The anterior interosseous artery is the largest branch of the common interosseous artery, a branch of the ulnar artery. It descends on the anterior surface of the interosseous membrane between the flexor digitorum profundus and flexor pollicis longus, giving branches that supply the deep forearm flexors and both bones of the forearm, before piercing the interosseous membrane to contribute to the dorsal wrist anastomosis.
The anterior interosseous artery is the primary blood supply to the radius and ulna diaphyses and is at risk during forearm fracture plating and during pronator teres release for pronator syndrome. It is the dominant artery used in vascularised bone grafts from the forearm radius. The anterior interosseous nerve runs alongside the artery on the anterior interosseous membrane, making the two structures companions that are commonly assessed together in forearm compartment syndrome.
Compression of the anterior interosseous nerve (and its accompanying artery) by the fibrous edge of pronator teres, FDS, or accessory muscle produces selective weakness of FDP to the index and FPL, causing inability to form an OK sign, without sensory loss.
Elevated pressure in the volar forearm compartment compromises flow through the anterior interosseous artery and other vessels, producing the classic features of pain with passive stretch, tense compartment, and paresthesia, requiring emergent fasciotomy.
