Anomalous Distal Branching of the Median Nerve: Case Reports

A rare finding of the median nerve in the forearm

“…A bifid median nerve just proximal to the flexor retinaculum has a reported incidence of 2.8% and is almost always associated with a large persistent median artery (Gutowski et al, 2000;Propeck et al, 2000). More proximally split median nerves have been described (Thompson, 1922;Kessler, 1969;Eiken et al, 1971;Moneim, 1982;Matini, 1983;Kitayama et al, 1985;Amadio, 1987). Baruch and Hass (1977) and Fernandez-Garcia et al (1994) have reported a median nerve that was split by a tendon of the FDS.…”

“…No other anomalies were found. Uncommon deviations of the median nerve in the forearm include the following: it may pass deep to the two heads or pierce the humeral head of the pronator teres muscle; it may split, forming a cleft in the forearm, thus allowing the ulnar artery, the flexor pollicis longus, or palmaris longus muscle to traverse it; and the nerve may lie on the superficial surface of the FDS instead of deep to it (Anson, 1966;Eiken et al, 1971;Crandall and Hamel, 1979;Amadio, 1988;Artico et al, 2000;Bergman et al, 1988;Cavallo et al, 2003). A bifid median nerve just proximal to the flexor retinaculum has a reported incidence of 2.8% and is almost always associated with a large persistent median artery (Gutowski et al, 2000;Propeck et al, 2000).…”

High origin of the third digital branch of the median nerve

“…[11] The high division of the median nerve is an anatomical variation which has been reported in the literature with an incidence of 3%. [1][2][3] Lanz [5] classified variations of the median nerve into four groups: 1) division into a thenar branch; 2) accessory branches of the median nerve in the distal portion of the carpal tunnel; 3) a far proximal division in the nerve track occurring at the level of the forearm; 4) accessory branches that leave the nerve trunk proximal to the carpal tunnel. Lanz reported the incidence of the high division of the median nerve as 2.8%.…”

“…[1][2][3] This variation is often combined with the presence of the median artery. [2,[4][5][6][7] However, high division of the median nerve does not always co-exist with the median artery. A transmuscular course of a median nerve branch in the forearm has also been described in the literature and it has been associated with entrapment neuropathy with symptoms resembling carpal tunnel syndrome.…”

Surgical anatomy of the carpal tunnel

“…The medial nerve may bifurcate in the forearm around a persistent median artery, anomalous lumbrical muscle, or palmaris longus tendon. [11,16,43] An accessory branch of the median nerve may originate proximally, joining the recurrent motor branch or innervating a portion of the thenar musculature by an independent path. [50] Odgen [38] reported a proximal accessory branch of the median nerve that joined the recurrent motor branch distally.…”