Forearm extensor

Question 1

Name the seven superficial extensor muscles of the forearm

Answer 1

Brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, anconeus.

Question 2

Name the five deep muscles of the extensor compartment of the forearm

Answer 2

Supinator, abductor pollicis longus, extensor pollicis longer, extensor pollicis brevis, extensor indicis.

Question 3

Four groups each three muscles- act on…

Answer 3

Act on wrist: Extensor carpi radialis longus and brevis, extensor carpi ulnaris
Act on thumb: Abductor policies longs and brevis, extensor pollicis longus.
Extend digits: Extensor digitorum longus, extensor digiti minimi, extensor indicis
Act on forearm only: Brachioradialis, anconeus, supinator

Question 4

What nerve supplies all of the extensor compartment muscles

Answer 4

Radial nerve

All muscles inverted by the interosseous branch except brachioradialis and ECRL

Question 5

What is the blood supply to the posterior compartment of the forearm

Answer 5

Posterior interosseous artery (a branch from the common interosseous off the ulnar)

Question 6

What muscles insert into the common extensor tendon and where does it originate

Answer 6

Extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, extensor carpi radialis brevis. inserts into the lateral epicondyle of the humerus

Question 7

Where do the tendons of the extensor digitorum insert

Answer 7

Into the proximal and distal phalanges (it splits)

Question 8

What does anconeus do

Answer 8

Extends the elbow

Question 9

Discuss the path of the radial nerve

Answer 9

From the posterior cord of the brachial plexus. Runs posterior to the humerus supplying the triceps brachii. Comes anterior at the cubital fossa through the proximal head of brachioradialis over the lateral epicondyle of the humerus. Then splits to give the deep and superficial branches. Deep branch travels through the two heads of supinator muscle where it becomes the posterior interosseous nerve and gives motor supply to all the forearm extensor muscles. The superficial descends with the radial artery deep to brachioradialis (lateral side) then passes over anatomical snuff box to innervate dorsolateral 3.5 digits