ABSTRACT
From the posterior surface of the median nerve 2 to 8 cm distal to the medial humeral epicondyle originates an exclusively motor nerve branch, the anterior interosseous (palmaris) nerve. While initially paralleling the median nerve, the AIN soon dives under the deep fascial layer of the flexor digitorum superficialis (FDS) to run along the interosseous membrane between the flexor pollicis longus (FPL) laterally and flexor digitorum profundus (FDP) medially. It is accompanied by interosseal vessels. Distally, the nerve ends under the pronator quadratus (PQ), branching 2 to 5 cm distal to its origin. The anterior interosseous nerve supplies the FPL, the FDP to the second finger, and the PQ.
