Persistent median artery: paedogenesis of the antebrachial arterial system in the human body.

The persistence of the median artery in adult life, a remnant of the early brachial artery in the embryonic stage, has been reported in many anatomical and clinical studies. Herein, we aimed to investigate the prevalence and origin of the median artery in cadavers. We examined 53 adult Japanese cadavers and carefully dissected 106 upper limbs, and the arterial systems in the forearms and hands were observed macroscopically. We found the palmar type of the median artery on 106 sides in 53 cadavers, and found that it passes through the carpal tunnel and forms the superficial palmar arch in the hand in only two cadavers. The antebrachial type, ending in the forearm before reaching the wrist joint, was detected on 63 sides in 44 cadavers. The proportions of the origins of the median artery examined in this study were as follows: originating from the common interosseous artery (CIA) on 15 sides (23%), anterior interosseous artery (AIA) on 9 sides (14%), ulnar artery (UA) on 16 sides (24%), and CIA-UA trunk on 26 sides (39%). None arose from other arteries in the upper limbs. Based on our results and the current theory on vascular development, we conclude that the term 'persistent median artery' must be strictly used for the one that arises from the arteries in the forearm except for the radial artery, and the presence of this ontogenetic remnant can be interpreted as paedogenesis in the human body. We also describe that the increasing trend in the incidence of the median artery since the nineteenth century, as pointed out by a few researchers, may represent 'nearly neutral evolution' at the phenotypic level in human populations.