The axillary artery is a major blood vessel that supplies oxygenated blood to the upper limb. It begins at the outer border of the first rib, where it continues from the subclavian artery, and extends to the lower border of the teres major muscle, where it transitions into the brachial artery. This artery is divided into three parts based on its relationship with the pectoralis minor muscle. Each part gives rise to several branches that supply blood to the shoulder, chest, and upper arm, playing a crucial role in the vascular system of the upper body.