GA Forearm Muscles, Vasculature and Innervation Flashcards
Muscles of Forearm
flexors and pronators are in the anterior compartment
-served by median n. and branches
-supplied by radial and ulnar arteries
extensors and supinators are in the posterior compartment
-innervated by radial nerve and branches
Superficial Flexor Compartment
Pronator teres muscle
Flexor Carpi Radialis muscle
Palmaris longus muscle
Flexor Carpi Ulnaris muscle
Intermediate Flexor Compartment
Flexor Digitorum superficialis Muscle
Depp Flexor Compartment
Flexor Digitorum profundus muscle
Flexor Pollici longus muscle
Pronator quadratus muscle
Pronator Teres Muscle
most lateral of the forearm flexors
O- Ulnar head - coronoid process
Humeral head - medial epicondyle via common flexor tendon
I - Middle of convexity of lateral surface of radius
A - Pronation and flexion of forearm
N - Median n. (C6,C7)
Flexor Carpi Radialis Muscle
medial to pronator teres, tendon does not pass thru carpal tunnel, Radial a. lies just lateral to this muscle
O- Medial epicondyle via common flexor tendon
I - Base of 2nd metacarpal
A - Flexion and radial deviation of the hand
N - Median n. (C6,C7)
Palmaris Longus muscle
absent in one or both sides of people, passes superficial to flexor retinaculum, tendon lies deep and slightly medial to median n. at wrist
O- medial epicondyle via common flexor tendon
I - Distal 1/2 flexor retinaculum and apex of palmar aporneurosis
A - Flexion of hand at wrist and tenses palmar aponeurosis
N - Median n. (C7,C8)
Flexor Carpi Ulnaris muscle
most medial of superficial flexors, tendon is guide to ulnar n. and a. on lateral side at wrist
O - Humeral head - medial epicondyle via common flexor tendon
Ulnar head - Olecranon and posterior border via aperneurosis
I - Pisiform, hook of hamate and 5th metacarpal
A - Flexion and ulnar deviation of hand
N - Ulnar n. (C7,C8)
Flexor Digitorum Superficialis muscle
median n. and ulnar n. enter forearm by passing b/w its two heads, gives rise to 4 tendons at wrist
O - Humeroulnar head - medial epicondyle via common flexor tendon and coronoid process
Radial head - superior 1/2 anterior border
I - Shafts of middle phalanges of medial 4 digits via split tendon
A - flexion of PIP’s; strong flexion of MP’s; flexion of wrist
N - Median n. (C7,C8,T1)
Flexor Digitorum Profundus muscle
only muscle that can flex DIP’s, gives rise to 4 tendons at wrist
O - medial and lateral halves: proximal 3/4 medial and anterior surfaces of ulna and interosseous membrane
I - Medial half - Basses of phalanges of 4th and 5th digits
Lateral half - Basses of phalanges of 2nd and 3rd digits
A - Medial half - Flexes DIP’s of 4th and 5th
Lateral half - Flexes DIP’s of 3rd and 2nd
N - Medial half - Ulnar n. (C8,T1)
Lateral half - A.I.N. (C8,T1)
Flexor Pollicis Longus muscle
lies lateral to FDP, passes thru the carpal tunnel
O - Anterior surface of radius and adjacent interosseous membrane
I - base of distal phalanx of thumb
A - Flexion of thumb; flexion of wrist
N - A.I.N. (C8,T1)
Pronator Quadratus muscle
deepest muscle in anterior forearm, costal distal radius, ulna and interosseous membrane, A.I.A. and A.I.N. pass deep to this muscle
O - Distal 1/4 of anterior surface of ulna
I - Distal 1/4 of anterior surface of radius
A - Prime mover for forearm pronation; deep fibers bind radius and ulna together
N - A.I.N. (C8,T1)
Superficial Extensor Compartment
Brachioradialis muscle Extensor Carpi Radialis longus muscle Extensor Carpi Radialis brevis muscle Extensor Digitorum Muscle Extensor Digiti Minimi muscle Extensor Carpi Ulnaris muscle
Depp Extensor Compartment
Supinator Muscle
Extensor Indicis muscle
Outcropping Extensor Muscle
Abductor Pollicis Longus muscle
Extensor Pollicis Longus muscle
Extensor Pollicis Brevis muscle
Brachioradialis muscle
lies on anterolateral surface of forearm, forms lateral border of cubital fossa, functionally a flexor, but is innervated by radial nerve, overlies radial n. and a. proximally, does not cross wrist joint
O - Proximal 2/3 of lateral supracondylar ridge
I - Lateral surface of distal end of radius proximal to styloid process
A - Forearm flexion (maximal in mid-pronated/mid-supinated position)
N - Radial n. (C5,C6,C7)
Extensor Carpi Radialis Longus muscle
partially overlapped nu brachioradialis m., distal tendon is crossed over by Abductor Pollicis longus and Extensor Pollicis brevis
O - Lateral supracondylar ridge
I - Dorsal aspect, base of 2nd metacarpal
A - Ext. and radial deviation of wrist
N - Radial n. (C6,C7)
Extensor Carpi Radialis Brevis muscle
shorter that ECRL because it arises distally
O - Lateral epicondyle of humerus via common extensor tendon
I - Dorsal aspect, base of 3rd metacarpal
A - Ext. and radial deviation of wrist
N - Deep branch of radial n. (C7,C8)
Extensor Digitorum Muscle
principle extonsor of medial 4 digits, tendons spread out on dorsum of hand as they pass the digits
O - Lateral epicondyle via common extensor tendon
I - Extensor expansion of medial 4 digits
A - Ext. of medial 4 digits primarily at metaphalanges, secondarily at intermediate phalanges, ext of wrist
N - Deep branch of radial n. (C7,C8)
Extensor Digiti Minimi muscle
partially detached part of extensor digitorum m.
O - Lateral epicondyle via common extensor tendon
I - Extensor expansion of 5th digit
A - Extension of 5th digit primarily at metaphalange, secondarily at Intermediate phalanges, assists with wrist ext.
N - Deep branch of radial n. (C7,C8)
Extensor Carpi Ulnaris muscle
located on medial border of forearm, has humeral and ulnar heads
O - Lateral epicondyle via common extensor tendon, posterior border of ulna via shared aponeurosis
I - Dorsal aspect, base of 5th metacarpal
A - Ext and ulnar deviation of wrist
N - Deep branch of radial n. (C7,C8)
Supinator muscle
helps form floor of cubital fossa
O - Lateral epicondyle, radial collateral and anular ligaments, supinator fossa, crest of ulna
I - Lateral, posterior, and anterior surfaces of proximal 1/3 or radius
A - Supination of forearm, especially slow, unopposed with extended forearm
N - Deep branch of radial n. (C7,C8)
Extensor Indicis muscle
part of deep extensor group, lies medial and alongside Extensor pollicis longs, confers independence to index finger
O - Posterior surface of distal 1/3 ulna and interosseous membrane
I - Extensor expansion of 2nd digit; assits with wrist extension
A - Extension of 2nd digit (independent extension)
N - P. I. N. (C7,C8)
Abductor Pollicis Longus muscle
lies just distal to supinator muscle, tendon and belly may be split into 2, forms one border of the snuffbox
O - Posterior surface of proximal halves of ulna, radius and interosseous membrane
I - Base of 1st metacarpal
A - ABD of thumb, ext. of CM
N - P.I.N. (C7,C8)
Extensor Pollicis Brevis muscle
tendon lies parallel and immediately medial to APL but extends further, forms one border of anatomical snuffbox
O - Posterior surface distal 1/3 of radius of interosseous membrane
I - dorsal aspect, base of proximal phalanx of thumb
A - Extension of proximal phalanx of thumb at MP, ext. of CM, assists with ext. and radial deviation
N - P.I.N. (C7,C8)
Extensor Pollicis Longus muscle
tendon passes medial to the dorsal tubercle of radius, form one border of the anatomical snuffbox
O - Posterior surface middle 1/3 of ulna and interosseous membrane
I - Dorsal aspect, base of distal phalanx of thumb
A - Extension of distal phalanx at IP, ext. of MP’s and CM’s
N - P.I.N. (C7,C8)
