Axillary Arch

Axillary arch
Axillary arch highlighted in red.
Axillary arch labelled as 'achselbogen'.
Details
Origin	Latissimus dorsi muscle
Insertion	Humerus, Pectoralis major
Artery	Lateral thoracic artery and subscapular artery
Nerve	Lateral pectoral nerve
Latin	Arcus axillaris
Anatomical terms of muscle []

The axillary arch (/ækˈsɪləriː ɑːtʃ/) is a variant of the latissimus dorsi muscle in humans. It is found as a slip of muscle or fascia extending between the latissimus dorsi muscle and the pectoralis major. There is considerable variation in the exact position of its origin and insertions as well as its blood and nerve supply. Its presence in different ethnic groups varies, being present in about 7% of Europeans and with higher rates in the Chinese and less common in the Turkish population. The arch may occur on one or both sides of the body.

The arch is considered to have no functional significance, although this is challenged by some authors. It plays a role in entrapment of nearby structures and may alter local anatomy in the event that a dissection of the local area is needed during surgery. The arch appears to arise from the panniculus carnosus, a structure found in most non-primate mammals, and has similarities with muscles found in many animals. The axillary arch has several other names including Langer's axillary arch, the muscle of Langer, axillopectoral muscle, Achselbogen and pectorodorsalis muscle.

The axillary arch is an arch-shaped anatomical variant of the latissimus dorsi muscle of the human back. Its shape varies, but its defining characteristics are its origin from the latissimus dorsi muscle, its insertion close to or on the upper part of the humerus, and that it crosses the neurovascular bundle associated with the axillary nerve from dorsomedial to ventrolateral. Its size may vary from 7 to 10 cm (2.8 to 3.9 in) in length and 5–15 mm (0.2–0.6 in) in width. The axillary arch may be seen when the arm is abducted and the palms put on the back of the head. An impression can be seen on the medial side of the axilla.