Forearm Deep Extensors Flashcards
Which muscles are deep layer extensors of the forearm?
Supinator, extensor indicis and outcropping muscles
Which muscles are the outcropping muscles of the deep layer?
Abductor pollicis longus, extensor pollicis longus and brevis
What are the attachment sites for supinator muscle?
O: lateral humeral epicondyle, radial collateral L of the elbow, annular L of the proximal radioulnar L, supinator crest and supinator fossa of ulna
I: proximal aspect of the radial body
What is the action for supinator?
Supinate forearm
What is the supinator muscle innervated by?
Deep radial N
What are the deep layer forearm extensor muscles innervated by?
Posterior interosseous N
Exception: supinator
What are the attachment sites for extensor indicis?
O: posterior aspect of the distal ulna and interosseous membrane
I: extensor expansion of digit 2
What is the action of extensor indicis?
Extend hand at the wrist and extend 2nd digit
What are the attachment sites for abductor pollicis longus?
O: posterior aspect of the proximal ulna, radius and interosseous membrane
I: base of the 1st metacarpal
What is the action of abductor pollicis longus??
Abduct hand at the wrist
Abduct the pollux at the carpometacarpal joint
What are the attachment sites for extensor pollicis longus?
O: posterior aspect of ulna and interosseous membrane
I: dorsal aspect of the base of the distal phalanx of the pollux
What are the actions for extensor pollicis longus?
Abduct hand at the wrist
Extend 1 metacarpal, proximal and distal phalanges of the pollux at the carpometacarpal, MP and DIP and PIP joints
What are the attachment sites of extensor pollicis brevis?
O: posterior aspect of radius and interosseous membrane
I: dorsal aspect of the base of the proximal phalanx of the pollux
What are the actions for extensor pollicis brevis?
Abduct hand, extend 1st metacarpal and proximal phalanges of the pollux at the carpometacarpal and MP joints
