The axillary arch: anatomy and suggested clinical manifestations

The purpose of this commentary is to describe bilateral anomalous bands of the latissimus dorsi muscle observed in an 81-year-old male embalmed cadaver, and to discuss the possible clinical implications of this anomaly. The musculotendinous bands tautened and compressed the underlying axillary vessels, and the musculocutaneous, median, and ulnar nerves during passive abduction/external rotation of the shoulder. Similar variations found in the latissimus dorsi muscles in this commentary have been reported in the anatomical and surgical literature. These reports include descriptions of the anomalous bands of the latissimus dorsi attaching to the coracoid process, pectoralis major muscle, and fascia of the coracobrachialis muscle. The potential presence of an axillary arch presents several clinical considerations for the physical therapist. The existence of an axillary arch should be considered in patients with signs and symptoms consistent with upper extremity neurovascular compromise similar to thoracic outlet syndrome. Including this variant in the differential diagnostic process may assist physical therapists in the management of patients with signs and symptoms consistent with thoracic outlet syndrome.