Extrinsic Muscles Acting on the Wrist and Hand Flashcards
Abductor Pollicis Longus
Act: 1st CMC joint abduction, 1st CMC joint extension, assists in radial deviation of the wrist
O: posterior surface of the distal ulna, posterior surface of the distal radius, and adjoining interosseous membrane
I: Radial side of the base of the 1st metacarpal
Innervation: Median
Extensor Carpi Radialis Brevis
Act: Wrist extension and radial deviation
O: Lateral epicondyle via the common extensor tendon and radial collateral ligament
I: Base of 3rd metacarpal
Innervation: Radial
Extensor Carpi Radialis Longus
Act: Wrist extension and radial deviation
O: Supracondylar ridge of humerus
I: Radial side of the base of the 2nd metacarpal
Innervation: Radial
Extensor Carpi Ulnaris
Act: Wrist extension and ulnar deviation
O: Lateral epicondyle via the common extensor tendon
I: Ulnar side of the base of the 5th metacarpal
Innervation: Deep Radial
Extensor Digiti Minimi
Act: 5th MCP joint extension, 5th DIP and PIP extension, working with the lumbricals and interossei
O: Lateral epicondyle via the common extensor tendon and deep antebrachial fascia
I: To the middle and distal phalanx of 5th finger via the extensor digitorum tendon
Innervation: Radial
Extensor Digitorum Communis
Act: Wrist extension, MCP extension, IP extension, radial deviation of wrist
O: Lateral epicondyle via the common extensor tendon
I: Dorsal surface of the proximal base of the middle and distal phalanges of each of the four fingers
Innervation: Deep Radial
Extensor Indicis
Act: 2nd MCP extension (index finger), 2nd DIP and PIP extension, working with lumbricals and interossei
O: Posterior surface of the ulna, distal to the extensor pollicis longus, interosseous membrane
I: To the middle and distal phalanx of the index finger via the extensor digitorum tendon
Innervation: Radial
Extensor Pollicis Brevis
Act: 1st MCP joint extension, 1st CMC joint extension, 1st CMC joint abduction, assists in wrist radial deviation
O: Posterior surface of the distal radius and adjoining interosseous membrane
I: Dorsal surface of the base of the proximal phalanx of the thumb
Innervation: Deep Radial
Extensor Pollicis Longus
Act: 1st IP joint extension, 1st MCP joint extension, 1st CMC joint extension, assists in wrist extension, and assists in wrist radial deviation
O: Posterior surface of the middle one-third of the ulna and adjoining interosseous membrane
I: Dorsal surface of the base of the distal phalanx of the thumb
Innervation: Deep Radial
Flexor Carpi Radialis
Act: Wrist flexion, forearm pronation, radial deviation
O: Medial epicondyle via the common flexor tendon
I: Base of the 2nd and 3rd metacarpals
Innervation: Median
Flexor Carpi Ulnaris
Act: Wrist flexion and ulnar deviation
O: Humeral head: medial epicondyle via the common flexor tendon
Ulnar head: medial border of the olecranon and proximal two-thirds of the posterior ulna
I: Pisiform, hamate, and 5th metacarpal
Innervation: Ulnar
Flexor Digitorum Profundus
Act: DIP flexion, PIP flexion, wrist flexion
O: Anteromedial proximal three-fourths of ulna and associated interosseous membrane
I: Bases of the medial phalanges of digits 2-5
Innervation: Palmar interosseous
Flexor Digitorum Superficialis
Act: PIP flexion, MCP flexion, wrist flexion
O: Humeral head: medial epicondyle via the common flexor tendon and UCL
Ulnar head: coronoid process
Radial head: oblique line of radius
I: Sides of the middle phalanges of digits 2-5
Innervation: Median
Flexor Pollicis Longus
Act: 1st IP joint flexion, 1st MCP joint flexion, assists in wrist flexion
O: Anterior surface of the radius, adjoining interosseous membrane, coronoid process of ulna
I: Palmar surface of the base of the distal phalanx of the thumb
Innervation: Palmar interosseous
Palmaris Longus
Act: Wrist flexion
O: Medial epicondyle via the common flexor tendon
I: Flexor retinaculum and palmar aponeurosis
Innervation: Median
