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Home , Metacarpal bones

Hand and Bony distal and 8 carpal 5 metacarpals 14 phalanges Bony Anatomy

Distal radius- broadens to form a small ulnar notch on its medial surface - projects off the anterolateral border Bony Anatomy

Ulnar head- more circular, with the arising from the medial surface

Aligned in two rows:

Proximal row Distal row Proximal Row (lateral to medial) scaphoid- articulates proximally with the radius and has a prominent tubercle lunate- articulates proximally with the radius and is broader anteriorly than posteriorly triquetrum- articulates proximally with the articular disc of the distal radioulnar pisiform- lies on the palmar surface of the triquetrum Distal Row (lateral to medial) -4 sided trapezoid- wedge shaped capitate- rounded head hamate- wedge shaped and has a hooked process, the hook of the hamate Metacarpal Bones numbered I-V body and two ends proximal ends or bases distal ends or heads Metacarpal Bones bases of the metacarpals concave to articulate with the carpal bones heads of the metacarpals convex to articulate with the proximal phalanges Metacarpal Bones

1st metacarpal (): thickest and shortest two sesamoid bones over the distal ends

3rd metacarpal: distinguished by a styloid process on the lateral side of its base Phalanges each digit has 3 phalanges, except the thumb (2) BASE (proximally) BODY (center) HEAD (distally) Distal Radioulnar Joint formed by the ulnar head and the ulnar notch of the radius allows 1° of freedom of movement: pronation/supination Radiocarpal Joint Formed by the distal end of radius articulating with the scaphoid & lunate and the triangular disk articulating with the lunate & triquetrum

Provides 2° of freedom of movement: flexion/extension of Radiocarpal Joint

Radial collateral (RCL) origin- styloid process insertion- scaphoid & trapezium

limits ulnar deviation Ligaments of Radiocarpal Joint

Ulnar collateral ligament (UCL) origin- ulnar styloid process insertion- triquetrum dorsally & pisiform palmarly limits radial deviation Ligaments of Radiocarpal Joint Palmar (volar) radiocarpal ligament most important ligament for controlling motion and wrist stability origin- anterior surface of distal radius insertion- courses obliquely and medially to split into the radiocapitate ligament, the radiotriquetrum ligament, and the radioscaphoid ligament. Ligaments of Radiocarpal Joint Dorsal radiocarpal ligament origin- posterior surface of the distal radius & styloid process insertion- lunate & triquetrum

limits wrist flexion Intercarpal

Interconnecting the carpal bones by small palmar, dorsal, and interosseous ligaments. very little gliding occurs between the bones Midcarpal Joints The proximal and distal carpal rows are separated by a single joint cavity with small fibrous projections connecting the rows.

This structure allows limited movements… flexion/extension radial/ulnar deviation and glide Carpometacarpal Joints The first three metacarpals articulate with a single carpal: MC I- with the trapezium MC II- with the trapezoid MC III- with the capitate

4th and 5th articulate with the hamate to form one of the carpometacarpal (CMC) joints Ligaments of Carpometacarpal Joint Bones are united by anterior carpometacarpal and metacarpal ligaments as well as by the posterior and interosseous ligaments. Transverse Carpal Ligament encloses the median , FPL, FDP, and FDS on the palmer surface of the . Metacarpophalangeal & Interphalangeal Joints Metacarpophalangeal articulations are condyloid joints with movement in two planes flexion/extension & adduction/abduction

Interphalangeal articulations are hinge joints with flexion/extension only Ligaments of the MCP & IP Joints Each fibrous capsule is strengthened by …

Two collateral ligaments pass distally from the heads of the MCP and phalanges to the bases of the phalanges limits amount of abduction/adduction Ligaments of MCP & IP Joints Palmar ligament (plate) Reinforces the palmar aspect of the MCP joints

Dorsally, the MCP joints are reinforced by the extensor hood and the transverse metacarpal ligament. Limit abduction/adduction and reinforce the palmar ligaments Pronator Teres

Proximal Attachment:Medial epicondyle of & coronoid process of ulna Distal Attachment: Middle of lateral surface of radius Innervation: Median nerve (C6-C7) Main Action: Pronates & flexes (at elbow) Flexor Carpi Radialis Proximal Attachment: Medial epicondyle of humerus Distal Attachment:Base of 2nd metacarpal Innervation:Median nerve (C6-C7) Main Action:Flexes & abducts hand (at wrist) Palmaris Longus

Proximal Attachment: Medial epicondyle of humerus Distal Attachment: Distal half of flexor retinaculum & palmar aponeurosis Innervation:Median nerve (C7-C8) Main Action:Flexes hand (at wrist) & tightens palmar aponeurosis Flexor Carpis Ulnaris Proximal Attachment: Humeral head: medial epicondyle of humerus Ulnar head: & posterior border of ulna Distal Attachment:, hook of , & 5th metacarpal bone Innervation:Ulnar nerve (C7-C8) Main Action:Flexes & adducts hand (at wrist) Flexor Digitorum Superficialis Proximal Attachment: Humeroulnar head: med. epicondyle of humerus, ulnar collateral lig. & coronoid process of ulna Radial Head: superior 1/2 of ant. border of radius Distal Attachment: Bodies of middle phalanges of medial four digits Innervation: Median nerve (C7, C8,& T1) Continued Flexor Digitorum Superficialis Main Action:Flexes middle phalanges at proximal interphalangeal joints of medial 4 digits;acting more strongly, it also flexes proximal phalanges at metacarpo- phalangeal joints & hand Flexor Digitorum Profundus

Proximal Attachment: Proximal 3/4 of medial & anterior surfaces of ulna & interosseous membrane Distal Attachment: Bases of distal phalanges of medial four digits Innervation: Medial part: Ulnar nerve (C8 & T1) Lateral part: Median nerve (C8 & T1) Con’t Flexor Digitorum Profundus Main Action: Flexes distal phalanges at distal interphalangeal joints of medial four digits; assists with flexion of hand Flexor Pollicus Longus

Proximal Attachment: Ant. Surface of radius & adjacent interosseus membrane Distal Attachment: Base of distal phalanx of thumb Innervation:Anterior interosseus nerve from median (C8 & T1) Main Action:Flexes phalanges of 1st digit (thumb) MUSCLES OF THE THUMB Pronator Quadratus Proximal Attachment: Distal 4th of anterior surface of ulna Distal Attachment: Distal 4th of anterior surface of radius Innervation:Anterior interosseus nerve from median (C8 & T1) Main Action:Pronates forearm; deep fibers bind radius & ulna together Brachioradialis

Proximal Attachment: Proximal 2/3 of lateral supracondylar ridge of humerus Distal Attachment:Lateral surface of distal end of radius Innervation:Radial nerve (C5, C6,and C7) Main Action: Flexes forearm Extensor Carpi Radialis Longus Proximal Attachment: lateral suprocondylar ridge of humerus Distal Attachment:Base of 2nd metacarpal Innervation:Radial nerve (C6 & C7) Main Action:Extend & abduct hand at wrist Extensor Carpi Radialis Brevis

Proximal Attachment: lateral epicondyle of humerus Distal Attachment:Base of 3rd metacarpal Innervation:Deep branch of radial nerve (C7 & C8) Main Action:Extend & abduct hand at wrist Extensor Digitorum Proximal Attachment: lateral epicondyle of humerus Distal Attachment: of medial 4 digits Innervation:Posterior interosseous nerve(C7& C8), the continuation of deep branch of radial nerve Main Action:Extends medial 4 digits at metacarpophalangeal joints; extends hand at wrist joint EXTENSOR DIGITORUM Extensor Digiti Minimi Proximal Attachment:lateral epicondyle of humerus Distal Attachment:Extensor expansion of 5th digit Innervation:Posterior interosseous nerve (C7& C8), the continuation of deep branch of radial nerve Main Action:Extends 5th digit at metacarpo-phalangeal & interphalangeal joints Extensor Carpi Ulnaris Proximal Attachment: lateral epicondyle of humerus and posterior border of ulna Distal Attachment:Base of 5th metacarpal Innervation:Posterior interosseous nerve(C7& C8), the continuation of deep branch of radial nerve Main Action:Extends and adducts hand at wrist joint Supinator Proximal Attachment: Lateral epicondyle of humerus, radial collateral & anular ligaments, supinator fossa, & crest of ulna Distal Attachment:Lateral, posterior, & anterior surfacesof proximal 1/3 of radius Innervation:Deep branch of radial nerve (C5 & C6) Main Action:Supinates forearm (rotates radius to turn palm anteriorly) Abductor Pollicus Longus Proximal Attachment: Posterior surfaces of ulna, radius, &interosseus membrane Distal Attachment:Base of 1st metacarpal Innervation:Posterior interosseous nerve (C7 & C8) the continuation of Deep branch of radial Main Action:Abducts thumb & extends it at carpometacarpal joint Extensor Pollicus Brevis Proximal Attachment: Posterior surface of radius & interosseous membrane Distal Attachment:Base of proximal phalanx of thumb Innervation:Posterior interosseous nerve (C7 & C8) the continuation of Deep branch of radial Main Action:Extends proximal phalanx of thumb at carpometacarpal joint Extensor Digitorum Longus Extensor Pollicus Longus Proximal Attachment: Posterior surface of middle 1/3 of ulna & interosseous membrane Distal Attachment:Base of distal phalanx of thumb Innervation:Posterior interosseous nerve (C7 & C8) the continuation of Deep branch of radial Main Action:Extends distal phalanx of thumb at metacarpophalangeal & interphalangeal joints Extensor Indicis Proximal Attachment: Posterior surface of ulna & interosseus membrane Distal Attachment:Extensor expansion of 2nd digit Innervation:Post. interosseous nerve (C7 & C8)the continuation of deep branch of radial Main Action:Extends 2nd digit & help to extend hand THENAR MUSCLES

Abductor Pollicus Brevis Flexor Pollicus Brevis Opponens Pollicis Abductor Pollicus Brevis

Proximal Attachment: Flexor retinaculum & tubercles of scaphoid & trapezium Distal Attachment:Lateral side of base of proximal phalanx of thumb Innervation:Recurrent branch of median nerve (C8&T1) Main Action:Abd. Thumb & helps oppose it Flexor Pollicus Brevis

Proximal Attachment: Flexor retinaculum & tubercles of scaphoid & trapezium Distal Attachment:Lateral side of base of proximal phalanx of thumb Innervation:Recurrent branch of median nerve (C8&T1) Main Action:Flexes thumb Opponens Pollicis Proximal Attachment: Flexor retinaculum & tubercles of scaphoid & trapezium Distal Attachment:Lateral side of 1st metacarpal Innervation:Recurrent branch of median nerve (C8 &T1) Main Action:Draws 1st metacarpal bone laterally to oppose thumb toward center of palm & rotates it medially Adductor Pollicus

Proximal Attachment: Oblique head: bases of 2-3 metacarpals, capitate, & adjacent carpals Transverse head: anteroir surface of body of 3rd metacarpal Distal Attachment:Medial side of base of proximal phalanx of thumb Innervation:Deep branch of ulnar (C8 & T1) Main Action:Adducts thumb toward middle digit ADDUCTOR POLLICUS HYPOTHENAR MUSCLES

Abductor digiti minimi Flexor digiti minimi brevis Opponens digiti minimi Abductor Digiti Minimi

Proximal Attachment: Pisiform Distal Attachment:Medial side of base of proximal phalanx of little finger Innervation:Deep branch of ulnar (C8 & T1) Main Action: Abducts digit 5 Flex. Digiti Minimi Brevis

Proximal Attachment: Hook of hamate & flex. Retinaculum Distal Attachment:Medial side of base of proximal phalanx of little finger Innervation:Deep branch of ulnar (C8 & T1) Main Action:Flexes proximal phalanx of digit 5 Opponens Digiti Minimi

Proximal Attachment: Hook of hamate & flex. retinaculum Distal Attachment:Medial border of 5th metacarpal Innervation:Deep branch of ulnar (C8 & T1) Main Action:Draws 5th metacarpal anteriorly & rotates it, bringing digit 5 into opposition with thumb SHORT MUSCLES

Lumbricals 1 & 2 Lumbricals 3 & 4 Dorsal interossei 1-4 Palmar interossei Lumbricals 1 & 2 Proximal Attachment: Lateral 2 tendons of flexor digitorum profundus (unipennate muscles) Distal Attachment:Lateral sides of extensor expansions of 2-5 Innervation: Deep branch of ulnar nerve (C8 & T1) Main Action:Flex digits at metacarpo- phalangeal joints & extend interphanalgeal joints Lumbricals 3 & 4 Proximal Attachment: Medial 3 tendons of flexor digitorum profundus (bipennate muscles) Distal Attachment:Lateral sides of extensor expansions of 2-5 Innervation:Deep branch of ulnar nerve (C8 & T1) Main Action:Flex digits at metacarpo- phalangeal joints & extend interphanalgeal joints Dorsal Interossei 1-4

Proximal Attachment: Adjacent sides of 2 metacarpals (bipennate muscles) Distal Attachment:Extensor expansions & bases of proximal phalanges of digits 2-4 Innervation: Deep branch of ulnar nerve (C8 & T1) Main Action:Abducts digits from axial line & act with lumbricals to flex metacarpophalangeal joints and extend interphalangeal joints Palmar Interossei

Proximal Attachment: Palmar surfaces of 2nd, 4th, & 5th metacarpals (unipennate muscles) Distal Attachment:Extensor expansion of digits & bases of proximal phalanges of digits 2, 4, 5 Innervation:Deep branch of ulnar nerve (C8 & T1) Con’t Palmar Interossei

Main Action:Adducts digits toward axial line & assists lumbricals in flexing metacarpophalangeal joints & extending interphalangeal joints INTEROSSEI Common Injuries of the Wrist and Hand Bony Injuries Wrist Fractures

Acute onset ROM testing is not Tensile, compressive, or applicable shear forces Radial and ulnar pulses Usually hyperextension should be located mechanism Colle’s Fx – Deformity of the long dorsal displacement bones may be felt or seen (silver fork deformity) Swelling occurs rapidly Smith’s Fx – palmar displacement Metacarpal Fractures

Acute onset Compressive or shear forces Pain, swelling, & pt. tenderness along shaft Deformity may be present ex. Boxer’s Fx – 4th or 5th metacarpal fx results in shortening of the knuckle ROM may be limited due to pain Positive compression test Metacarpal Fractures (cont.)

Bennet’s Fx 1st metacarpal Shear force Crepitus present around joint False joint motion may be present Distal fx will be displaced due to pull of adductor pollicus longus Scaphoid Fractures

Acute onset from a crushing mechanism Pain, swelling, & pt. tenderness present in the anatomical snuff box A&PROM painful with ext. and ulnar dev. Grip strength may be reduced If suspected, should be treated as such until ruled out by a physician Radiograph images may not reveal the injury for several weeks Lunate Dislocations

Acute onset Forced hyperextension Deformity may be mechanism seen due to Pain present in lateral displacement on the wrist and hand palmar or dorsal ROM in all planes aspect of the hand limited due to pain Ligamentous Injury Wrist Sprains

Acute onset A&PROM limited as Tensile force usually ligament is placed on a from hyperextension stretch or hyperflexion 3rd degree may reveal mechanism joint instabilities Pain, swelling, and pt. Conclusion of a sprain tenderness along joint often based on line consistent with exclusion of other degree of injury wrist injuries UCL Sprain of the Thumb “Gamekeeper’s Thumb” Acute onset due to a combination of hyperextension and abduction Chronic onset due to repetitive motions of flexion and adduction Pain and pt. tenderness present over ulnar border of the joint Swelling localized over the thenar eminence PROM reveals pain with ext. and abd. A&RROM reveal pain with flex. and add. Positive valgus stress test of the thumb Collateral Ligament Sprains of the Fingers Acute onset “jamming” mechanism Can occur at MCP, PIP, or DIP joints Pain, swelling, & pt. tenderness present over affected joint ROM reduced due to pain and swelling Positive varus or valgus stress test of the affected joint Instability of joint consistent with degree of sprain Muscular Injuries Trigger Finger

Chronic onset Sheath becomes more From repetitive trauma stenotic as condition continues and finger to flex. tendon sheath may require assistance Thickening of the to return to extension tendon results in a Signs and symptoms catching or snapping of tenosynovitis as it passes through present the sheath during Usually seen in 3rd & flexion 4th digits Flexor Tendon Avulsion “Jersey Finger” Acute onset From sudden forced extension Affects the flexor digitorum profundus Immediate pain, swelling, and pt. tenderness exist on distal palmar phalanx Complete rupture will reveal inability to flex the DIP joint Incomplete rupture will reveal weakness with flexion of the DIP joint Extensor Tendon Avulsion “Mallet Finger” Acute onset From sudden forced flexion of the distal extensor tendon Immediate pain, swelling, and pt. tenderness on the distal dorsal phalanx Complete rupture will reveal inability to extend the DIP joint Bony avulsion often occurs but surgery intervention can be prevented if splinted early Extensor Tendon Rupture “Boutonneire Deformity” Acute onset From forced flexion of the PIP joint Pain, swelling, and pt. tenderness present at the PIP joint and the tendon’s insertion Disruption leads to central slip of the tendon’s lateral bands causing permanet ext. of DIP joint and flex, of the PIP joint Volar Plate Rupture

“Swan Neck Deformity”- Acute onset disruption of distal From forced attachment causing hyperextension of the PIP permanent hyperextension joint “Pseudoboutenniere Pain, swelling, and pt. Deformity”- tenderness present over disruption of proximal palmar aspect thumb attachment causing a flexion contracture De Quervain’s Syndrome

Chronic onset From repetitive stress involving ulnar dev. Pain and swelling present over the radial styloid process, thenar eminence, extensor pollicus brevis, and abductor pollicus longus De Quervain’s Syndrome (cont.)

AROM painful with radial & ulnar deviation of the wrist as well as flexion & adduction of the thumb PROM painful with ulnar deviation of the wrist as well as flexion & adduction of the thumb RROM painful with radial deviation of the wrist as well as extension & abduction of the thumb Positive Finkelstein’s test Other Injuries Injury to the Triangular Fibrocartilage Acute onset From forced hyperextension creating a compressive force No swelling is immediately present but pain and pt. tenderness appear along the medial half of the wrist distal to the ulna A&PROM limited in extension Easily confused with UCL sprain or the wrist but symptoms of fibrocartilage injury will persist longer than would a sprain Carpal Tunnel Syndrome

AROM may be limited Chronic onset due to stiffness From repetitive flexion PROM may increase and extension of the wrist symptoms with full Parasthesia and pain run flexion and extension along the wrist, hand, and RROM reveals decreased fingers following the strength of abd. pollicus distribution of the median brevis nerve Positive Tinel’s sign Positive Phalen’s test Synovial Cyst “Wrist Ganglion”

Chronic onset Observable mass Occurs following a present sprain or strain May or may not be Due to a weakened painful and limit ROM synovial sheath (usually depends on allowing fluid to location in wrist) escape