MS L12 - Forearm Extensors

MS L12 - Forearm Extensors

1. All muscles of extensor compartment are innervated by radial nerve

2. extensor retinaculum prevents bowstringing but does not form a tunnel like the flexor retinaculum

3. 7 superficial extensor muscles of the forearm

   • Supracondylar ridge is origin
     • extensor carpi radialis longus
       • extends wrist
       • inserts onto base of 2nd metacarpal
     • Anconeus
       • Helps triceps with extension of elbow
     • Brachioradialis
       • in extensor/supinator compartment even though it FLEXES the elbow
       • acts as a shunt muscle for radius
       • Inserts onto base of radial styloid process
   • Common extensor tendon is origin
     • extensor carpi radialis brevis
       • inserts onto base of 3rd metacarpal
     • extensor carpi ulnaris
       • inserts onto base of 5th metacarpal
     • extensor digiti minimi
       • inserts onto digital expansion hood of 5th digit (pinky)
     • extensor digitorum
       • inserts onto digital expansion hood of fingers (not thumb)

4. 5 deep extensor muscles of the forearm