Posterior compartment of forearm (Outcropping muscles of deep layer) Flashcards
What are the outcropping muscles in the deep layer?
Abductor pollicis longus (APL)
Extensor pollicis longus (EPL)
Extensor pollicis brevis (EPB)
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 is the innervation of the abductor pollicis longus?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the main action of the abductor pollicis longus?
Abduct 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 innervation of the extensor pollicis longus?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the main action of the extensor pollicis longus?
Extends distal phalanx of thumb at interphalangeal joint; extends metacarpophalangeal and carpometacapal 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 innervation of the extensor pollicis brevis?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the main action of the extensor pollicis brevis?
Extends proximal phalanx of thumb at metacarpophalangeal joint; extends carpometacarpal joint
