The Forearm Flashcards
In general, where do the flexors of the forearm originate from?
medial epicondyle of humerus via common flexor tendon
How many layers can the forearm flexors be organized into?
3 layers - superficial, intermediate, and deep
What are the general basic functions of the muscles in the flexor compartment of the forearm?
- actively flex digits
- actively flex, abduct and adduct the hand at the wrist
- initiate or assist pronation of the hand (rotate radius)
- act to a lesser degree to flex the forearm
What nerve serves to innervate most of the muscles in the flexor compartment of the forearm?
median nerve (exception is flexor carpi ulnaris, ulnar nerve)
What serves as the lateral border between the flexor and extensor compartments of the forearm?
brachioradialis muscle
What does the flexor retinaculum attach to in order to create a fibro-osseous canal known as the carpal tunnel?
laterally: trapezium and tubercle of scaphoid
medially: hamulus of hamate and pisiform
What transverse the carpal tunnel?
tendons of intermediate and deep layer musculature as the median nerve
What muscle is responsible for fine movements of the digits?
flexor digitorum profundus
The profundus must pass through the apertures w/in the tendons of what muscle?
flexor digitorum superficialis
In general, where do the muscles of the extensor compartment of the forearm originate from?
lateral epicondyle of the ulna
How many layers are the muscles of the extensor compartment of the forearm arrange into?
2 layers - superficial (5 muscles) and deep (5 muscles)
The tendons of what muscles form the ‘anatomical snuff box’?
posterior - extensor pollicis longus
anterior/superiorly - extensor pollicis brevis and abductor pollicis longus
(floor is scaphoid bone)
What can be located crossing the floor of the “anatomical snuff box”?
radial artery
What are the 4 branches coming off the radial artery in the forearm?
- radial recurrent a.
- muscular branches
- palmar carpal branch
- superficial palmer branch
What branch of the radial artery arises just before it passes to the dorsum and participates in the formation of the superficial palmer arterial arch?
superficial palmer branch
What branch of the radial artery ascends radial on the surface of the supinator muscle to anastomose with the radial collateral branch of the deep brachial artery?
radial recurrent a.
What are the 7 branches coming off the ulnar artery in the forearm?
- anterior ulnar recurrent
- posterior ulnar recurrent a.
- common interosseous a.
- muscular branches
- palmer carpal branch
- dorsal carpal branch
- deep palmar branch
What are the 2 branches the common interosseous a. from the ulnar a. form?
- anterior interosseous a.
- posterior interosseous artery (PIA) (branches to interosseous recurrent a.)
What nerve supplies innervation to all but one of the muscles of the anterior forearm?
median nerve (C6-T1)
What nerve branches off the median n to accompany the anteriro interosseous artery and innervat the msucles of hte deep layer of flexor muscles of the forearm?
anterior interrosseous nerve
What is the last branch of the median nerve which arises proximal to the flexor retinaculum?
palmer cutaneous branch
What is the median nerve susceptible to?
compression by inflammation of the flexor retinaculum (carpal tunnel syndrome)
What nerve course posterior to the medial epicondyl of the humerus and enters the forearm by passing between the two heads of origin of the flexor carpi ulnaris? The nerve enters the wrist by passing superficial to the flexor retinaculum lateral to the pisiform
ulnar nerve ((C8, T1)
What are the two nerve branches from the radial nerve in the forearm?
- superficial branch
- deep branch (posterior interosseous n.)
