain to injecting soleus TrP3. Occasionally, one the ball of the foot and base of the big toe. However, it is not clear whether this pain arises from TrPs in the plantaris muscle
430 Part 3 / Leg, Ankle, and Foot Pain Figure 22.2. Exceptional pain pattern (red) referred Figure 22.3. Pain pattern (bright red) referred from a to the left face and jaw from a rare trigger point (X) in trigger point (X) in the right plantaris muscle (dark the ipsilateral (left) soleus muscle. red). The pain pattern back of the knee and usually extending down to midcalf locates the superficial dif- or in the fibers of the lateral head of the fuse pain experienced when this trigger point is active. gastrocnemius. of the tibia, and to the tendinous arch 2. ANATOMICAL ATTACHMENTS AND (Figs. 22.5 and 22.6) between the proxi- CONSIDERATIONS mal tibia and fibula. This arch forms the (Figs. 22.4-22.7) roof of the soleus canal. The canal en- closes the posterior tibial artery, veins, Soleus and tibial nerve. It is unusual that a tendi- (Figs. 22.4-22.7) nous arch for nerve and vessels should serve as a major attachment site for a The soleus muscle crosses only the ankle muscle. Distally, the soleus fibers attach joint region and not the knee joint, unlike to the underside of the aponeurosis that the gastrocnemius. The soleus acts across also provides an anchor for the gastrocne- the talocrural ('ankle') and the talocal- mius muscle. This aponeurosis forms the caneal (subtalar) joints. tendo calcaneus (Achilles tendon) that at- taches to the posterior part of the calca- The soleus muscle attaches proximally neus. to the posterior surface of the head of the fibula and along the proximal third of the The soleus muscle is enclosed between posterior surface of that bone (Fig. 22.4), two layers of unyielding fascia: the apo- to the middle third of the medial border neurosis of the Achilles tendon superfi- cially and a layer of tough fascia deep to the soleus, which is distinct from the thinner fascia that covers the deep poste-
Chapter 22 / Soleus and Plantaris Muscles 431 Gastrocnemius, Femur medial head (cut) Gastrocnemius, Plantaris lateral head (cut) Head of fibula Soleus canal Soleus Plantaris tendon Gastrocnemius tendon (cut and reflected) Tibia Fibula Achilles tendon Calcaneus Figure 22.4. Attachments of the soleus (dark red) gastrocnemius muscle (not colored) has been cut and and plantaris (light red) muscles of the right leg. The most of the muscle removed. rior compartment muscles. These thick and was drawn from a photograph of layers of fascia on the front and back of one of several cadaver dissections that the soleus muscle fuse together beyond showed this structure. When present, it the medial edge of the muscle to form an may contribute to entrapment of the impressively tough attachment to the me- neurovascular bundle at the proximal dial border of the tibia.96 In this way, the edge where the bundle enters the soleus soleus muscle and its fascia form an un- canal. yielding \"soleus bridge\" over the deep compartment, a fact that is important in The view showing the deep surface of the understanding and management of the soleus muscle (Fig. 22.6) depicts its deep posterior compartment syndromes attachment to the tendinous arch of the of the leg.96 This unusually rigid encase- soleus canal and also shows the neuro- ment of the soleus muscle may also help vascular bundle leaving the canal.29 to explain some of its unique hemody- namic characteristics. This same view illustrates the complex- ity of the soleus muscle. The most super- The fibular side of the soleus muscle ficial fibers overlap like shingles angling sometimes has a fibrous band (Fig. 22.5) down and outward. The deepest, more extending across the soleus canal to the proximal fibers have a bipennate arrange- medial condyle of the tibia. This band ment (Fig. 22.6). These fibers originate is not usually shown in anatomy texts. proximally from the tibia and fibula and It was observed by the senior author attach distally to a tendinous septum that is part of the Achilles tendon.
432 Part 3 / Leg, Ankle, and Foot Pain Tibial nerve Popliteal vein Popliteal artery Plantaris (cut end) Gastrocnemius Popliteus Fibula (cut ends) Entrance to soleus arch Tibia Soleus (cut) Fibrous band of soleus Peroneal artery and vein Popliteal veins Popliteal artery Tibialis posterior Flexor hallucis longus Posterior tibial artery Posterior tibial vein Tibial nerve Flexor digitorum longus Tibia Fibula Talus Flexor digitorum longus tendon Flexor hallucis Tibialis posterior tendon longus tendon Flexor retinaculum Plantaris tendon (cut) Achilles tendon, cut (attachment of soleus and Calcaneus gastrocnemius tendons) Figure 22.5. Superficial view of the soleus canal muscles (light red). The fibrous band that extends up- with the major portion of the right soleus muscle (dark ward from the medial side of the arch that forms the red) cut and removed. This shows the relations of the soleus canal is drawn from a photograph of an ana- soleus tendinous arch and the muscle to the posterior tomical specimen in which the band was unusually tibial artery (bright red), posterior tibial veins (black well developed. cross hatching), tibial nerve (white), and neighboring The fibers of the Achilles tendon Anatomical variations in the soleus muscle in- twist approximately 90°. The tendinous clude doubling (two layers),10,160 partial defi- fibers from the soleus attach to the me- ciency,160 or absence of the medial head.10 dial one-third of the calcaneus (Fig. 22.7)96 and the fibers from the gastroc- Accessory Soleus nemius attach to the lateral two-thirds of the bone. Occasionally, an accessory soleus muscle is identified. It appears as an additional belly of Figure 19.3 in Chapter 19 of this vol- the soleus muscle that extends distally from ume presents a cross-sectional view of the the deep surface of the soleus to the calca- soleus muscle at the level of the lower neus10 and usually lies more on the medial portion of the middle third of the leg, than on the lateral side of the tendon. The bulk well below the soleus canal.
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