A previously undescribed case of the axillary arch muscle.

The axillary arch muscle, also called Langer's muscle, axillopectoralis, or pectodorsalis, is a muscular variation of the latissimus dorsi muscle. During a standard anatomical dissection, the axillary arch muscle was found bilaterally. On both sides it originated from the latissimus dorsi as a muscle belly. Next it passed into wide tendinous structure attached to the tendon of the pectoralis major muscle. Then, a narrow tendinous slip inserted into the coracoid process was found. The axillary arch muscle was innervated by the thoracodorsal nerve on both sides. Knowledge about morphological variations in this region is important because there is a direct relationship with neurovascular structures, e.g. ending branches of the brachial plexus, which may lead to paraesthesia or muscle weakness.