Unilateral and Bilateral Axillary Arches in Male and Female Cadavers

Among sixteen donors (32 axillae) dissected in our gross anatomy lab, axillary arch was incidentally observed in three cases (five axillae). In three cases, the axillary arch was observed in five axillae-bilateral in one male and one female donor, and unilateral in one male donor. In all the three cases, the five arches consisted of muscular and connective tissue (aponeurotic/tendinous) parts. The muscular parts originated as slips from the lateral borders of the latissimus dorsi muscles and their connective tissue parts ascended and crossed anterior to the axillary neurovascular bundles to attach to various non-osseus structures on the proximal aspects of the arms. This created a canal dorsal to the axillary arch (designated here as axillobrachial canal or ABC) through which the axillary neurovascular bundles ran to enter the proximal aspect of the arms. The presence of such variant fibromuscular slip can be a cause of neurovascular compression syndrome of the upper limb and may complicate surgical procedures in the axillary region. Therefore, it should be considered in the differential diagnosis of neurovascular compression syndromes of the upper limb and axillary mass to avoid misdiagnosis and unintended damage or injury causing complications.