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 segments, each giving rise to several branches that supply various muscles and tissues in the shoulder and arm. Key branches include the Thoracoacromial Artery and the Subscapular Artery, which play important roles in providing blood to the surrounding areas.