The axillary artery, the continuation of the subclavian, commences at the outer border of the first rib, and ends at the lower border of the tendon of the Teres major, where it takes the name of brachial.
Its direction varies with the position of the limb; thus the vessel is nearly straight when the arm is directed at right angles with the trunk, concave upward when the arm is elevated above this, and convex upward and lateralward when the arm lies by the side. At its origin the artery is very deeply situated, but near its termination is superficial, being covered only by the skin and fascia.
To facilitate the description of the vessel it is divided into three portions; the first part lies above, the second behind, and the third below the Pectoralis minor:
The branches are: