Origin of the subscapular artery in the South African Black population

Abstract

There is great variability in the branching patterns of the axillary artery (AA). Racial differences have been reported to play a role in this variability. The subscapular artery (SA) is the largest and most variable branch of the AA. It usually arises from the third part of the AA at the inferior border of the subscapularis muscle. Approximately 4 cm from its origin, the SA divides into the circumflex scapular and thoracodorsal arteries. Two types of the SA have been described, depending on the site of its origin from the AA in relation to the point where the AA passes between the lateral and medial roots of the median nerve. It is referred to as the superficial SA (SSA), when proximal, and the deep SA (DSA), when distal to this point, respectively. This study aimed to determine the site and distance of origin of the SA from the outer border of the first rib in the South African Black population. The study comprised bilateral gross anatomical dissections of 50 adult Black South African cadavers (n = 100 AAs). The site and distance of origin of each vessel from the outer border of the first rib were recorded. Additional branches and variations were also noted. The SSA and DSA were found in 52.8% and 47.2% of cases, respectively. In 16.8% of cases, the SA gave rise to the posterior circumflex humeral artery and the lateral thoracic artery in 33.7% cases. The SA was absent in 11% of the cases. The prevalence of the SSA reported in this study differs from values ranging between 1.7% and 16% reported in the literature. The high incidence of the SSA in this study may have clinical significance as a superficial course of the arteries make them vulnerable to injury during surgical procedures.