The anatomic basis of the fascio-cutaneous flap of the posterior interosseous artery.

The authors present a study of the surgical anatomy of the posterior interosseous artery (PIA) in 70 cases to establish the anatomic basis of a new forearm fascio-cutaneous flap, the posterior interosseous flap which has been described by one of the authors (AC Masquelet). The PIA was verified in every case. Its course corresponds to a line drawn from the lateral epicondyle of the humerus to the head of the ulna, i.e. to the septum between the extensor carpi ulnaris and extensor digiti minimi proprius muscles. The artery, whose average caliber is 1.7 mm, gives off 7 to 14 cutaneous branches in its course. The point of emergence of the artery in the posterior aspect of the forearm corresponds to the junction between the upper and middle thirds of the line from the epicondyle and the ulnar head. The PIA anastomoses with the anterior interosseous artery and the dorsal carpal network in 98.6% of cases. The artery remains closely related to the deep branch of the radial nerve and is crossed by the branches of this nerve to the extensor carpi ulnaris muscle. The cutaneous distribution of the PIA extends from elbow to wrist, centered on the epicondylarulnar line, with an average breadth of 5 cm. Twelve operations have already been performed using the posterior interosseous flap, 2 with a direct pedicle and 10 with a retrograde pedicle, and all survived completely.