Unusual variations of the vasculonervous elements of the human axilla. Report of three cases.

Three cases of multiple anomalies involving the vessels and nerves of the axilla are reported. The main common characteristic between them was the unilateral existence of a superficial brachial artery. The other arterial variations encountered were mostly represented by an assembling of some of the usual branches of the axillary artery in a common trunk which we called thoracdorso-subscapular trunk. In two cases, this trunk gave rise to the posterior circumflex humeral artery. Several nervous anomalies accompanied these atypical vascular patterns. The medial fasciculus of the brachial plexus was absent in one subject and an aberrant course of the brachial artery through the median loop was then observed. The two other cadavers showed variations in the distribution of the intermediate trunk and lateral fasciculus of the plexus. Embryologically, the persistence of various segmental arteries in the axilla seems to be responsible for the described anomalies. Otherwise, the present study indicates that the segmental origin of the axillary artery and its pattern of branching may determine the arrangement of the brachial plexus during the fetal development.