The anterior interosseous artery is one of the two branches of the short common interosseous artery (from the ulnar artery). The artery courses deep in the anterior compartment of the forearm on the anterior surface of the interosseous membrane along with the anterior interosseous nerve (from the median nerve). It runs between flexor digitorum profundus (medially) and flexor pollicis longus (laterally) muscles supplying both. It gives off several small branches that pierce the interosseous membrane, supplying the deep extensor muscles within the posterior compartment of the forearm. Small nutrient vessels also supply the radius and ulna. At the upper border of pronator quadratus, the artery:

gives off a small branch to anastomose with the palmar carpal arch and,
pierces the interosseous membrane to enter the posterior compartment of the forearm and anastomoses with the posterior interosseous artery which continues distally to join the dorsal carpal arch.