Posterior interosseous nerve

The posterior interosseous nerve (or dorsal interosseous nerve) is a nerve in the foream. It is the continuation of the deep branch of the radial nerve, after this has crossed the supinator muscle. It is considerably diminished in size compared to the deep branch of the radial nerve. The nerve fibers originate from cervical segments C7 and C8.

Course
It descends on the interosseous membrane, in front of the Extensor pollicis longus, to the back of the carpus, where it presents a gangliform enlargement from which filaments are distributed to the ligaments and articulations of the carpus.

Supply
It supplies all the muscles on the radial side and dorsal surface of the forearm, excepting the Anconæus, Brachioradialis, and Extensor carpi radialis longus. In other words, it supplies the following muscles:


 * Extensor carpi radialis brevis
 * Extensor digitorum
 * Extensor digiti minimi
 * extensor carpi ulnaris
 * Supinator muscle
 * Abductor pollicis longus
 * Extensor pollicis brevis
 * Extensor pollicis longus
 * Extensor indicis