Netter Concise Orthopaedic Anatomy 2nd Edition

5 Forearm • TOPOGRAPHIC ANATOMY Anterior view Posterior view Cephalic vein Median cubital vein Basilic vein Brachioradialis muscle Flexor carpi Flexor/pronator radialis tendon Thenar mass eminence Palmaris Brachioradialis 1 longus and extensor tendon carpi radialis longus muscles Flexor digitorum Mobile wad superficialis tendons 2 Flexor carpi Extensor carpi Olecranon of ulna 3 45 ulnaris tendon radialis brevis Radial head muscle Flexor carpi ulnaris muscle Extensor carpi ulnaris muscle Anatomic snuffbox Extensor pollicis longus tendon Extensor indicis 1 Cephalic vein tendon Lister’s tubercle Ulnar styloid 2 Extensor digitorum tendons 3 45 STRUCTURE CLINICAL APPLICATION Olecranon Proximal tip of ulna. Tenderness can indicate fracture. Radial head Proximal end of radius. Tenderness can indicate fracture. Flexor radialis tendon Landmark for volar approach to wrist. Radial pulse is just radial to tendon. Lister’s tubercle Tubercle on dorsal radius. “Lighthouse of the wrist.” EPL tendon runs around it. Ulnar styloid Prominent distal end of ulna. Tenderness can indicate fracture. Palmaris longus tendon Not present in all people. Can be used for tendon grafts. Anatomic snuffbox Site of scaphoid. Tenderness can indicate a scaphoid fracture. 140 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Right radius and ulna in Olecranon OSTEOLOGY • Forearm 5 supination: anterior view Trochlear notch Coronoid process Right radius and ulna in Head Radial notch of ulna pronation: anterior view Neck Ulnar tuberosity Oblique cord Radial tuberosity Ulnar tuberosity Oblique cord Ulna Radius Ulna Radius Lateral surface Anterior surface Anterior surface Posterior border Posterior surface Anterior border Anterior border Interosseous border Dorsal (Lister’s) tubercle Interosseous membrane Groove for extensor Interosseous Interosseous border carpi radialis longus membrane and brevis muscles Groove for extensor pollicis longus muscle Area for extensor pollicis brevis and abductor pollicis Groove for extensor longus muscles digitorum and extensor Styloid process indicis muscles Styloid process Ulnar (sigmoid) notch Styloid process of ulna Radius Ulna Styloid Styloid process Coronal section of radius process demonstrates how thickness Lunate facet of cortical bone of shaft Scaphoid facet Carpal articular suface diminishes to thin layer over cancellous bone at distal end CHARACTERISTICS OSSIFY FUSE COMMENTS • Cylindrical long bone RADIUS • Anterolateral portion of RH has less sub- • Head is intraarticular chondral bone (susceptible to fracture) • Tuberosity: biceps inserts Primary 8-9wk 14yr • Shaft has a bow Shaft 2-3yr • Tuberosity points ulnarly in supination • Distal end widens, is made Secondary 4yr 16-18yr • Bow allows rotation around ulna Head 16-18yr • Cancellous distal radius common fracture of cancellous bone, has Distal scaphoid & lunate facets, epiphysis site (esp. in peds & older pts) & radial styloid • Distal radius x-ray measurements: 11° • Ulnar (sigmoid) notch: DRUJ Primary ULNA Shaft 8-9wk 16-18yr volar tilt, 22° radial inclination, 11-12mm • Long bone: straight bone radial height • Triangular cross-section Secondary 9yr 16-20yr • Tuberosity: brachialis Olecranon 5-6yr 16-20yr • The radius rotates around the stationary Distal ulna through proximal & distal notches insertion epiphysis during pronation/supination • Proximal: olecranon, coro- • 75% of growth from distal epiphysis noid process, radial • Olecranon & coronoid provide primary (sigmoid) notch • Distal: ulnar styloid bony stability to elbow joint • Coronoid fx can result in instability • Common site of fx (often w/DR fx) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 141

5 Forearm • OSTEOLOGY Metacarpal bones Metacarpal bones 43 2 23 4 5 11 5 Capitate Trapezoid Hook of hamate Tubercle of Capitate Hamate trapezium Trapezoid Pisiform Hamate Triquetrum Trapezium Triquetrum Lunate Tubercle of Trapezium Ulnar scaphoid Radial styloid Pisiform styloid Scaphoid process Lunate process Radial styloid Scaphoid Ulnar Ulna process styloid Dorsal tubercle process Anterior (palmar) view Radius (Lister’s) of the radius Ulnar (sigmoid) Radius Ulna notch Posterior (dorsal) view CHARACTERISTICS OSSIFY FUSE COMMENTS PROXIMAL ROW Scaphoid: boat shape, 80% covered 5th 5yr 14-16yr • Blood supply enters dorsal waist, with articular cartilage (not waist) bridges both rows • #1 carpal fx. Proximal fractures are at risk of nonunion/AVN Lunate: moon shape. Four articulations: 4th 4yr 14-16yr • Dislocations: rare but often missed 1. radius (lunate facet), 2. scaphoid, • Will rotate (carpal instability) if liga- 3. triquetrum, 4. capitate mentous attachments to adjacent bones are disrupted Triquetrum: pyramid shape. Lies 3rd 3yr 14-16yr • 3rd most common carpal fracture under the pisiform and ulnar styloid • Articulates with TFCC Pisiform: large sesamoid bone. 8th 9-10yr 14-16yr • Multiple attachments: FCU, transverse In FCU tendon, anterolateral to carpal ligament (TCL), abductor digiti triquetrum minimi, multiple ligaments DISTAL ROW Trapezium: saddle shape 6th 5-6yr 14-16yr • Has groove for FCR tendon Trapezoid: trapezoidal/wedge shape 7th 6-7yr 14-16yr • Articulates with second metacarpal Capitate: largest carpal bone, 1st carpal 1st 1yr 14-16yr • Keystone to carpal arch, floor of CT bone to ossify • Retrograde blood supply Hamate: has volar-oriented hook that is 2nd 2yr 14-16yr • Hook can fx, ulnar a. can be injured distal and radial to pisiform • TCL attaches border of Guyon’s canal • Ossification: each from a single center in a counter-clockwise direction (anatomic position) starting with the capitate. • Each bone has multiple (4-7) tight articulations with adjacent bones. • Proximal row is considered the “intercalated segment” between the distal radius/TFCC and distal carpal row. • Scaphoid-lunate angle (measured on lateral x-ray): avg. 47° (range 30-60°; Ͻ30ϭVISI, Ͼ60ϭDISI). 142 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

RADIOLOGY • Forearm 5 Capitate Hook of Scaphoid hamate Scapho- Triquetrum lunate interval Pisiform Distal Capitate Lunate pole of Lunate Distal Ulnar scaphoid radius styloid Ulna Pisiform Trapezium Ulna Radius Scaphoid Wrist x-ray, AP Wrist x-ray, lateral Distal radius Capitate Hamate Scaphoid Triquetrum Hook of Lunate hamate Ulna Lunate Pisiform Triquetrum Wrist x-ray, oblique Wrist x-ray, ulnar deviation RADIOGRAPH TECHNIQUE FINDINGS CLINICAL APPLICATION AP (anteroposterior) Lateral Palm down on plate, beam Carpal bones, radiocarpal joint Distal radius, ulnar, carpal Oblique AP-ulnar deviation perpendicular to plate fractures or dislocation Carpal tunnel view Ulnar border of wrist & Alignment of bones, joints Same as above, carpal CT hand on plate (lunate) instability MRI Lateral with 40° rotation Alignment & position of bones Same as above Bone scan AP, deviate wrist ulnarly Isolates scaphoid Scaphoid fractures Maximal wrist extension, Hamate, pisiform, trapezium Fractures (esp. hook of the beam at 15° hamate) OTHER STUDIES Axial, coronal, & sagittal Articular congruity, bone heal- Fractures (scaphoid, hook ing, bone alignment of hamate), nonunions Sequence protocols vary Soft tissues (ligaments, tendons, Occult fractures cartilage), bones (e.g., scaphoid), tears (e.g., TFCC, S-L ligament) All bones evaluated Infection, stress fxs, tumors NETTER’S CONCISE ORTHOPAEDIC ANATOMY 143

5 Forearm • TRAUMA Fracture of Both Forearm Bones Fracture of both radius and ulna with angulation, shortening, and comminution of radius Open reduction and fixation with compression plates and screws through both cortices. Good alignment, with restoration of radial bow and interosseous space. Preoperative radiograph. Fractures of shafts of both forearm bones Postoperative radiograph. Compression plates applied and fragments in good alignment DESCRIPTION EVALUATION CLASSIFICATION TREATMENT RADIUS AND ULNA FRACTURES Both-Bone Fracture • Mech: fall or high energy Hx: Trauma, pain and Descriptive: • Peds (Ͻ10-12y.o.): • Both bones usually frac- swelling, ϩ/Ϫ deformity • Proximal, middle, distal 1⁄3 closed reduction PE: Swelling, tenderness, ϩ/Ϫ • Displaced/angulated and casting ture as energy passes clinical deformity • Comminuted thru both bones XR: AP & lateral forearm • Open or closed • Adults: ORIF (plates • Fractures can be at dif- & screws) through ferent levels separate incisions COMPLICATIONS: Malunion (loss of radial bow leads to decreased pronosupination), decreased range of motion Single-Bone Fracture • Mechanism: direct blow; Hx: Direct blow to forearm Descriptive: • Nondisplaced: cast aka “nightstick fracture” PE: Swelling, tenderness • Displaced, shortened, an- • Displaced: ORIF XR: AP & lateral forearm • Ulna most common gulated, comminuted COMPLICATIONS: Nonunion, malunion 144 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Monteggia Fracture TRAUMA • Forearm 5 In less common type of Monteggia Fractures of proximal fracture, ulna angulated posteriorly ulna often characterized and radial head dislocated posteriorly by anterior angulation of ulna and anterior Galeazzi Fracture dislocation of radial head with C.A. Luce Anteroposterior view of fracture of radius Dislocation of distal radioulnar joint plus dislocation of distal radioulnar joint better demonstrated in lateral view DESCRIPTION EVALUATION CLASSIFICATION TREATMENT MONTEGGIA FRACTURE • Proximal ulna fracture, Hx: Fall, pain and swelling Bado (based on RH location): • Ulna: ORIF (plate/screws) shortening forces result PE: Tenderness, deformity. • I: Anterior (common) • Radial head: closed re- in radial head dislocation Check compartments and • II: Posterior do neurovascular exam • III: Lateral duction (open if irreduc- • Mechanism: direct blow XR: AP/lateral: forearm; • IV: Anterior with associ- ible or unstable) or fall on outstretched also, wrist and elbow • Peds: closed reduction hand ated both-bone fracture and cast COMPLICATIONS: Radial nerve/PIN injury (most resolve), decreased ROM, compartment syndrome, nonunion GALEAZZI FRACTURE • Mechanism: fall on out- Hx: Fall, pain and swelling By mechanism: • Radius: ORIF stretched hand PE: Tenderness, deformity. • Pronation: Galeazzi • DRUJ: closed reduction, Check compartments and • Supination: Reverse • Distal 1⁄3 radial shaft do neurovascular exam ϩ/Ϫ percutaneous pins fracture, shortening XR: AP/lateral forearm: Galeazzi (ulna shaft fx with in supination if unstable forces result in distal ra- ulna usually dorsal. Also, DRUJ dislocation) (open if unstable) dioulnar dislocation wrist and elbow series • Cast for 4-6wk • Peds: reduce & cast COMPLICATIONS: Nerve injury, decreased ROM, nonunion, DRUJ arthrosis NETTER’S CONCISE ORTHOPAEDIC ANATOMY 145

5 Forearm • TRAUMA Frykman Classification of Fractures of Distal Radius IV VI II VIII I III V VII Extraarticular radius: I Radiocarpal intraarticular: III Intraarticular distal Intraarticular radiocarpal Ulnar styloid: II Ulnar styloid: IV radioulnar: V and distal radioulnar: VII Ulnar styloid: VI Ulnar styloid: VIII Reduction of a Colles Fracture Fractures can usually be reduced by closed manipulation. Wrist first dorsiflexed; traction initiated as distal and volar thumb pressure applied over distal fragments With pressure and traction maintained, wrist gently straightened DESCRIPTION EVALUATION CLASSIFICATION TREATMENT DISTAL RADIUS FRACTURE • Nondisplaced: cast • Displaced: • Mechanism: fall on out- Hx: Trauma (usually fall), Frykman (for Colles): stretched hand pain and swelling • Type I, II: extraarticular ‫ ؠ‬Stable: closed PE: Swelling, tenderness, • Type III, IV: RC joint reduction, well- • Very common (Colles #1) ϩ/Ϫ deformity. Do thor- • Type V, VI: RC joint molded cast, 4-6wk • Cancellous bone susceptible ough neurovascular • Type VII, VIII: both radio- exam. ‫ ؠ‬Unstable: closed to fx (incl. osteoporotic fx) XR: Wrist series (3 views) ulnar & radiocarpal reduction, percuta- • Colles (#1): dorsal displace- Normal measurements (RC) joints involved neous pinning ϩ/Ϫ ‫ ؠ‬11° volar tilt • Even # fxs have associ- ext. fix. or ORIF ment (apex volar angulation) ‫ ؠ‬11-12mm radial ated ulnar styloid fx • Smith fx: volar displacement Other fxs, descriptive: • Intraarticular: ORIF • Barton fx: articular rim fx height displaced, angulated (e.g., volar plate) • Radial styloid (“chauffeur fx”) ‫ ؠ‬23º radial inclination CT: For intraarticular fxs • Elderly: cast, early ROM COMPLICATIONS: Malunion, posttraumatic osteoarthritis, stiffness/loss of range of motion 146 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

with TRAUMA • Forearm 5 C.A. Luce Scaphoid Fracture Less common fractures Fracture of middle third (waist) of Tubercle Distal pole scaphoid (most common) Vertical shear Proximal pole Perilunate Dislocation Palmar view shows (A) lunate C Capitate Lateral view shows lunate rotated and displaced volarly, A displaced volarly and rotated. (B) scapholunate space widened, Tuberosity Broken line indicates further (C) capitate displaced proximally B of scaphoid dislocation to volar aspect of and dorsally distal radius Lunate DESCRIPTION EVALUATION CLASSIFICATION TREATMENT SCAPHOID FRACTURE • Mechanism: fall on out- Hx: Trauma (usually Location: • Nondisplaced: 1. Cast- stretched hand fall), pain and swelling • Proximal pole ing (LAC & SAC) aver- PE: “Snuffbox” tender- • Middle/”waist” (#1) age 10-12wk; • Most common carpal fx ness, decreased ROM • Distal pole 2. Percutaneous screw • Retrograde blood suppy XR: Wrist & ulnar devia- tion views Position: • Displaced: ORIF ϩ/Ϫ to proximal pole is in- CT: For most fxs; shows • Displaced bone graft jured in waist fxs, can displacement/pattern • Angulated/shortened lead to nonunion or AVN MR: Occult fx, AVN • Nonunion: ORIF with • Distal pole usually heals tricortical bone graft or • High index of suspicion vascularized bone will decrease missed fxs graft COMPLICATIONS: Nonunion, wrist arthrosis (SLAC wrist from chronic nonunion), osteonecrosis (esp. proximal pole) PERILUNATE INSTABILITY/DISLOCATION • Mech: fall; axial compres- Hx: Trauma/fall, pain Instability (Mayfield (4)) • Instability: closed vs sion & hyperextension PE: Characteristic volar • I: Scapholunate disruption open reduction, percu- “fullness”, decr. ROM • II: Lunocapitate disruption taneous pinning & pri- • Instability progresses XR: S-L gap Ͼ3mm • III: Lunotriquetral disruption mary ligament repair through 4 stages (May- S-L angle: Ͼ60º or • IV: Lunate (peri) dislocation field) as various liga- Ͻ30º Dislocation (Stage 4 instability) • Dislocation: open re- ments are disrupted CT: Evaluate carpal fxs • Lesser arc: ligaments only duction of lunate, per- MR: Shows ligament in- • Greater arc: assoc. carpal fx cutaneous pinning • Dislocation (stage 4) oc- jury in subtle early ϩ/Ϫ ORIF of carpal fx curs through weak spot stages (space of Poirier) • Late/wrist arthrosis: proximal row carpec- • Transscaphoid disloca- tomy or STT fusion tion is #1 injury pattern COMPLICATIONS: Wrist arthrosis (e.g., SLAC from instability), nonunion of fracture, chronic pain and/or instability NETTER’S CONCISE ORTHOPAEDIC ANATOMY 147

5 Forearm • TRAUMA Torus (buckle) fracture of radius Greenstick fractures of radius and ulna DESCRIPTION EVALUATION CLASSIFICATION TREATMENT INCOMPLETE FRACTURE: TORUS AND GREENSTICK FRACTURE • Torus: reduction rarely needed, cast 2-4wk • Common in children (usually Hx: Trauma, pain, inability/ • Torus (buckle): concave 3-12y.o.) unwilling to use hand/ cortex compresses • Greenstick: nondis- extremity (buckles), convex/ placed—SAC 2-4wk. • Mechanism: fall on out- PE: ϩ/Ϫ deformity. Point tension side: intact Reduce if Ͼ10º of stretched hand most common tenderness & swelling angulation—well- XR: AP and lateral. Torus: • Greenstick: concave, molded LAC 3-4wk • Distal radius most common cortical “buckle.” Green- cortex intact or buck- • Increased elasticity of pediat- stick: unicortical fracture led, convex/ tension side fracture or plastic ric bone allows for plastic de- deformity formity and/or unicortical fx COMPLICATIONS: Deformity, malunion, neurovascular injury (rare) 148 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

JOINTS • Forearm 5 Radius Radius Wrist (radiocarpal) joint Midcarpal joint Wrist Carpometacarpal joint (radiocarpal) Palm joint Wrist (radiocarpal) joint Articular disc Hand in Midcarpal joint of wrist joint flexion Lunate Midcarpal joint Capitate Carpometacarpal joint 3rd metacarpal bone Dorsum Palm Carpometacarpal joint Hand in Hand in anatomical extension position Sagittal sections through wrist and Palm middle finger WRIST GENERAL • The wrist is a complex joint comprising 3 main articulations: 1. Radiocarpal (distal radius/TFCC to proximal row), 2. Distal radioulnar joint (DRUJ), 3. Midcarpal (between carpal rows) • Other articulations: pisotriquetral and multiple intercarpal (between 2 adjacent bones in the same row) • Proximal row has no muscular attachments, considered the “intercalated segment,” & responds to transmitted forces. Distal row bones are tightly connected and act as a single unit in a normal wrist. • Range of motion: ‫ ؠ‬Flexion 65-80° (40% from radiocarpal, 60% midcarpal); extension 55-75° (65% radiocarpal, 35% midcarpal) ‫ ؠ‬Radial deviation: 15-25°; ulnar deviation: 30-45° (55% midcarpal, 45% radiocarpal) • Types of ligaments ‫ ؠ‬Extrinsic: connect the distal forearm (radius & ulna) to the carpus ‫ ؠ‬Intrinsic: connect carpal bones to each other (i.e., origin and insertion of ligament both within the carpus) ‫ ؠ‬Interosseous: ligaments connecting carpal bones within the same row (proximal or distal) ‫ ؠ‬Midcarpal/Intercarpal: ligaments connecting carpal bones between the proximal and distal rows. • Palmar (volar) ligaments are stronger and more developed; most are intracapsular. NETTER’S CONCISE ORTHOPAEDIC ANATOMY 149

5 Forearm • JOINTS Short radiolunate ligament Palmar radioulnar ligament Flexor retinaculum removed: Ulnolunate ligament palmar view Ulnocapitate ligament Ulnotriquetral ligament Long radiolunate ligament Lunotriquetral ligament Space of Poirier Triquetrohamate ligament Triquetrocapitate ligament Radioscaphocapitate ligament Scaphotrapeziotrapezoid ligament Capitohamate ligament 5 Scaphocapitate ligment Trapeziotrapezoid ligament Trapeziocapitate ligament 1 2 34 Metacarpal bones LIGAMENTS ATTACHMENTS FUNCTION/COMMENT RADIOCARPAL JOINT Extrinsic—Palmar Superficial Radioscaphocapitate Radius to carpus Blends with UC to form distal border of space of Poirier ‫ ؠ‬Radioscaphoid (RS) Radial styloid to scaphoid Aka “radial collateral” lig. Stabilizes proximal pole ‫ ؠ‬Radiocapitate (RC) Radius to capitate body Forms a fulcrum around which the scaphoid rotates Long radiolunate (lRL) Volar radius to lunate Blends with palmar LT interosseous ligament Ulnocapitate (UC) Ulna/TFC to capitate Blends with RSC laterally. Distal border of space of Short radiolunate (sRL) Distal radius to lunate Poirier Deep Stout & vertical. Prevents dx in hyperextension Ulnolunate (UL) TFC to lunate UL & UT blend with UC to help stabilize the DRUJ Ulnotriquetral (UT) TFC to triquetrum UL & UT considered by some to be part of the TFCC Radioscapholunate Radius to SL joint “Ligament of Testut,” a neurovascular bundle to SL jt. Dorsal radiocarpal (DRC) Extrinsic—Dorsal ‫ ؠ‬Superficial bundle ‫ ؠ‬Deep bundle Radius to lunate/triquetrum Aka radiolunotriquetral (RLT); main dorsal stabilizer Radius to triquetrum The two bundles are typically indistinguishable Radius to LT joint Fibers attach to lunate and/or lunotriquetral ligament • Space of Poirier: weak spot volarly where perilunate dislocations occur (between the proximal edge of RSC & UC liga- ments distally and distal edge of lRL ligament proximally). • No true ulnar collateral ligament exists in the wrist. The ECU & sheath provide some ulnar collateral support. • Deep volar extrinsic ligaments can be seen easily during wrist arthroscopy; the superficial ones are difficult to visualize. • The UC, UL, and UT form the ulnocarpal ligamentous complex. 150 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Posterior (dorsal) view JOINTS • Forearm 5 Dorsal radial metaphyseal arcuate ligament Dorsal radiocarpal ligament (DRC) Dorsal radioulnar ligament Scapholunate dorsal ligament Trapeziotrapezoid ligament Ulnotriquetral ligament (dorsal view) Trapeziocapitate ligament 1 Triquetrohamate ligament Dorsal intercarpal ligament (DIC) Capitohamate ligament 5 4 32 Metacarpal bones LIGAMENTS ATTACHMENTS FUNCTION / COMMENT INTRINSIC LIGAMENTS Triquetrohamocapitate (THC) Triquetrum to: Midcarpal Joint ‫ ؠ‬Triquetrohamate (TH) Hamate ‫ ؠ‬Triquetrocapitate (TC) Capitate Palmar Medial/ulnar portion of arcuate ligament Short, stout ligament Often confluent with the ulnocapitate part (UC) ligament Scaphocapitate (SC) Scaphoid to capitate Stabilizes distal scaphoid. Radial part of arcuate lig. Dorsal intercarpal (DIC) Dorsal Triq. to tpzm./tpzd. A primary dorsal support Scaphotrapeziotrapezoid (STT) Scaph. to tpzm./tpzd. Lateral (radial) and scaphotrapezial joint support Interosseous Joints PROXIMAL ROW: 2 joints. Ligaments are “C” shaped with dorsal and palmar limbs and a membranous portion between. The membrane prevents communication b/w the radiocarpal and midcarpal joints. It does not add stability. 1. Scapholunate (SL) joint: Scaphoid gives a flexion force to the lunate. Arch of motion during ROM: scaphoidϾlunate. 2. Lunotriquetral (LT) joint: Triquetrum provides an extension force to the lunate, which is resisted by the LT. Scapholunate (SL or SLIL) Scaphoid to lunate Dorsal fibers strongest. Disruption: instability, (DISI) Palmar fibers are looser & allow scaphoid rotation Lunotriquetral (LT) Lunate to triquetrum Palmar fibers strongest. Disruption (with DRC ligament in- jury) leads to carpal instability (VISI) DISTAL ROW: 3 joints as below. Strong interosseous ligaments keep distal row moving as a single unit. Trapeziotrapezium Trapezoid to trapezium Each ligament has 3 parts (palmar, dorsal, deep/ Capitotrapezoid Capitate to trapezium interosseous). Distal row ligaments are stronger than in Capitohamate Capitate to hamate proximal row. CH lig. is strongest distal row ligament. Pisotriquetral Articulation Pisohamate Pisiform to hamate Inserts on hook of hamate; part of Guyon’s canal Pisometacarpal Pisiform to 5th MC base Assists in FCU flexion NETTER’S CONCISE ORTHOPAEDIC ANATOMY 151

5 Forearm • JOINTS Carpal tunnel: palmar view Palmaris longus tendon Radius Ulna Ulna Palmar carpal ligament Interosseous Palmar (thickening of deep membrane radioulnar antebrachial fascia) Ulnar artery ligament (cut and reflected) and nerve Flexor carpi Radial artery ulnaris tendon Ulnolunate Palmar and superficial part ulno- palmar branch Flexor digitorum carpal profundus Ulnotri- ligament Flexor carpi tendons quetral radialis tendon Flexor digitorum part superficialis Flexor pollicis tendons Flexor carpi ulnaris longus tendon tendon (cut) Pisiform Median nerve Pisiform Deep palmar Palmar branch of ulnar Pisometacarpal aponeurosis artery and deep ligament branch of ulnar Tubercle of nerve Pisohamate scaphoid ligament Hook of Tubercle of 5 hamate Hook of hamate trapezium Flexor carpi Palmar metacarpal Transverse 1 radialis insertion 4 5 ligaments carpal liga- 23 4 ment (flexor retinaculum) Metacarpal bones Flexor pollicis longus tendon Radiocarpal joint Scapholunate lig. Dorsal scapho- Wrist MRI, axial lunate ligament Scaphoid Dorsal Scaphoid Radioscapho- Lunate Volar capitate lig. scapho- Ulnar lunate Long radio- ligament lunate lig. Ligament styloid Scaphoid fossa (of distal radius) of Testut Scapholunate ridge (radio- Triquetrum scapho- Lunate Volar lunate) Flexor tendons in carpal tunnel Lunate fossa (of distal radius) Triangular fibrocartilage complex Wrist MRI, coronal Prestyloid recess Ulnar styloid Triquetrum Triquetrum ECU sheath Lunate Ulnotriquetral lig. Triangular Scaphoid Palmar distal fibrocartilage radioulnar lig. (disc) Triangular fibrocartilage Ulnolunate Dorsal distal complex lig. radioulnar lig. Distal radius Lunate fossa Ulna (of distal radius) 152 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

JOINTS • Forearm 5 Triquetrum ECU tendon Lunate Meniscus homologue Ulnotriquetral lig. Prestyloid recess Ulnolunate lig. Palmar radioulnar lig. Articular disc Dorsal radioulnar lig. ECU tendon sheath Ulna Radius LIGAMENTS ATTACHMENTS FUNCTION / COMMENT DISTAL RADIOULNAR JOINT • This joint (DRUJ) is stabilized by a combination of structures that form the triangular fibrocartilage complex (TFCC). • Primary motion is pronation (60-80°) & supination (60-85°); the radius rotates around the stationary ulna. • 20% of an axial load is transmitted to ulna in an ulnar neutral wrist. The ulna takes more load when it is ulna positive. Triangular Fibrocartilage Complex • TFCC is interposed between the distal ulna and the ulnar proximal carpal row (triquetrum). It originates at the articular margin of the sigmoid notch (radius) and inserts at the base of the ulnar styloid. • Vascular supply to TFCC (from ulnar artery & anterior interosseous artery) penetrate the peripheral 10%-25%. Triangular fibrocartilage Radius to ulna fovea (deep fibers) & TFC has 3 portions: central disc and styloid (superficial fibers) 2 peripheral (radioulnar) ligaments ‫ ؠ‬Central (articular) disc Blends w/ radial articular cartilage Resists compression and tension; avascular and aneural ‫ ؠ‬Dorsal radioulnar Dorsal radius to ulnar fovea Blends with TFC, tight in pronation, loose in (ligamentum subcruentum) supination ‫ ؠ‬Palmar radioulnar Volar radius to ulnar fovea Blends with TFC, tight in supination, loose in (ligamentum subcruentum) pronation Meniscal homologue Dorsal radius to volar triquetrum Highly vascular synovial fold ECU tendon sheath Ulna styloid, triquetrum, hamate Considered an “ulnar collateral ligament” Other • UL, UT, and prestyloid recess are considered by some to be a part of the TFCC. Ulnolunate (UL) TFC to lunate UL & UT blend with ulnocapitate lig. to contrib- Ulnotriquetral (UT) TFC to triquetrum ute to fxn of TFCC and stabilize the DRUJ. Prestyloid recess None Between palmar radioulnar ligament & menis- cus homologue • Other structures contributing to DRUJ stability: ECU, pronator quadratus, interosseous membrane. • TFCC can be torn (degenerative or traumatic). Peripheral tears can be repaired, central tears need debridement. NETTER’S CONCISE ORTHOPAEDIC ANATOMY 153

5 Forearm • TUNNELS Carpal tunnel Flexor Median n. Ulnar n. in Transverse carpal tendons Palmar cutaneous Guyon’s canal branch of median n. lig. (roof of carpal Transverse Flexor tendons carpal lig. Thenar mm. in carpal tunnel tunnel) Median n. in Abductor pollicis brevis Carpal carpal tunnel tunnel Opponens pollicis Flexor pollicis brevis (superficial head) 1st and 2nd lumbrical mm. Ulnar nerve Ulnar tunnel Digital nn. Ulnar tunnel Volar carpal Transverse Zone I (motor Palmaris ligament carpal and sensory) brevis m. ligament Zone II Pisiform (motor) Ulnar n. Ulnar a. Zone III (sensory) STRUCTURE COMPONENTS COMMENTS CARPAL TUNNEL Transverse carpal Attachments: • Roof of carpal tunnel, can compress median nerve. ligament (TCL, Medial: pisiform and hamate TCL is incised in a carpal tunnel release. flexor retinacu- Lateral: scaphoid and trapezium lum) • Tunnel is narrowest at hook of hamate Borders Roof: transverse carpal ligament • See above Floor: central carpal bones • Especially capitate and trapezoid Medial wall: pisiform and hamate • Hook of hamate gives medial wall Lateral wall: trapezium and scaphoid • Trapezium is primary wall structure Contents Tendons: FDS (4), FDP (4), FPL • 9 tendons within the carpal tunnel Nerve: median • Compressed in carpal tunnel syndrome • Thenar motor branch of median nerve can exit under, through, or distal to the transverse carpal ligament. • A persistent median artery or aberrant muscle can occur in the tunnel and may cause carpal tunnel syndrome. ULNAR TUNNEL / GUYON’S CANAL Borders Floor: transverse carpal ligament • Can be released simultaneously with CTR Roof: volar carpal ligament • Continuous with deep antebrachial fascia Medial wall: pisiform • Neurovascular bundle is under pisohamate ligament Lateral wall: hook of hamate • Fracture can cause nerve compression. Contents Ulnar nerve • Divides in canal to deep & superficial branches Ulnar artery • Terminates as superficial arch around hamate • Fractures (malunion) or masses (e.g., ganglion cysts #1) can compress the ulnar nerve or artery within the canal. 154 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

OTHER STRUCTURES • Forearm 5 Posterior (dorsal) Extensor carpi ulnaris— Compartment 6 view Extensor digiti minimi — Compartment 5 Plane of cross section shown below Extensor digitorum Compartment 4 Extensor indicis Extensor retinaculum Abductor digiti Extensor pollicis longus — Compartment 3 minimi muscle Extensor carpi radialis brevis Compartment 2 Intertendinous connections Extensor carpi radialis longus (junctura tendinae) Abductor pollicis longus Compartment 1 Extensor pollicis brevis Radial artery in anatomical snuffbox Dorsal interosseous muscles Transverse fibers of extensor expansions (hoods) Cross section of most distal portion of forearm Extensor retinaculum Extensor digitorum and Extensor pollicis longus — Compartment 3 extensor indicis Compartment 4 Extensor carpi radialis brevis Compartment 5 Extensor Compartment 2 digiti minimi Extensor carpi radialis longus Extensor 5 4 32 Extensor Compartment 1 Compartment 6 carpi 6 1 pollicis brevis ulnaris Ulna Radius Abductor pollicis longus STRUCTURE FUNCTION COMMENTS EXTENSOR COMPARTMENTS Extensor retinaculum Covers the wrist dorsally Forms six fibro-osseous compartments through which the extensor tendons pass Number Tendon Clinical Condition Dorsal compartments I EPB, APL de Quervain’s tenosynovitis can develop here II ECRL, ECRB Tendinitis can occur here III EPL Travels around Lister’s tubercle, can rupture IV EDC, EIP This compartment split in dorsal wrist approach V EDQ (EDM) Rupture (Jackson-Vaughn syndrome) in RA VI ECU Tendon can snap over ulnar styloid causing pain • EIP and EDQ tendons are ulnar to EDC tendons to the index and small fingers, respectively. • 1st compartment may have multiple slips that all need to be released in de Quervain’s disease for a full release. NETTER’S CONCISE ORTHOPAEDIC ANATOMY 155

5 Forearm • MINOR PROCEDURES Carpal Tunnel Injection Wrist Injection Lister’s Extensor Palmaris longus tubercle pollicis tendon longus tendon Median nerve Ulnar nerve Extensor Dorsal carpi radialis branch longus of ulnar tendon nerve Extensor carpi radialis brevis tendon Superficial radial nerve STEPS WRIST ASPIRATION/INJECTION 1. Ask patient about allergies 2. Palpate radiocarpal joint dorsally, find Lister’s tubercle and the space ulnar to it 3. Prep skin over dorsal wrist (iodine/antiseptic soap) 4. Anesthetize skin locally (quarter size spot) 5. Aspiration: insert 20-gauge needle into space ulnar to Lister’s tubercle/EPL/ECRB and radial to EDC, aspirate. Injection: insert 22-gauge needle into same space, aspirate to ensure not in vessel, then inject 1-2ml of local or local/steroid preparation into RC joint. 6. Dress injection site 7. If suspicious for infection, send fluid for Gram stain and culture CARPAL TUNNEL INJECTION/MEDIAN NERVE BLOCK 1. Ask patient about allergies 2. Ask patient to pinch thumb and small finger tips; palmaris longus (PL) tendon will protrude (10% -20% do not have one). Median nerve is beneath PL, just ulnar to FCR within the carpal tunnel. 3. Prep skin over volar wrist (iodine/antiseptic soap) 4. Anesthetize skin locally (quarter size spot) 5. Insert 22-gauge or smaller needle into wrist ulnar to PL at flexion crease at 45º angle. Aspirate to ensure needle is not in a vessel. Inject 1-2ml of local or local/steroid preparation. 6. Dress injection site WRIST BLOCK Four separate nerves are blocked. Based on the necessary anesthesia, a complete or partial block can be performed: 1. Ask patient about allergies 2. Prep skin over each landmark (iodine/antiseptic soap) 3. Ulnar nerve: palpate the FCU tendon just proximal to volar wrist crease. Insert needle under the FCU tendon. Aspirate to ensure needle is not in ulnar artery (nerve is ulnar to the artery). Inject 3-4ml of local anesthetic into the space dorsal to the FCU tendon. 4. Dorsal cutaneous branch of ulnar nerve: palpate the distal ulna/styloid. Inject a large subcutaneous wheal on the dorsal and ulnar aspect of the wrist, just proximal to the ulnar styloid. 5. Superficial radial nerve: block at radial styloid with a large subcutaneous wheal on the dorsoradial aspect of the wrist. 6. Median nerve: block in carpal tunnel as described above 7. Palmar cutaneous branch of median nerve: raise a wheal over the central volar wrist. • Median and superficial radial nerve blocks are effective for thumb, index finger, and most middle finger injuries. • Ulnar and dorsal cutaneous branch blocks are used for small finger injuries. Most ring finger injuries require complete wrist block. 156 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

HISTORY • Forearm 5 Fracture/dislocation Distal radius and scaphoid fractures commonly result from fall on outstretched hand Repetitive Use of motion power tools Flexed wrist position Pressure aginst hard surface Abnormal work postures may lead to compression neuropathies QUESTION ANSWER CLINICAL APPLICATION 1. Age Young Trauma: fractures and dislocations, ganglions 2. Pain Middle aged, elderly Arthritis, nerve entrapments, overuse a. Onset b. Location Acute Trauma Chronic Arthritis 3. Stiffness Dorsal Kienböck’s disease, ganglion Volar Carpal tunnel syndrome (CTS), ganglion (esp. radiovolar) 4. Swelling Radial Scaphoid fracture, de Quervain’s tenosynovitis, arthritis Ulnar Triangular fibrocartilage complex (TFCC) tear, tendinitis 5. Instability (e.g., ECU) 6. Mass With dorsal pain 7. Trauma With volar pain (at night) Kienböck’s disease 8. Activity Carpal tunnel syndrome 9. Neurologic Joint: after trauma Joint: no trauma Fracture or sprain symptoms Along tendons Arthritides, infection, gout Flexor or extensor tendinitis (calcific), de Quervain’s disease 10. History of Popping, snapping arthritides Carpal instability (e.g., scapholunate dislocation) Along wrist joint Ganglion Fall on hand Fractures: distal radius, scaphoid; dislocation: lunate; TFCC tear Repetitive motion (e.g., typing) CTS, de Quervain’s tenosynovitis Numbness, tingling Nerve entrapment (e.g., CTS), thoracic outlet syndrome, Weakness radiculopathy (cervical spine) Nerve entrapment (median, ulnar, radial) Multiple joints involved Arthritides NETTER’S CONCISE ORTHOPAEDIC ANATOMY 157

5 Forearm • PHYSICAL EXAM Distal Radius Fracture Scaphoid Fracture Carpal Dislocation Clinical findings. Pain, tenderness, and swelling in anatomic snuffbox Clinical appearance of Typical deformity. Anterior deformity due to severely bulge of dislocated lunate displaced fracture of distal radius de Quervain’s with Ganglion Cyst Disease C.A. Luce Firm, rubbery, sometimes lobulated swelling Point of exquisite over carpus, most prominent on flexion of tenderness over Carpal Tunnel Syndrome wrist. Broken line indicates styloid process of line of skin incision radius and sheath Thenar of involved tendons atrophy EXAMINATION TECHNIQUE CLINICAL APPLICATION Gross deformity INSPECTION Swelling Fractures, dislocations: forearm and wrist Wasting Bones and soft tissues Ganglion cyst Skin changes Especially dorsal or radial Trauma (fracture/dislocation), infection Radial and ulnar styloids Diffuse Peripheral nerve compression (e.g., CTS) Carpal bones Loss of muscle Infection, gout Soft tissues PALPATION Neurovascular compromise Warm, red Tenderness may indicate fracture Cool, dry Snuffbox tenderness: scaphoid fracture; lunate Palpate each separately tenderness: Kienböck’s disease Both proximal and distal row Scapholunate dissociation Tenderness: pisotriquetral arthritis or FCU Proximal row tendinitis Pisiform Tenderness over 1st compartment: de Quervain’s disease 6 dorsal extensor compartments Tenderness indicates TFCC injury Firm/tense compartments ϭ compartment synd. TFCC: distal to ulnar styloid Compartments 158 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

PHYSICAL EXAM • Forearm 5 90˚ 75˚ Wrist range of motion deviation Radial 0˚ Ulnar Extension rotation deviation 20˚ 30˚ 0˚ Flexion 90˚ 80˚ 90˚ 90˚ EXAMINATION TECHNIQUE CLINICAL APPLICATION Flex and extend RANGE OF MOTION Radial/ulnar deviation Flex (toward palm), extend Normal: flexion 80°, extension 75° Pronate and supinate opposite Lateral cutaneous nerve In same plane as the palm Normal: radial 15-25°, ulnar 30-45° of forearm (C6) Medial cutaneous nerve Flex elbow 90°, rotate Normal: supinate 90°, pronate 80-90° (only 10-15° in of forearm (T1) wrist wrist; most motion is in elbow) Posterior cutaneous nerve of forearm NEUROVASCULAR Radial nerve (C6-7) Sensory PIN (C6-7) Ulnar nerve (C8) Lateral forearm Deficit indicates corresponding nerve/root lesion Median nerve (C7) Median nerve (C6) Medial forearm Deficit indicates corresponding nerve/root lesion Musculocutaneous (C6) Posterior forearm Deficit indicates corresponding nerve/root lesion C6 Motor Resisted wrist extension Weakness ϭ ECRL/B or corresponding nerve/root lesion Resisted ulnar deviation Weakness ϭ ECU or corresponding nerve/root lesion Resisted wrist flexion Weakness ϭ FCU or corresponding nerve/root lesion Resisted wrist flexion Weakness ϭ FCR or corresponding nerve/root lesion Resisted pronation Weakness ϭ pronator teres or corresponding nerve/ root lesion Resisted supination Weakness ϭ biceps or corresponding nerve/root lesion Reflex Brachioradialis Hypoactive/absence indicates corresponding radiculopathy Pulses Radial, ulnar Diminished/absent ϭ vascular injury or compromise (perform Allen test) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 159

5 Forearm • PHYSICAL EXAM Phalen’s test (wrist flexion) Tinel’s sign Carpal compression test Provocative tests elicit paresthesias in hand. Scaphoid shift test Radial deviation The Finkelstein test exacerbates the pain; it is performed by flexing the thumb and then placing the wrist in ulnar deviation. The thumb Ulnar deviation applies dorsal pressure on the scaphoid tubercle EXAMINATION TECHNIQUE CLINICAL APPLICATION / DDX Durkan carpal SPECIAL TESTS compression Phalen test Manual pressure on median nerve at Reproduction of symptoms (e.g., tingling, numbness): Tinel carpal tunnel median nerve compression (most sensitive test for Finkelstein carpal tunnel syndrome [CTS]) “Piano key” Watson (scaphoid Flex both wrists for 1minute Reproduction of symptoms (e.g., tingling): median n. shift) compression (CTS) Allen test Tap volar wrist (CT/TCL) Reproduction of symptoms (e.g., tingling): median n. compression (CTS) Flex thumb into palm, ulnarly deviate Pain in 1st dorsal compartment (APL/EPB tendons) the wrist suggests de Quervain’s tenosynovitis Stabilize ulnar and translate radius Laxity or subluxation (click) indicates instability of DRUJ dorsal and volar Push dorsally on distal pole of scaph- A click or clunk (scaphoid subluxating dorsally over rim oid, bring wrist from ulnar to radial of distal radius) is positive for carpal instability deviation (scapholunate dissociation) Occlude both radial and ulnar arteries Delay or absence of “pinking up” of the palm and fin- manually, pump fist, then release gers suggests arterial compromise of the artery one artery only released 160 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: ORIGINS AND INSERTIONS • Forearm 5 Anterior (volar) Brachioradialis muscle Brachialis muscle Extensor carpi radialis longus muscle Pronator teres muscle (humeral head) Extensor carpi radialis brevis, Common Common Pronator teres, flexor extensor digitorum, extensor extensor flexor carpi radialis, palmaris digiti minimi, extensor carpi tendon tendon longus, flexor carpi ulnaris, ulnaris muscles flexor digitorum superficialis (humeroulnar head) muscles Brachialis muscle Biceps brachii muscle Flexor digitorum superficialis muscle (humeroulnar head) Pronator teres muscle (ulnar head) Supinator muscle Flexor digitorum profundus muscle Flexor digitorum superficialis muscle (radial head) Pronator teres muscle Flexor pollicis longus muscle Ulna Radius Pronator quadratus muscle Pronator quadratus muscle Note: Attachments of intrinsic Brachioradialis muscle muscles of hand not shown Abductor pollicis longus muscle Flexor carpi ulnaris muscle Flexor carpi radialis muscle Extensor carpi ulnaris muscle Flexor pollicis Flexor digitorum superficialis muscle longus muscle Flexor digitorum profundus muscle Origins Insertions PROXIMAL ULNA PROXIMAL RADIUS ANTERIOR Origins Flexor digitorum superficialis (1 head) Flexor digitorum superficialis (1 head) Pronator teres Supinator Flexor digitorum profundus Insertions Brachialis Biceps Supinator NETTER’S CONCISE ORTHOPAEDIC ANATOMY 161

5 Forearm • MUSCLES: ORIGINS AND INSERTIONS Posterior (dorsal) Note: Attachments of intrinsic Triceps brachii muscle (medial head) muscles of hand not shown Triceps brachii tendon Flexor carpi ulnaris muscle (humeral Anconeus muscle origin via common flexor tendon) Biceps brachii muscle Supinator muscle Flexor carpi ulnaris muscle (ulnar origin) Flexor digitorum profundus muscle Abductor pollicis longus muscle Pronator teres muscle Extensor carpi ulnaris muscle (ulnar origin) Extensor pollicis brevis muscle Extensor pollicis longus muscle Extensor indicis muscle Radius Ulna Extensor carpi radialis longus muscle Brachioradialis muscle Extensor carpi radialis brevis muscle Abductor pollicis longus muscle Extensor carpi ulnaris muscle Extensor pollicis brevis muscle Extensor digitorum muscle (central bands) Extensor pollicis longus muscle Extensor indicis muscle Extensor digiti minimi muscle Extensor digitorum muscle (lateral bands) Origins Insertions PROXIMAL ULNA PROXIMAL RADIUS POSTERIOR Flexor carpi ulnaris Flexor digitorum profundus Origins Supinator none Triceps Insertions Anconeus Biceps Supinator 162 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: ANTERIOR COMPARTMENT • Forearm 5 Biceps brachii muscle Medial cutaneous nerve of forearm Ulnar nerve Brachial artery and median nerve Triceps brachii muscle Medial intermuscular septum Lateral cutaneous nerve of forearm Ulnar artery (terminal musculocutaneous nerve) Medial epicondyle of humerus Brachialis muscle Common flexor tendon Biceps brachii tendon Pronator teres muscle Radial artery Flexor carpi Superficial Bicipital aponeurosis radialis muscle flexor (lacertus fibrosus) [FCR] muscles Brachioradialis muscle Palmaris longus Extensor carpi radialis muscle [PL] longus muscle [ECRL] Flexor carpi Extensor carpi radialis ulnaris muscle brevis muscle [ECRB] [FCU] Flexor pollicis longus Flexor digitorum muscle and tendon superficialis muscle [FPL] [FDS] Radial artery Palmaris longus tendon Dorsal cutaneous branch of ulnar nerve Median nerve Ulnar artery and nerve Palmar carpal ligament Flexor digitorum superficialis tendons (continuous with Pisiform extensor retinaculum) Palmar cutaneous branch of median nerve Thenar muscles Hypothenar muscles Palmar aponeurosis MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT Pronator teres (PT) Medial epicondyle SUPERFICIAL FLEXORS Pronate and Can compress me- Humeral head Proximal ulna flex forearm dian nerve (prona- Ulnar (deep) head Medial epicondyle Lateral radius Median tor syndrome) middle 1⁄3 Flex wrist, ra- Flexor carpi Medial epicondyle dial deviation Radial artery is im- radialis (FCR) Base of 2nd (and Median mediately lateral Palmaris longus 1. Medial 3rd) metacarpal Median Flex wrist (PL) epicondyle Used for tendon Flexor retinaculum/ Flex wrist, ulnar transfers, 10% Flexor carpi ulnaris 2. Posterior ulna palmar aponeurosis deviation congenitally absent (FCU) Pisiform, hook of Ulnar Most powerful wrist hamate, 5th MC flexor. May com- press ulnar nerve NETTER’S CONCISE ORTHOPAEDIC ANATOMY 163

5 Forearm • MUSCLES: ANTERIOR COMPARTMENT Biceps brachii muscle Ulnar nerve Brachialis muscle Median nerve Lateral cutaneous nerve of forearm (cut) Brachial artery (from musculocutaneous nerve) Medial intermuscular septum (Common) radial nerve Deep branch Pronator teres muscle (humeral head) (cut and reflected) Superficial branch Medial epicondyle Biceps brachii tendon Flexor carpi radialis and palmaris longus tendons (cut) Radial recurrent artery Anterior ulnar recurrent artery (Leash of Henry) Flexor digitorum superficialis Radial artery muscle (humeroulnar head) Ulnar artery Supinator muscle Common interosseous artery Brachioradialis muscle Pronator teres muscle (ulnar head) (cut) Pronator teres muscle (cut) Flexor digitorum superficialis Anterior interosseous artery muscle (radial head) [FDS] Flexor carpi ulnaris muscle Flexor pollicis longus muscle Flexor digitorum superficialis [FDS] muscle Palmar carpal ligament (continuous with extensor Ulnar artery retinaculum) with palmaris longus tendon (cut and reflected) Ulnar nerve and dorsal cutaneous branch Flexor carpi radialis Median nerve tendon (cut) Palmar cutaneous branches of median and ulnar nerves (cut) Superficial palmar branch Pisiform of radial artery Deep palmar branch of ulnar artery and deep branch of ulnar nerve Superficial branch of ulnar nerve Transverse carpal ligament (flexor retinaculum) MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT SUPERFICIAL FLEXORS Sublimus test will isolate and Flexor digito- 1. Medial epicondyle Middle phalan- Median Flex PIPJ (also test function rum superfici- proximal ulna ges of digits flex digit and alis (FDS) (not thumb) wrist) 2. Anteroproximal radius FDS is often considered a “middle flexor” because of its position between muscles. 164 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: ANTERIOR COMPARTMENT • Forearm 5 Brachialis muscle Ulnar nerve Musculocutaneous nerve Median nerve (becomes) Brachial artery Lateral cutaneous nerve of forearm Medial intermuscular septum Lateral intermuscular septum Pronator teres muscle Radial nerve (cut and reflected) Lateral epicondyle Anterior ulnar recurrent artery Biceps brachii tendon (cut) Medial epicondyle of humerus Radial recurrent artery Flexor carpi radialis, palmaris longus, Radial artery flexor digitorum superficialis (humeroulnar head), and Supinator muscle flexor carpi ulnaris muscles (cut) Posterior and anterior interosseous arteries Flexor digitorum superficialis Posterior ulnar recurrent artery muscle (radial head) (cut) Ulnar artery Common interosseous artery Pronator teres muscle (cut and reflected) Radial artery Pronator teres muscle (ulnar head) (cut) Median nerve (cut) Flexor pollicis longus [FPL] Flexor digitorum profundus muscle [FDP] muscle and tendon (cut) Radius Pronator quadratus muscle [PQ] Anterior interosseous artery and nerve Brachioradialis tendon (cut) Ulnar nerve and dorsal cutaneous branch Radial artery and Palmar carpal branches of radial and ulnar arteries superficial palmar branch Flexor carpi ulnaris tendon (cut) [FCU] Flexor pollicis longus tendon (cut) [FPL] Pisiform Flexor carpi radialis Deep palmar branch of ulnar artery tendon (cut) [FCR] and deep branch of ulnar nerve Hook of hamate Abductor pollicis longus tendon [APL] 5th metacarpal bone Extensor pollicis brevis tendon [EPB] 1st metacarpal bone MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT DEEP FLEXORS Flex DIPJ Avulsion: Jersey finger (also flex Flexor digitorum Anterior ulna & Distal phalanx Median/AIN digit and Profundus test will iso- profundus (FDP) interosseous (IF, ϩ/Ϫ MF) Ulnar wrist) late and test function membrane Distal phalanx Flex thumb IP FDP and FPL are most (RF, SF, ϩ/Ϫ MF) susceptible to Volk- Pronate mann’s contracture Flexor pollicis Anterior radius Distal phalanx Median/AIN forearm Primary pronator longus (FPL) & proximal of thumb (initiates pronation) ulna Pronator quadra- Medial distal Anterior distal Median/AIN radius tus (PQ) ulna • AIN innervates all three deep flexors. It is tested by making “OK” signs. NETTER’S CONCISE ORTHOPAEDIC ANATOMY 165

5 Forearm • MUSCLES: POSTERIOR COMPARTMENT Superior ulnar collateral artery Triceps brachii muscle (anastomoses distally with Brachioradialis muscle posterior ulnar recurrent artery) Extensor carpi radialis longus (ECRL) muscle Common extensor tendon Ulnar nerve Extensor carpi radialis brevis (ECRB) muscle Extensor digitorum (EDC) muscle Medial epicondyle of humerus Olecranon of ulna Anconeus muscle Flexor carpi ulnaris muscle Extensor carpi ulnaris (ECU) muscle Extensor digiti minimi (EDM) muscle Abductor pollicis longus muscle Extensor retinaculum Extensor pollicis brevis muscle (compartments numbered) Extensor pollicis longus tendon Dorsal cutaneous branch of ulnar nerve Extensor carpi radialis brevis tendon Extensor carpi radialis longus tendon Extensor carpi ulnaris tendon Extensor digiti minimi tendon 6 5 4 321 Superficial branch of radial nerve Extensor digitorum tendons Abductor pollicis longus tendon Extensor indicis tendon Extensor pollicis brevis tendon Extensor pollicis longus tendon 5th metacarpal bone Anatomical snuffbox MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT SUPERFICIAL EXTENSORS Forearm Muscular plane in extension Kocher approach Anconeus Posterior-lateral Posterior-proximal Radial Digit extension Tendon avulsion: epicondyle ulna P2: boutonniere Extensor digito- SF extension P3: mallet finger rum commu- Lateral MCP: Sag. band Radial-PIN Aka EDQ: In 5th nis (EDC) epicondyle P2: Central slip Hand extension dorsal compartment P3: Term. insert and adduction Can cause painful Extensor digiti Lateral snapping over ulna minimi (EDM) epicondyle Same as above in Radial-PIN Forearm flexion small finger Wrist extension Is a deforming force Extensor carpi Lateral in radius fractures ulnaris (ECU) epicondyle Base of 5th MC Radial-PIN Aka ECRL Mobile Wad ECRB degenerates in tennis elbow Brachioradialis Lateral condyle Lateral distal Radial (BR) radius Radial Extensor carpi Lateral condyle Base of 2nd MC radialis longus Extensor carpi Lateral Base of 3rd MC Radial-PIN Wrist extension radialis brevis epicondyle 166 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: POSTERIOR COMPARTMENT • Forearm 5 Branches of Superior ulnar collateral Middle collateral branch of brachial artery Inferior ulnar collateral deep artery of arm (posterior branch) Lateral intermuscular septum Medial intermuscular septum Brachioradialis muscle Ulnar nerve Extensor carpi radialis longus muscle Posterior ulnar recurrent artery Medial epicondyle of humerus Lateral epicondyle of humerus Triceps brachii tendon (cut) Common extensor tendon (partially cut) Olecranon of ulna Extensor carpi radialis brevis muscle Anconeus muscle Supinator muscle Flexor carpi ulnaris muscle Deep branch of radial nerve Recurrent interosseous artery Pronator teres muscle (slip of insertion) Posterior interosseous artery Radius Posterior interosseous nerve Ulna Extensor pollicis longus (EPL) muscle Abductor pollicis longus (APL) muscle Extensor indicis (EIP) muscle Extensor pollicis brevis (EPB) muscle Anterior interosseous artery (termination) 6 5 4 321 Extensor carpi radialis brevis tendon Extensor carpi radialis longus tendon Extensor carpi ulnaris tendon (cut) Extensor digiti minimi tendon (cut) Radial artery Extensor digitorum 1st metacarpal bone communis tendons (cut) 2nd metacarpal bone Extensor retinaculum (compartments numbered) 1st dorsal interosseous muscle 5th metacarpal bone MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT Supinator Posterior medial DEEP EXTENSORS ulna Abductor pollicis Proximal lateral Radial-PIN Forearm supina- PIN pierces muscles, longus (APL) Posterior radius/ radius tion can be compressed ulna Extensor pollicis Base of 1st Radial-PIN Abduct and ex- de Quervain’s dis- brevis (EPB) Posterior radius thumb meta- tend thumb ease (may have Extensor pollicis carpal (CMCJ) multiple slips) longus (EPL) Posterior ulna Extensor indicis Base of thumb Radial-PIN Extend thumb Radial border of proprius (EIP) Posterior ulna prox. phalanx (MCPJ) snuffbox Base of thumb Radial-PIN Extend thumb Tendon turns 45° on distal phalanx (IPJ) Lister’s tubercle Same as EDC Radial-PIN Index finger Ulnar to EDC tendon; & EDM extension last PIN muscle NETTER’S CONCISE ORTHOPAEDIC ANATOMY 167

5 Forearm • MUSCLES: CROSS SECTIONS Median antebrachial vein Flexor digitorum superficialis muscle (radial head) Pronator teres muscle Anterior branch of medial cutaneous Radial artery and superficial branch of radial nerve nerve of forearm Radius Flexor pollicis longus muscle Interosseous membrane Brachioradialis muscle Flexor carpi radialis muscle Ulnar artery and median nerve Lateral cutaneous nerve of forearm Palmaris longus muscle (from musculocutaneous nerve) Flexor digitorum superficialis muscle (humeroulnar head) Supinator muscle Radius Common interosseous artery Ulnar nerve Deep branch of radial nerve (PIN) Flexor carpi ulnaris muscle Extensor carpi radialis longus muscle Basilic vein Flexor digitorum profundus muscle Extensor carpi radialis brevis muscle Extensor digitorum muscle Ulna and antebrachial fascia Anconeus muscle Extensor digiti minimi muscle Posterior cutaneous nerve of forearm (from radial nerve) Extensor carpi ulnaris muscle Palmaris longus muscle Flexor carpi radialis muscle Flexor digitorum superficialis muscle Median nerve Brachioradialis muscle Ulnar artery and nerve Radial artery and superficial Flexor carpi ulnaris muscle branch of radial nerve Anterior interosseous artery and nerve (AIN) Flexor pollicis longus muscle (from median nerve) Extensor carpi radialis longus Flexor digitorum profundus muscle muscle and tendon Ulna and antebrachial fascia Radius Interosseous membrane and extensor Extensor carpi radialis brevis pollicis longus muscle muscle and tendon Posterior interosseous artery and nerve (PIN) Abductor pollicis longus muscle (continuation of deep branch of radial nerve) Extensor digitorum muscle Palmaris longus tendon Extensor digiti minimi muscle Median nerve Flexor digitorum superficialis muscle and tendons Extensor carpi ulnaris muscle Flexor carpi ulnaris muscle and tendon Flexor carpi radialis tendon Radial artery Ulnar artery and nerve Brachioradialis tendon Dorsal cutaneous branch of ulnar nerve Abductor pollicis longus tendon Flexor digitorum profundus muscle and tendons Superficial branch Antebrachial fascia of radial nerve Ulna Extensor pollicis Extensor carpi ulnaris tendon brevis tendon Pronator quadratus muscle and interosseous membrane Extensor carpi radialis Extensor indicis muscle and tendon longus tendon Extensor digiti minimi tendon Extensor carpi radialis brevis tendon Extensor digitorum tendons (common tendon to digits 4 and 5 at this level) Flexor pollicis longus muscle Extensor pollicis longus tendon STRUCTURE RELATIONSHIP RELATIONSHIPS Ulnar nerve/artery Run under FDS on top of FDP muscles, ulnar to the artery Superior radial nerve Runs under the brachioradialis muscle/tendon, radial to the artery Radial artery Is radial (lateral) to FCR muscle and tendon Median nerve Is radial (lateral) to ulnar nerve, runs between FDP and FPL muscles into the carpal tunnel Post. interosseous Pierces supinator muscle proximally, runs between APL & EPL along interosseous membrane nerve (PIN) 168 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: COMPARTMENTS • Forearm 5 Incisions for Compartment Syndrome of Forearm and Hand Wick catheter in volar compartment Volar incision Antebrachial (encircling) fascia Radial a. and superficial Median n. branch of radial n. Ulnar a. and n. Antebrachial (encircling) fascia Radius Anterior interosseous a. and n. Dorsal interosseous a. and n. Interosseous membrane Deep branch of radial n. Wick catheter in dorsal compartment Ulna Dorsal incision Section through midforearm Volar Dorsal forearm incision forearm incision Note: fascial in- Hand incisions (for cisions are the decompression of same lines as interosseous muscles) skin incisions STRUCTURE CONTENTS Superficial COMPARTMENTS Middle Deep Anterior Pronator teres (PT), flexor carpi radialis (FCR), palmaris longus (PL), flexor carpi ulnaris (FCU) Superficial Flexor digitorum superficialis (FDS) Deep Flexor digitorum profundus (FDP), flexor pollicis longus (FPL), pronator quadratus (PQ) Palmar incision Posterior Dorsal incision Anconeus, ext. digit. communis (EDC), ext. digit. minimi (EDM), ext. carpi ulnaris (ECU) Supinator, abd. poll. longus (APL), ext. poll. brevis (EPB), ext. poll. longus (EPL), ext. indicis proprius (EIP) Mobile Wad Brachioradialis, extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB) FASCIOTOMIES Releases the entire anterior compartment Releases the entire posterior compartment and mobile wad NETTER’S CONCISE ORTHOPAEDIC ANATOMY 169

5 Forearm • NERVES Anterior view Musculocutaneous nerve Median nerve (C[5], 6, 7, 8, T1) Medial Cords of Inconstant contribution Posterior brachial Lateral plexus Pronator teres muscle (humeral head) Articular branch Medial brachial cutaneous nerve Flexor carpi radialis muscle Palmaris longus muscle Medial antebrachial cutaneous nerve Pronator teres muscle (ulnar head) Flexor digitorum superficialis muscle Axillary nerve (turned up) Radial nerve Ulnar nerve Flexor digitorum profundus muscle (lateral part supplied by median [anterior interosseous] nerve; medial part supplied by ulnar nerve) Anterior interosseous nerve Flexor pollicis longus muscle BRACHIAL PLEXUS Pronator quadratus muscle Medial and Lateral Cords Palmar cutaneous branch Median Nerve (C[5]6-T1): In anterior forearm, of median nerve under lacertus fibrosus* (biceps aponeurosis), between the 2 heads of pronator teres.* The AIN (anterior interosseous nerve) branches, then nerve passes under arch of FDS*, then on/between FDP and FPL into carpal tunnel*. Palmar cutaneous branch divides 5cm proxi- mal to wrist & runs b/w the FCR and PL. The motor recurrent branch divides after (50%), under (30%), or through (20%) the transverse carpal ligament (TCL). Sensory: None (in forearm, see Hand) Motor: • Anterior compartment ‫ ؠ‬Pronator teres (PT) ‫ ؠ‬Flexor carpi radialis (FCR) ‫ ؠ‬Palmaris longus (PL) ‫ ؠ‬Flexor dig. super. (FDS) Anterior Interosseous Nerve (AIN): Branches proximally, then runs along the interosseous membrane with anterior interosseous artery, between FPL & FDP Sensory: Volar wrist capsule Motor: • Anterior compartment—deep flexors ‫ ؠ‬Flexor digitorum profundus (FDP) to 2nd (3rd) digits ‫ ؠ‬Flexor pollicis longus (FPL) ‫ ؠ‬Pronator quadratus (PQ) *Potential site of nerve compression. 170 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

NERVES • Forearm 5 Radial nerve (C5, 6, 7, 8, [T1]) Inconstant contribution Superficial (terminal) branch Deep (terminal) branch (PIN) Posterior view Lateral epicondyle Anconeus muscle Brachioradialis muscle Extensor carpi radialis longus muscle Supinator muscle Extensor carpi radialis brevis muscle Posterior cutaneous Extensor carpi ulnaris muscle nerve of forearm Extensor digitorum muscle and extensor digiti minimi muscle Extensor indicis muscle Extensor pollicis longus muscle Abductor pollicis longus muscle Extensor pollicis brevis muscle Superficial branch of radial nerve and dorsal Posterior interosseous nerve digital branches (continuation of deep branch of radial nerve distal to supinator muscle) Superficial (sensory) branch of radial nerve Cutaneous innervation from radial and axillary nerves BRACHIAL PLEXUS Posterior Cord Radial (C5-T1): Enters forearm b/w brachioradialis (BR) & brachialis, then divides into deep and superficial branches. Superficial br. runs under BR to thumb web space. It can be compressed under the BR tendon.* It is lateral to the radial ar- tery. Deep br. pierces the supinator, then becomes the PIN. Sensory: Posterior forearm: via posterior cutaneous nerve of forearm Motor: Anconeus • Mobile wad ‫ ؠ‬Brachioradialis (BR) ‫ ؠ‬Extensor carpi radialis longus (ECRL) Posterior Interrosseous Nerve (PIN): Runs past vascular Leash of Henry* (recurrent radial artery) and ECRB, through the arcade of Frohse* (proximal supinator), into the supinator, past its distal edge,* then along interosseous membrane under EDC and between APL and EPL. Sensory: Dorsal wrist capsule (in 4th dorsal compartment) Motor: • Mobile wad ‫ ؠ‬Extensor carpi radialis brevis (ECRB) • Posterior compartment—superficial extensors ‫ ؠ‬Supinator ‫ ؠ‬Extensor digitorum communis (EDC) ‫ ؠ‬Extensor digiti minimi (EDM or EDQ) ‫ ؠ‬Extensor carpi ulnaris (ECU) • Posterior compartment—deep extensors ‫ ؠ‬Abductor pollicis longus (APL) ‫ ؠ‬Extensor pollicis brevis (EPB) ‫ ؠ‬Extensor pollicis longus (EPL) ‫ ؠ‬Extensor indicis proprius (EIP) *Potential site of nerve compression. NETTER’S CONCISE ORTHOPAEDIC ANATOMY 171

5 Forearm • NERVES Anterior view Posterior view Ulnar nerve ([C7], 8, T1)(no Radial nerve branches above elbow) Posterior cutaneous nerve of forearm Inconstant contribution (C[5], 6, 7, 8) Medial Articular branch Medial epicondyle cutaneous (behind condyle) nerve of Flexor digitorum forearm profundus muscle (C8, T1) (medial part only; lateral part supplied Lateral cutaneous nerve of by anterior inter- forearm (C5, 6, [7]) (terminal part osseous branch of of musculocutaneous nerve) median nerve) Cutaneous Flexor carpi ulnaris innervation muscle (drawn aside) (via lateral cutaneous Dorsal cutaneous branch nerve of of ulnar nerve forearm) Palmar cutaneous branch Superficial (sensory) branch Deep (motor) branch Anterior (palmar) view Posterior (dorsal) view BRACHIAL PLEXUS Lateral Cord Musculocutaneous (C5-7): Exits between biceps & brachialis, purely sensory, runs in subcutaneous tissues above the brachioradialis Sensory: Radial forearm: via lateral cutaneous nerve of forearm Motor: None (in forearm) MEDIAL CORD Medial Cutaneous Nerve of Forearm (Antebrachial Cutaneous) (C8-T1): Branches directly from the cord, runs subcu- taneously anterior to medial epicondyle into the medial forearm Sensory: Medial forearm Motor: None Ulnar (C[7]8-T1): Runs posterior to medial epicondyle in cubital tunnel,* then through FCU heads/aponeurosis,* then runs on FDP (under FDS) to wrist. The dorsal and palmar cutaneous branches divide 4-5cm proximal to wrist, then the nerve runs into the ulnar tunnel (Guyon’s canal*), where it divides into deep/motor & superficial/sensory branches Sensory: None (in forearm) Motor: • Anterior compartment ‫ ؠ‬Flexor carpi ulnaris (FCU) ‫ ؠ‬Flexor digitorum profundus (FDP) to (3rd), 4th, 5th digits *Potential site of nerve compression. 172 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

ARTERIES • Forearm 5 Brachial artery Radial artery and Ulnar artery and Bicipital aponeurosis palmar carpal branch palmar carpal Supinator muscle branch Superficial palmar branch of radial artery Palmar carpal Brachioradialis Superficial palmar arterial arch muscle Radial artery branch of ulnar artery Pisiform Pronator teres Deep palmar Median nerve muscle (partially cut) Humeral (arterial) arch Guyon’s canal Flexor pollicis head Pronator Abductor digiti (cut) teres minimi muscle (cut) Ulnar muscle Anterior (palmar) view Deep palmar branch of ulnar head artery and deep branch of Flexor digitorum profundus muscle longus muscle Flexor carpi ulnar nerve Flexor carpi ulnaris muscle Ulna Radius radialis Ulnar artery tendon (cut) and nerve Abductor Radial artery digiti Deep palmar minimi Dorsal branch of ulnar scaphoid branch artery and deep with muscle Abductor pollicis branch of Posterior (dorsal) view brevis muscle ulnar nerve C.A. Luce COURSE BRANCHES FOREARM Radial Artery Runs over the pronator teres, on Radial recurrent (leash of Henry) FDS & FPL lateral to the FCR Muscular branches Ulnar Artery Runs under the ulnar head of the Anterior ulnar recurrent pronator teres, on the FDP mus- cle, lateral and adjacent to the Posterior ulnar recurrent ulnar nerve Common interosseous ‫ ؠ‬Anterior interosseous ‫ ؠ‬Posterior interosseous ‫ ؠ‬Recurrent interosseous Muscular branches WRIST Radial Artery Lateral to FCR tendon, wraps dor- Palmar carpal branch Deep to flexor tendons sally, under the APL & EPB ten- Dorsal carpal branch Deep to extensor tendons dons, between the 2 heads of 1st Superficial palmar branch Anastomoses w/super. palmar arch dorsal interosseous muscles, to Supplies 25% of scaphoid (distal) the palm ending in deep arch ‫ ؠ‬Palmar scaphoid branch Supplies 75% of scaphoid (proximal) Dorsal scaphoid branch Terminal branch of radial artery in hand Deep palmar arch Ulnar Artery On transverse carpal ligament (TCL) Palmar carpal branch Deep to flexor tendons into Guyon’s canal, divides into Dorsal carpal branch Deep to extensor tendons deep and superficial palmar Deep palmar branch Anastomoses with deep palmar arch branches Superficial palmar arch Terminal branch of the ulnar artery • Allen test: Occlude both radial and ulnar arteries at the wrist. Patient squeezes fist to exsanguinate the hand. Release one artery and check for hand perfusion. Repeat with the other artery. Test confirms patency of arches/vessels. NETTER’S CONCISE ORTHOPAEDIC ANATOMY 173

5 Forearm • DISORDERS Superficial branch of radial nerve Ulnar styloid TFCC tear Lunate fossa Extensor pollicis longus, Extensor extensor pollicis brevis, retinaculum abductor pollicis longus tendons Triangular fibrocartilage (disc) Course of abductor pollicis longus and extensor pollicis brevis tendons through 1st compartment of extensor retinaculum Ganglion of Wrist Extensor tendon retracted Carpal ligament and capsules Excision of ganglion via transverse incision TFCC tear Triangular fibrocartilage tear (TFCC) DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT TRIANGULAR FIBROCARTILAGE COMPLEX (TFCC) TEAR 1. Class 1: repair or de- bride tear (fix styloid • Can be traumatic (class 1) or Hx: Ulnar wrist pain, ϩ/Ϫ XR: Usually normal; tears fracture if needed) degenerative (class 2) popping/grinding assoc. w/styloid base fx PE: TFC is TTP, ϩ TFCC, MRA: Study of choice for 2. Class 2: NSAIDs, • Only periphery is vascular grind, ϩ/Ϫ piano key diagnosis of tears splint; ulnar shortening (i.e., peripheral tear can be procedure repaired) 1. Splint and NSAIDs de QUERVAIN’S TENOSYNOVITIS 2. Corticosteroid injection • Inflammation of first dorsal Hx: Radial pain/swelling XR: Usually normal into sheath compartment (APL/EPB PE: Tenderness at 1st MR: No indication 3. Surgical release tendons) dorsal compartment, ϩ Finkelstein’s test 1. Observation if asymp- • Middle age women #1. tomatic • Assoc. w/tendon abnormality GANGLION CYST 2. Aspiration (recurrence • Synovial fluid–filled cyst aris- Hx: Mass, ϩ/Ϫ pain XR: Wrist series usually 20%) ing from a wrist joint PE: Palpable, mobile normal mass, ϩ/Ϫ tenderness, MR: Will show cyst well, 3. Excision (including • Most common mass in wrist needed only if diagnosis stalk of cyst; recur- • Dorsal wrist most common ϩ transillumination is uncertain rence Ͻ10%) site (usually from SL joint) 174 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

DISORDERS • Forearm 5 Median nerve Pronator syndrome Compression by flexor digitorum superficialis Supracondylar Flexion of middle muscle process finger against resistance Compression by Ligament of Anterior pronator teres muscle Struthers interosseous n. Medial Carpal Pronation epicondyle tunnel against resistance Lacertus Compression fibrosus by lacertus fibrosus Pronator teres m. Humeral head Ulnar head Flexor digitorum superficialis m. and arch Flexor pollicis longus m. Anterior interosseous syndrome Flexion of wrist against resistance Normal Abnormal Carpal tunnel syndrome Median nerve Incision Transverse site carpal ligament Hand posture in anterior interosseous syn- drome due to paresis of flexor digitorum profundus and flexor pollicis longus muscles Decompressed carpal tunnel Compressed median nerve DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT • Proximal median nerve MEDIAN NERVE COMPRESSION 1. Activity modification/ compression rest Pronator Syndrome • Sites: 1. Ligament of 2. Splinting, NSAIDs Struthers, 2. Pronator Hx: Numbness, tingling, XR: Look for supracondylar 3. Surgical decompres- teres, 3. Lacertus fibrosis, ϩ/Ϫ weakness process off humerus 4. FDS aponeurosis/arch PE: Decreased palm sen- EMG/NCS: Can confirm sion of all proximal sation, ϩ pronator or FDS dx (can also be normal) compression sites • Rare nerve compression sign • Same sites at pronator 1. Activity modification AIN Syndrome 2. Splinting, NSAIDs syndrome 3. Surgical decompres- • Motor symptoms only Hx: Weakness, ϩ/Ϫ pain XR: Usually normal PE: Weak thumb (FPL) and EMG/NCS: Will confirm sion • Compression in carpal IF (FDP) pinch diagnosis if unclear tunnel 1. Activity modification Carpal Tunnel Syndrome 2. Night splints, NSAIDs • Most common neuropathy 3. Corticosteroid injection • Associated with metabolic Hx: Numbness, ϩ/Ϫ pain XR: Usually normal 4. Carpal tunnel release PE: ϩ/Ϫ thenar atrophy, EMG/NCS: Will confirm diseases (thyroid, diabe- ϩ Durkin’s, ϩ/Ϫ Phalen’s, diagnosis if unclear (incr. tes), pregnancy & Tinel’s tests latency, decr. velocity) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 175

5 Forearm • DISORDERS Radial n. Radial Nerve Compression Motor signs Recurrent Sensory signs in radial tunnel syndrome Posterior interosseous radial a. syndrome Pain and Pain Paresthesia and Posterior tenderness radiation hypesthesias Loss of wrist and interosseous n. finger extension Extensor carpi radialis brevis m. Provocative tests for radial tunnel syndrome Supinator m. Superficial radial n. Vascular Supination against resistance leash of Henry Fibrous arcade of Frohse Posterior interosseous n. Innervation of Superficial extensor mm. Tendon of radial n. at wrist brachioradialis m. DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT • Compression in radial tunnel RADIAL NERVE COMPRESSION 1. Activity modification • Sites: 1. Fibrous bands, 2. Splint, NSAIDs PIN Syndrome 3. Surgical decompression 2. Leash of Henry, 3. ECRB, 4. Arcade of Frohse (proximal Hx: Hand & wrist XR: Look for radiocapitellar (complete release) supinator edge), 5. Distal edge weakness, ϩ/Ϫ abnormality of supinator elbow pain MR: Evaluate for masses 1. Activity modification PE: Weak thumb/ EMG/NCS: Confirms diagno- 2. Splint, NSAIDs • Compression in radial tunnel finger ext., TTP at sis & localizes lesion 3. Surgical decompression • Same sites as above radial tunnel • Pain only, no weakness 1. Activity modification Radial Tunnel Syndrome 2. Wrist splint, NSAIDs • Compression of superficial 3. Surgical decompression radial nerve at wrist (b/w ERCL Hx: Lat. elbow pain XR: Evaluate RC joint and BR tendons) PE: Radial tunnel MR: Evaluate for masses 1. Activity modification TTP, no weakness EMG/NCS: Not useful 2. Splint, NSAIDs • Sensory symptoms only 3. Surgical decompression Wartenberg’s Syndrome • Compression in Guyon’s canal (address underlying • Etiology: ganglion, hamate mal- Hx: Numbness/pain XR: Usually normal cause of compression) PE: Decr. sensation MR: Usually not helpful union, thrombotic a., muscle IF/thumb. ϩ Tinel’s, EMG/NCS: May confirm • Sensory (zone 3), motor (zone diagnosis sx w/pronation 2), or mixed (zone 1) symptoms ULNAR NERVE COMPRESSION Ulnar Tunnel (Guyon’s Canal) Syndrome Hx: Numbness, XR: Look for fracture weakness in hand CT: Evaluate for fx/malunion PE: Decr. sensation, MR: Useful for masses ϩ/Ϫ atrophy, claw- US: Evaluate for thrombosis ing, weakness EMG: Confirm diagnosis 176 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Volar carpal ligament Ulnar tunnel syndrome DISORDERS • Forearm 5 Palmaris Transverse carpal Ulnar nerve brevis m. ligament Ulnar tunnel Pisiform Ulnar n. Ulnar a. Zone I (motor Zones of nerve compression and clinical signs and sensory) Zone II Deep (motor) (motor) branch of Sensory findings occur with compression in zones I and III ulnar n. Clawing of 4th and Zone III Superficial 5th fingers (sensory) (sensory) branch of Interosseous ulnar n. atrophy Motor findings with compression in zones I and II DESCRIPTION EVALUATION TREATMENT CARPAL INSTABILITY Acute/early treatment: 1. Fx: ORIF of scaphoid Carpal Instability, Dissociative (CID) 2. Ligament: SL or LT liga- Instability within a carpal row; two main types: Hx: Trauma, pain ϩ/Ϫ popping ment repair or reconstruc- PE: ϩ/Ϫ decreased ROM, ϩ/Ϫ tion with pin fixation 1. Dorsal intercalated segment instability (DISI) 3. Capsulodesis ‫ ؠ‬Due to scapholunate (SL) ligament disruption or snuffbox or SL/LT interval ten- Chronic/late treatment: scaphoid fracture/nonunion 1. Limited fusion (e.g., STT ‫ ؠ‬Deformity: scaphoid flexes, lunate extends derness, ϩ Watson test (DISI) fusion for DISI) ‫ ؠ‬May lead to STT arthritis or SLAC wrist or Regan test (VISI) 1. Nonoperative: splint/cast 2. Volar intercalated segment instability (VISI) XR: Wrist & clenched fist views (esp. midcarpal) ‫ ؠ‬Due to lunotriquetral ligament disrupted (also ‫ ؠ‬DISI: SL gap Ͼ3mm, SL requires dorsal radiocarpal lig. injury) angle Ͼ70º, “ring sign” 2. Arthrodesis (fusion) ‫ ؠ‬VISI: disrupted carpal ‫ ؠ‬Midcarpal arches ‫ ؠ‬Radiocarpal MRA: Can confirm ligament inj. 1. ORIF of bones with primary repair of ligaments Carpal Instability, Nondissociative (CIND) 2. Late: arthrodesis • Instability between carpal rows Hx: Fall/trauma or ligament hy- • Midcarpal or radiocarpal variations perlaxity; popping/clunking • Associated with generalized hyperlaxity or trauma PE: Tenderness, instability XR: Evaluate for fxs & static to ligaments (e.g., ulnar translation at RCJ) or to carpal translation bones (e.g., distal radius fracture) Fluoro: Dynamic carpal transl. Carpal Instability, Combined (CIC) • Instability both within a row & between rows Hx: Fall/trauma, pain • Perilunate dislocation most common PE: Tenderness, instability • Greater arc injury = transosseous injury XR: Disruption of carpal arches, • Lesser arc injury = ligamentous injury lunate abnormality (angle &/or position) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 177

5 Forearm • DISORDERS Kienböck’s Disease Rheumatoid Arthritis Radiograph shows cartilage thinning at proximal Radiograph of wrist shows characteristic interphalangeal joints, erosion of carpus and sclerosis of lunate wrist joint, osteoporosis, and finger deformities DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT DEGENERATIVE/ARTHRITIC CONDITIONS • Primary osteoarthritis in the wrist is uncommon. It is usually posttraumatic (distal radius/scaphoid fx or lig. injury). Scapholunate Advanced Collapse (SLAC) • Wrist arthritis due to Hx: Prior trauma/fall (often XR: 4 stages. DJD at: I. Styloidectomy & STT posttraumatic scaphoid untreated), pain I. Rad. styloid & scaphoid fusion flexion deformity (SL liga- PE: ϩ/Ϫ decreased ROM II. Radioscaphoid joint ment injury or scaphoid with pain, tenderness to III. Capitolunate joint II. Proximal row carpectomy fracture [SNAC]) palpation IV. Capitate migration or scaphoidectomy & (radiolunate joint is 4 corner (lun., tri., cap., • Arthritis progresses over spared) ham.) fusion four stages (I-IV) III. 4 corner fusion IV. Wrist arthrodesis (fusion) Rheumatoid Arthritis • Inflammatory disorder at- Hx: Pain (esp. in AM), stiff- XR: Wrist series. Depends 1. Medical management tacks synovium and de- ness, deformity on severity. Mild degen- 2. Synovectomy stroys joint PE: Swelling, deformity (vo- eration to destruction of 3. Tendon transfers lar, ulnar translation of the joint. 4. Wrist fusion or arthro- • Radiocarpal (supination carpus) LABS: RF, ANA, ESR &, ulnar volar translation) plasty & DRUJ (ulna subluxates dorsally) affected Kienböck’s Disease • Osteonecrosis of the Hx: Pain, stiffness, and dis- XR: Stage I: Normal x-ray; Stage: lunate ability of wrist II: Lunate sclerosis I: Immobilization PE: Lunate/proximal row IIIA: Lunate fragmented I-IIIA: Radial shortening • Etiology: traumatic or re- tenderness, decreased IIIB: IIIA ϩ scaphoid IIIB: STT fusion or proximal petitive microtrauma to ROM, decreased grip flexed lunate strength IV. DJD of adjacent joints row carpectomy (PRC) IV: Wrist fusion or PRC • 4 radiographic stages MR: Needed to dx stage I • Associated with ulnar negative variance of wrist 178 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

PEDIATRIC DISORDERS • Forearm 5 Madelung’s Deformity Dorsal view of hand Prominence of ulnar Radiograph shows ulnar inclination of Lateral radiograph reveals prominence demonstrates dorsal of ulnar heads head, palmar deviation articular surfaces of distal radius, wedging prominence of ulnar head with palmar of hand, and bowing of of carpal bones into resulting space, and deviation of carpal bones forearm clearly seen on bowing of radius radial view Radial Club Hand Osteology of ulna Kirschner wire Short, bowed forearm with marked Centralization radial deviation of hand. Thumb absent. procedure Radiograph shows partial deficit of radial ray (vestige of radius present). Scaphoid, trapezium, and metacarpal and phlanges of thumb absent. DESCRIPTION EVALUATION TREATMENT MADELUNG’S DEFORMITY • Deformity of the distal radius Hx: Pain in wrists & deformity Asymptomatic: observation and/or • Volar ulnar physis disrupted causes PE: Deformity & prominent ulna head activity modification XR: Distal radius deformity (incr. tilt & Symptomatic: radial osteotomy ϩ/Ϫ increased volar tilt & radial inclination) & dorsal ulna sublux- ulna recession inclination ation • Ages 6-12; femalesϾmales RADIAL CLUB HAND (RADIAL HEMIMELIA) • Failure of formation (partial or com- Hx/PE: Bowing of forearm, radial de- 1. Elbow ROM (no surgery if stiff) plete: stages I-IV) of the radius viation of hand 2. Hand centralization (age 1) XR: Radius short or absent, bowed • Associated with syndromes (TAR, ulna VATER) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 179

5 Forearm • SURGICAL APPROACHES Posterior Approach to Forearm Supinator Brachialis Incision site with Superficial Brachioradialis arm in supination branch of radial Radius nerve Ulna Periosteum Biceps brachii Ulna (opened) Biceps aponeurosis Biceps tendon Flexor carpi radialis Pronator teres Radial artery Pronator teres Brachioradialis Supinator Flexor carpi radialis Flexor pollicis Flexor Superficial longus digitorum radial nerve sublimis Radius Radius Deep dissection done Ulna with forearm in pronation Forearm in pronation USES INTERNERVOUS PLANE DANGERS COMMENT • ORIF of fractures FOREARM: ANTERIOR APPROACH (HENRY) • Most commonly only a • Osteotomy portion of the incision is • Biopsy & bone Proximal • Radial artery needed/used ‫ ؠ‬Brachioradialis (radial) • Superficial radial nerve tumors ‫ ؠ‬Pronator teres (median) • Posterior interosseous • Proximally, must ligate the radial recurrent artery • ORIF of fractures Distal nerve (PIN) • Wrist fusion or car- ‫ ؠ‬Brachioradialis (radial) • Distally, must detach prona- ‫ ؠ‬FCR (median) tor quadratus to get to dis- pectomy tal radius • Tendon repair WRIST: DORSAL APPROACH • If needed, a compartment • ORIF (e.g., distal ra- • No internervous plane • Superficial radial nerve other than the 4th can be dius, scaphoid) (muscles all innervated by • Radial artery opened radial nerve [PIN]) • Carpal tunnel re- • The capsular sensory lease • 4th dorsal compartment is branch of the PIN is in the opened & tendons are 4th compartment • Tendon repair retracted • Incise transverse carpal lig- WRIST: VOLAR APPROACH ament to access volar wrist capsule/bones Proximal (same as Henry) • Median nerve ‫ ؠ‬Brachioradialis (radial) ‫ ؠ‬Palmar cutaneous br. • Must detach pronator ‫ ؠ‬FCR (median) ‫ ؠ‬Motor recurrent branch quadratus to expose distal radius Distal (over wrist & palm) • Superficial palmar arch ‫ ؠ‬None 180 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

SURGICAL APPROACHES • Forearm 5 Dorsal Approach to Wrist Joint Incision Extensor tendons site (retracted) Radius Ulna Radius Ulna Hamate Scaphoid Trapezium Capitate Volar Approach to Wrist Joint Incision Flexor tendons (retracted) site Median nerve Pisiform Triquetrum Scaphoid Lunate Flexor tendons Pronator quadratus Volar Transverse capsule carpal ligament (opened) (divided) Lunate Radius Scaphoid Capitate NETTER’S CONCISE ORTHOPAEDIC ANATOMY 181

5 Forearm • SURGICAL APPROACHES Midcarpal radial Midcarpal ulnar 1-2 6R 3-4 6U 4-5 Distal radioulnar PORTAL LOCATION DANGERS COMMENT WRIST ARTHROSCOPY PORTALS • Uses: Diagnostic, TFCC tears, synovectomy, assist in fracture fixation, loose body removal, chondral lesions • Portals are named for relation to the dorsal extensor wrist compartments (R & U indicate radial or ulnar side of tendon). 1-2 Between APL & ECRL 1. Deep branch of radial art. • Use is limited b/c of close proximity to tendons. Distal to ra- 2. Superficial radial n. brs. & risk of neurovascular injury dial styloid 3. Lat. antebrachial cut. brs. • Shows distal scaphoid & radial styloid 3-4 Between EPL & EDC None (PIN capsular br. in 4th • The “workhorse” portal of arthroscopy tendons, 1cm distal to comp) • Shows SL interosseous lig., ligament of Lister’s tubercle Testut (RSL), distal radius fossae 4-5 Between EDC & EDQ None • Shows radial TFCC attachment, LT interos- tendons seous ligament 6R Radial side of ECU ten- Dorsal cutaneous br. ulnar n. • Shows ulnar insertion of TFCC, UT, & UL don (b/w EDQ & ECU) ligaments, prestyloid recess 6U Ulnar side of ECU Dorsal cutaneous br. ulnar n. • Similar to 6R. Used less due to risk of tendon nerve injury. Can be used for outflow. Midcarpal 1cm distal to 3-4 por- None • Distal scaphoid, proximal capitate, SL liga- radial tal, along radial border ment, STT articulation of 3rd MC Midcarpal 1cm distal to 4-5 por- None • Lunotriquetral joint, LT ligament, triquetro- ulnar tal, in line with 4th MC hamate articulation Other portals: Midcarpal: STT and triquetrohamate. Distal radioulnar: proximal and distal to ulnar head. FASCIOTOMIES See page 169. 182 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Topographic Anatomy CHAPTER 6 Osteology Radiology Hand Trauma Tendons 184 Joints 185 Other Structures 186 Minor Procedures 187 History 190 Physical Exam 192 Origins and Insertions 196 Muscles 199 Nerves 200 Arteries 201 Disorders 206 Pediatric Disorders 207 Surgical Approaches 210 212 213 216 218

6 Hand • TOPOGRAPHIC ANATOMY Common names Anterior view of digits 1 Thumb 2 Index 3 Middle 4 Ring 5 Little Flexor carpi radialis tendon Thenar eminence Palmaris longus tendon Radial longitudinal crease Posterior view Distal 1 Flexor digitorum palmar superficialis tendons crease Flexor carpi ulnaris tendon Hypothenar eminence 2 Proximal palmar crease 3 Proximal digital crease Middle digital crease Site of 4 5 Distal digital crease metacarpophalangeal joint Extensor pollicis Anatomic longus tendon snuff box Site of thumb 1 carpometacarpal joint Extensor indicis Ulnar styloid tendon 2 Extensor digitorum tendons Site of Site of proximal metacarpophalangeal interphalangeal (PIP) joint joint 3 Site of distal 45 interphalangeal (DIP) joint STRUCTURE CLINICAL APPLICATION Palmaris longus tendon Not present in all people. Can be used for tendon grafts. Anatomic snuffbox Site of scaphoid. Tenderness can indicate a scaphoid fracture. Thumb carpometacarpal joint Common site of arthritis and source of radial hand pain. Thenar eminence Atrophy can indicate median nerve compression (e.g., carpal tunnel syndrome). Hypothenar eminence Atrophy can indicate ulnar nerve compression (e.g., ulnar or cubital tunnel syndrome). Proximal palmar crease Approximate location of the superficial palmar arch of the palm. Distal palmar crease Site of metacarpophalangeal joints on volar side of hand. 184 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

OSTEOLOGY • Hand 6 Scaphoid Lunate Triquetrum Carpal and Pisiform bones Tubercle Carpal Capitate bones Trapezium Hamate and Hook and Tubercle 1 Trapezoid Sesamoid 2 Base Right hand: bones 34 Shafts Metacarpal bones anterior (palmar) view 5 Head Base Shafts Proximal phalanges Head Base Shafts Middle phalanges Head Base Distal Shafts phalanges Tuberosity Head Lunate Carpal Scaphoid bones Capitate Trapezoid Pisiform Trapezium Triquetrum Carpal bones Hamate Metacarpal bones Base 5 43 1 Shafts 2 Head Proximal phalanges Base Shafts Right hand: Head posterior (dorsal) view Base Middle phalanges Shafts Head Base Distal Shafts phalanges Tuberosity Head CHARACTERISTICS OSSIFY FUSE COMMENT METACARPALS • Triangular in cross section: gives Primary: body 9wk 18yr • Named I-V (thumb to small 2 volar muscular attachment sites (fetal) finger) Secondary 2yr 18yr • Thumb MC has saddle-shaped base: epiphysis • Only one physis per bone in the increases it mobility head; base in thumb MC PHALANGES • Volar surface is almost flat Primary: body 8wk 14-18yr • 3 in each digit except thumb (fetal) (two) • Tubercles and ridges are sites for Secondary 2-3yr 14-18yr attachment epiphysis • Only one physis per bone; it is in the base • Nomenclature for digits: thumb, index finger (IF), middle finger (MF), ring finger (RF), small/little finger (SF or LF), proxi- mal phalanx (P1), middle phalanx (P2), distal phalanx (P3) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 185

6 Hand • RADIOLOGY X-ray, hand Lateral x-ray, finger X-ray, finger Distal Distal Middle finger Ring interphalangeal phalanx finger joint (DIP) (P3) Small Proximal Tuft finger interphalangeal joint (PIP) Middle phalanx Index finger Metacarpo- (P2) phalangeal joint Proximal phalanx Thumb (P1) Distal interphalangeal joint (IP) interphalangeal joint (DIP) CMC Proximal interphalangeal joint (PIP) X-ray, hand Sesamoid Distal Distal bone interphalangeal phalanx joint (DIP) (P3) Middle Proximal phalanx interphalangeal (P2) joint (PIP) Proximal Metacarpal phalanx neck (P1) Metacarpal base RADIOGRAPH TECHNIQUE FINDINGS CLINICAL APPLICATION AP (anteroposterior) Palm down on plate, beam Metacarpals, phalanges, Hand & finger fractures, hand Lateral Oblique perpendicular to plate CMC, MCP, and IP joints joint dislocations and DJD Thumb stress view Ulnar wrist and hand on plate, Alignment of bones, joints Same as above CT stagger finger flexion Alignment and position of Same as above MRI Lateral with 40° rotation bones Bone scan Thumb MCPJ under stress Evaluate ulnar collateral liga- Abduct thumb at 0° & 30° of ment integrity (gamekeeper’s flexion, beam at MCPJ thumb) OTHER STUDIES Fractures (esp. scaphoid, hook of hamate), nonunions Axial, coronal, and sagittal Articular congruity, bone Occult fractures (e.g., scaph- healing, bone alignment oid), ligament/tendon injuries Infection, stress fxs, tumors Sequence protocols vary Soft tissues (ligaments, tendons), bones All bones evaluated 186 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

TRAUMA • Hand 6 Metacarpal Fractures Transverse fractures of metacarpal shaft usually angulated dorsally by pull of interosseous muscles In fractures of metacarpal neck, volar cortex often Oblique fractures tend to shorten and comminuted, resulting in marked instability after rotate metacarpal, particularly in index reduction, which often necessitates pinning and little fingers because metacarpals of middle and ring fingers are stabilized by deep transverse metacarpal ligaments Fracture of Base of Metacarpals of Thumb 1st metacarpal Bone fragment Trapezium Abductor pollicis longus tendon Type I (Bennett fracture). Intraarticular fracture Type II (Rolando fracture). with proximal and radial dislocation of 1st meta- Intraarticular fracture with carpal. Triangular bone fragment sheared off Y-shaped configuration Fracture of Proximal Phalanx Reduction of fractures of phalanges or metacarpals requires correct rotational as well as longitudinal alignment. In normal hand, tips of flexed fingers point toward tuberosity of scaphoid, as in hand at left. DESCRIPTION EVALUATION CLASSIFICATION TREATMENT METACARPAL FRACTURES • Common in adults, usually a fall Hx: Trauma, pain, swell- By location: • Nondisplaced: cast or punching mechanism ing,ϩ/Ϫ deformity PE: Swelling, tenderness. • Head • Displaced: reduce • 5th MC most common (boxer fx) Check for rotational de- ‫ ؠ‬Stable: cast • Thumb MC base fractures: dis- formity. Check neurovas- • Neck (most common) ‫ ؠ‬Unstable: CR-PCP cular integrity. vs. ORIF placed, intraarticular fractures XR: Hand. Evaluate for an- • Shaft (transverse, spiral) ‫ ؠ‬Shortened: ORIF problematic gulation & shortening ‫ ؠ‬Bennett’s fx: APL deforms fx CT: Useful to evaluate for • Base • Intraarticular ‫ ؠ‬Rolando’s fx: can lead to DJD nonunion of fracture ‫ ؠ‬Thumb MC ‫ ؠ‬Head: ORIF • 4th & 5th MCs can tolerate ‫ ؠ‬Bennett: volar lip fx ‫ ؠ‬Thumb base: some angulation, 2nd & 3rd ‫ ؠ‬Rolando: commi- ‫ ؠ‬Bennett: cannot nuted CR-PCP ‫ ؠ‬Small finger MC: ‫ ؠ‬Rolando: ORIF “Baby Bennett” COMPLICATIONS: Nonunion/malunion, grip strength deficiency, posttraumatic osteoarthritis (esp. Rolando fractures) NETTER’S CONCISE ORTHOPAEDIC ANATOMY 187

6 Hand • TRAUMA Phalangeal Fractures Extraarticular oblique shaft Intraarticular phalangeal base Intraarticular condyle fractures. (diaphysis) fracture. fracture. Intraarticular fractures Fractures of distal phalanx of phalanx that are non- displaced and stable may be treated with buddy taping, careful observation, and early active exercise. Fracture dislocation B of middle phalanx. AC D Types of fractures. A. Longitudinal B. Nondisplaced transverse C. Angulated transverse D. Comminuted Extension block splint useful for fracture dislocation of proximal DESCRIPTION EVALUATION CLASSIFICATION TREATMENT PHALANGEAL FRACTURES • Common injury Hx: Trauma, pain, Description: • Extraarticular: • Mechanism: jamming, crush, swelling, ϩ/Ϫ deformity • Intra- vs extraarticular ‫ ؠ‬Stable: buddy tape/ • Displaced/ splint or twisting PE: Swelling, tenderness. ‫ ؠ‬Unstable: CR-PCP vs • Distal phalanx most common Check for rotational de- nondisplaced ORIF • Stiffness is common prob- formity. Check neurovas- • Transverse, spiral, cular integrity. • Intraarticular: ORIF lem; early motion and occu- XR: Hand. Evaluate for oblique • Middle phalanx volar pational therapy needed for angulation & shortening Location: best results CT: Useful to evaluate for • Condyle base fx: • Intraarticular fractures can nonunion of fracture • Neck ‫ ؠ‬Stable: extension block lead to early osteoarthritis • Shaft/diaphysis • Nail bed injury common w/ • Base splint tuft (distal phalanx) fx • Tuft ‫ ؠ‬Unstable: ORIF • Tuft fx: irrigate wound, repair nail bed as needed, splint fx/digit COMPLICATIONS: Stiffness/loss of range of motion (esp. intraarticular fractures), nonunion/malunion, osteoarthritis 188 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

TRAUMA • Hand 6 Gamekeeper’s thumb Mallet finger Torn ulnar Adductor pollicis m. A. Tendon torn from A collateral and its insertion. B. Bone B ligament aponeurosis (cut) fragment avulsed with tendon. In A and B there is a 40°- 45° flexion deformity and loss of active extension Ruptured ulnar collateral ligament of metacarpopha- langeal joint of thumb Jersey finger Splinted Mallet Finger Flexor digitorum profundus tendon may be torn directly from distal phalanx or may avulse small or large bone fragment. DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT MALLET FINGER—EXTENSOR DIGITORUM AVULSION • Rupture of extensor tendon Hx: “Jammed” finger; XR: Hand series. Look for 1. DIPJ extension splint, from distal phalanx pain, DIPJ deformity bony avulsion (EDC) fx 6wk for most injuries PE: Extensor lag at DIPJ; from dorsal base of P3 • Soft tissue or bony form inability to actively ex- in bony form of injury 2. Bony mallet with DIPJ • Mech: jamming finger tend DIPJ subluxation: consider PCP vs ORIF JERSEY FINGER—FLEXOR DIGITORUM PROFUNDUS AVULSION • FDP tendon rupture from P3 Hx: Forced DIPJ exten- XR: Hand series. Look for Leddy classification: Type: • Mech: forced extension sion, injury; pain avulsion fracture from • 1: to palm. Early repair PE: Inability to flex DIPJ volar base of P3. May • 2: to PIPJ. Repair Ͻ6wk against a flexed finger (Ϫprofundus test) be retracted to finger/ • 3: bony to A4: ORIF • Tendon retracts variably palm. GAMEKEEPER’S THUMB • Thumb MCP joint proper ul- Hx: Pain, decreased grip XR: Hand; r/o avulsion fx • Incomplete tear (sprain) nar collateral ligament injury PE: Pain & laxity of Stress Fluoro: Can com- or no Stenor lesion: MCPJ at 30° of flexion, splint 4-6wk • Mech: forced radial deviation ϩ/Ϫ palpable mass pare side to side asym. • Often a ski pole injury (Stenor lesion) MR: If diagnosis is un- • Complete tear or Stenor clear lesion: primary repair • Stenor lesion: when adductor aponeurosis falls under torn ulnar collateral ligament, producing a palpable mass/bump • Stress testing of the thumb MCP in extension tests the accessory collateral ligament and volar plate integrity NETTER’S CONCISE ORTHOPAEDIC ANATOMY 189