Forearm Muscles Flashcards
pronator teres proximal attachment
ulnar head- coronoid process
humeral head- medial epicondyle, common flexor origin
pronator teres distal attachment
middle of convexity of lateral surface of radius
pronator teres innervation
Median nerve (C6, C7)
pronator teres muscle action
pronates and flexes forearm at elbow
flexor carpi radialis (FCR) proximal attachment
medial epicondyle, common flexor origin
flexor carpi radialis (FCR) distal attachment
base of 2nd metacarpal
FCR innervation
Median nerve (C6, C7)
FCR muscle action
flexes and abducts wrist
palmaris longus proximal attachment
medial epicondyle, common flexor origin
palmaris longus distal attachment
distal half of flexor retinaculum, apex of palmar aponeurosis
palmaris longus innervation
median nerve (C7, C8)
palmaris longus muscle action
flexes hand (at wrist) and tenses palmar aponeurosis
flexor carpi ulnaris (FCU) proximal attachment
humeral head: medial epicondyle, common flexor origin
ulnar head: olecranon and posterior border of ulna via aponeurosis
FCU distal attachment
pisiform, hook of hamate, 5th metacarpal
FCU innervation
ulnar nerve (C7, C8)
FCU muscle action
flexes and adducts hand at wrist
Flexor digitorum superficialis proximal attachment
humero-ulnar head: medial epicondyle, common flexor origin AND coronoid process
radial head: superior half of anterior border of radius
FDS distal attachment
shafts of middle phalanges of medial four digits
FDS innervation
median nerve (C7, C8, T1)
FDS muscle action
flexes middle phalanges at proximal interphalangeal joints, also flexes proximal phalanges at metacarpophalangeal joints
Flexor digitorum profundus (FDP) proximal attachment
medial and lateral parts: proximal 3/4 of medial and anterior surface of ulna and interosseous membrane
FDP distal attachment
medial part: bases of distal phalanges of 4th and 5th digits
lateral part: bases of distal phalanges of 2nd and 3rd digits
FDP medial part innervation
ulnar nerve (C8, T1)
FDP muscle action
medial part: flexes distal phalanges 4 and 5 at distal interphalangeal joints
lateral part: flexes distal phalanges 2 and 3 at distal interphalangeal joints
Flexor pollicis longus (FPL) proximal attachment
anterior surface of radius and adjacent interosseous membrane
FPL distal attachment
base of distal phalanx of thumb
FPL innervation
anterior interosseous nerve, from median nerve (C8, T1)
FPL muscle action
flexes phalanges of thumb
Pronator quadratus proximal attachment
distal 1/4 of anterior surface of ulna
pronator quadratus distal attachment
distal 1/4 of anterior surface of radius
pronator quadratus innervation
anterior interosseous nerve from median nerve (C8, T1)
pronator quadratus muscle action
pronates forearm, deep fibers bind radius and ulna together
FDP lateral part innervation
anterior interosseous nerve from median nerve (C8, T1)
brachioradialis proximal attachment
proximal 2/3 of supra-epicondylar ridge of humerus
brachioradialis distal attachment
lateral surface of distal end of radius proximal to styloid process
brachioradialis innervation
radial nerve (C5, C6, C7)
brachioradialis muscle action
relatively weak flexion of forearm; strongest when forearm is in midpronated position
extensor carpi radialis longus (ECRL) proximal attachment
lateral supra-epicondylar ridge of humerus
ECRL distal attachment
dorsal aspect of base of 2nd metacarpal
ECRL innervation
radial nerve (C6, C7)
Extensor carpi radialis brevis (ECRB) proximal attachment
lateral epicondyle; common extensor origin
ECRB distal attachment
dorsal aspect of base of 3rd metacarpal
ECRB innervation
deep branch of radial nerve (C7, C8)
ECRB muscle action
extend and abduct hand at wrist joint
Extensor digitorum proximal attachment
lateral epicondyle, common extensor origin
extensor digitorum distal attachment
extensor expansions of medial 4 digits
extensor digitorum innervation
deep branch of radial nerve (C7, C8)
extensor digitorum muscle action
extends medial four digits at metacarpophalangeal joints, secondarily at interphalangeal joints
extensor digiti minimi (EDM) proximal attachment
lateral epicondyle, common extensor origin
EDM distal attachment
extensor expansion of 5th digit
EDM innervation
deep branch of radial nerve (C7, C8)
EDM muscle action
extends 5th digit primarily at metacarpophalangeal joint, secondarily at interphalangeal joint
ECRL muscle action
extend and abduct hand at wrist joint; active during fist clenching
Extensor carpi ulnaris (ECU) proximal attachment
lateral epicondyle of humerus; posterior border of ulna via shared aponeurosis
ECU distal attachment
dorsal aspect of base of 5th metacarpal
ECU innervation
deep branch of radial nerve (C7, C8)
ECU muscle action
extends and adducts hand at wrist joint (also active during fist clenching)
supinator proximal attachment
lateral epicondyle of humerus; radial collateral and anular ligaments; supinator fossa, crest of ulna
supinator distal attachment
lateral, posterior, and anterior surfaces of proximal 1/3rd of radius
supinator innervation
deep branch of radial nerve (C7, C8)
supinator muscle action
supinates forearm; rotates radius to turn palm anteriorly or superiorly (if elbow is fixed)
extensor indicis (EI) proximal attachment
posterior surface of distal third of ulna and interosseous membrane
Extensor indicis muscle action
extends 2nd digit (enabling independent extension), helps extend hand at wrist
Abductor pollicis longus (APL) proximal attachment
posterior surface of proximal halves of ulna, radius, and interosseous membrane
APL distal attachment
base of 1st metacarpal
APL innervation
posterior interosseous nerve, continuation of deep branch of radial nerve (C7, C8)
APL muscle action
abducts thumb and extends it at carpometacarpal joint
Extensor pollicis longus (EPL) proximal attachment
posterior surface of middle third of ulna and interosseous membrane
EPL distal attachment
dorsal aspect of base of distal phalanx of thumb
EPL innervation
posterior interosseous nerve, continuation from deep branch of radial nerve, (C7, C8)
EPL muscle action
extends distal phalanx of thumb at interphalangeal joint, extends metacarpophalangeal and carpometacarpal joints
Extensor pollicis brevis (EPB) proximal attachment
posterior surface of distal 1/3rd of radius and interosseous membrane
EPB distal attachment
dorsal aspect of base of proximal phalanx of thumb
EPB innervation
posterior interosseous nerve, continuation of deep branch of radial nerve, (C7, C8)
EPB muscle action
extends proximal phalanx of thumb at metacarpophalangeal joint, extends carpometacarpal joint
Extensor Indicis distal attachment
extensor expansion of 2nd digit
extensor indicis innervation
posterior interosseous nerve, continuation of deep branch of radial nerve (C7, C8)