Median artery of the forearm in human fetuses in northeastern Brazil: anatomical study and review of the literature.

A persistent median artery is a rare anomaly. It accompanies the median nerve along its course in the forearm and is of variable origin. It is associated with other local anatomical variations and may contribute significantly towards formation of the superficial palmar arch. In embryos, it is responsible mainly for the blood supply to the hand. The objective of this study was to research the frequency, type (forearm or palmar) and origin of the median artery in fetuses, correlating its presence with sex and body side. Red-colored latex was injected into 32 brachial arteries of human fetuses until its arrival in the hand could be seen. Twenty-four hours after the injection, the median arteries were dissected without the aid of optical instruments. Among the 32 forearms dissected, the median artery was present in 81.25 % (26) of the cases, and it was found more frequently in females and on the left side. Regarding origin, most of the median arteries originated in the common interosseous artery (38.5 %) and anterior interosseous artery (34.6 %). The mean length of the median arteries was 21.1 mm for the palmar type and 19.8 mm for the forearm type. The median artery has a high rate of persistence. It is important to be aware of this anatomical variation, since its presence may give rise to difficulties during routine surgical procedures on the wrist. Its presence may cause serious functional complications in the carpal tunnel, anterior interosseous nerve, round pronator syndromes, and ischemia of the hand.