The anterior interosseous nerve also known as the volar interosseous nerve arises from the median nerve in the forearm, and supplies the flexor pollicis longus, pronator quadratus and the lateral portion of flexor digitorum profundus.
The anterior interosseous nerve continues as a major branch of the median nerve and receives fibres from the C5-T1 spinal nerve roots.
The anterior interosseous nerve arises from the median nerve as it passes between the two heads of the pronator teres muscle. It then descends vertically on the anterior aspect of the interosseous membrane between flexor digitorum profundus and flexor pollicis longus. The nerve then passes deep to the pronator quadratus muscle, which it supplies. The anterior interosseous nerve sends articular branches to the anterior aspect of the wrist.
Branches and Supply
The anterior interosseous nerve supplies the deep layer of the muscles in the anterior compartment of the forearm. These are:
- lateral part of flexor digitorum profundus (which has insertions at the 2nd and 3rd phalanges)
- flexor pollicis longus
- pronator quadratus
The anterior interosseous nerve provides sensory fibres to the carpals, however does not have cutaneous branches.
The anterior interosseous nerve runs with anterior interosseous branch of the ulnar artery, which also passes along the anterior aspect of the interosseous membrane.
The anterior interosseous nerve may be compressed along its course most commonly at the tendinous edge of the deep head of the pronator teres muscle, causing anterior interosseous nerve syndrome.