ANATOMY

Detailed explanation-1: -The axillary artery commences from the subclavian artery at the outer border of the first rib and terminates when it becomes the brachial artery at the outer border of the teres major muscle.

Detailed explanation-2: -The subclavian arteries course laterally between the anterior and middle scalene muscles. The distal limit of the subclavian artery is the lateral border of the first rib, where it becomes the axillary artery.

Detailed explanation-3: -As the subclavian artery crosses the lateral border of the first rib, it becomes the axillary artery. On the right side the subclavian artery arises from the brachiocephalic (innominate) artery behind the right sternoclavicular articulation; on the left side it springs from the arch of the aorta.

Detailed explanation-4: -Beyond the first rib where it passes underneath the clavicle, the subclavian artery becomes the axillary artery and passes underneath the pectoralis minor muscle.

Detailed explanation-5: -The subclavian artery transitions to the axillary artery at the lateral border of the first rib (Fig. AI2. 11B). The axillary artery then transitions to the brachial artery at the lower border of the teres major muscle.