Dorlands/Elsevier n_05/12565987 FMA 77559 | TA A14.2.03.055 | |
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Innervates Extensor carpi radialis brevisExtensor digitorumExtensor digiti minimiExtensor carpi ulnarisSupinator muscleAbductor pollicis longusExtensor pollicis brevisExtensor pollicis longusExtensor indicis Latin nervus interosseus antebrachii posterior | ||
The posterior interosseous nerve (or dorsal interosseous nerve) is a nerve in the forearm. 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.
Contents
Course
It descends along the interosseous membrane, anterior to the extensor pollicis longus muscle, 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, except the Anconæus, Brachioradialis, Extensor carpi radialis longus. In other words, it supplies the following muscles:
Entrapment
The posterior interosseous nerve may be entrapped at the Arcade of Frohse, which is part of the Supinator muscle. Posterior interosseous neuropathy is purely a motor syndrome resulting in finger drop, and radial wrist deviation on extension.