Muscles of posterior compartment of forearm Flashcards
What is the proximal attachment of the brachioradialis?
Proximal 2/3 of supra-epicondylar ridge of humerus
What is the distal attachment of the brachioradialis?
Distal end of radius proximal to styloid process
What nerve innervates the brachioradialis?
Radial nerve (C5,C6,C7)
What is the muscle action of the brachioradialis?
Relatively weak flexion of forearm
What is the proximal attachment of the extensor carpi radialis longus?
Lateral supra-epicondylar ridge of humerus
What is the distal attachment of the extensor carpi radialis longus?
Dorsal aspect of base of 2nd metacarpal
Whatnerve innervates the the extensor carpi radialis longus?
Radial nerve (C6,C7)
What is the muscle action of the extensor carpi radialis longus and the extensor carpi radialis brevis?
Extend and abduct hand at the wrist joint
Longus: is active during fist clenching
What is the proximal attachment of the extensor carpi radialis brevis, extensor digitorum, and the extensor digiti minimi
Lateral epicondyle of humerus
What is the distal attachment of the extensor carpi radialis brevis?
Dorsal aspect of base of 3rd metacarpal
What nerve innervates the extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris?
Deep branch of radial nerve (C7,C8)
What is the distal attachment of the extensor digitorum?
Extensor expansions of medial four digits
What is the muscle action of the extensor digitorum?
Extends medial four digits primarily at metacarpophalangeal joints
What is the distal attachment of the extensor digiti minimi?
Extensor expansion of 5th digit
What is the muscle action of the extensor digiti minimi?
Extends 5th digit primarily at metacarpophalangeal joint
What is the proximal attachment of the extensor carpi ulnaris?
Lateral epicondyle of humerus and posterior border of ulna
What is the distal attachment of the extensor carpi ulnaris?
Dorsal aspect of base of 5th metacarpal
What is the muscle action of the extensor carpi ulnaris?
Extends and adducts hand at wrist joint (also active during first clenching)
What is the proximal attachment of the supinator?
Lateral epicondyle of humerus,
Radial collateral and angular ligaments,
Supinator fossa,
Crest of ulna
What is the distal attachment of the supinator?
Lateral, posterior, and anterior surfaces of proximal third of radius
What nerve innervates the supinator?
Deep branch of radial nerve (C7,C8)
What is the muscle action of the supinator?
Supinates forearm, rotates radius to turn palm anteriorly or superiorly (if elbow is flexed)
What is the proximal of the attachment of the extensor indicis?
Posterior surface of distal third of ulna and interosseous membrane
What is the distal attachment of the extensor indicis?
EXtensor expansion of the 2nd digit
What is the proximal attachment of the abductor pollicis longus?
Posterior surface of proximal halves of ulna, radius, and interosseous membrane.
What is the distal attachment of the abductor pollicis longus?
Base of 1st metacarpal
What nerve innervates the abductor pollicis longus, extensor pollicis longus, and the extensor pollicis brevis?
Posterior interosseous nerve (C7,C8), continuation of deep branch of radial nerve.
What is the muscle action of the abductor pollicis longus?
Abducts thumb and extends it at carpometacarpal joint
What is the proximal attachment of the extensor pollicis longus?
Posterior surface of middle third of ulna and interosseous membrane
What is the distal attachment of the extensor pollicis longus?
Dorsal aspect of base of distal phalanx of thumb
What is the muscle action of the extensor pollicis longus?
Extends distal phalanx of thumb at interophalangeal joint, and extents metacarpophalangeal and carpometacarpal joints.
What is the proximal attachment of the extensor pollicis brevis?
Posterior surface of distal third of radius and interosseous membrane.
What is the distal attachment of the extensor pollicis brevis?
Dorsal aspect of base of proximal phalanx of thumb.
What is the muscle action of the extensor pollicis brevis?
Extends proximal phalanx of thumb at metacarpophalangeal joint, and extends carpometacarpal joint.
