1- The first part is between the lateral border of the first rib and the superior border of the pectoralis minor muscle.
2- The second part lies deep to the pectoralis minor muscle.
3- The third part extends from the inferior border of the pectoralis minor muscle to the inferior border of the teres major muscle.
First Part of the Axillary Artery
* This part is enclosed in the axillary sheath along with the axillary vein and has only one branch (the 1st part has 1 branch ) the supreme thoracic artery.* This artery helps to supply the first two intercostal spaces and the superior part of the serratus anterior muscle.
Second Part of the Axillary Artery
* This part of the artery lies deep to the pectoralis minor muscle.* The lateral, medial and posterior cords of the brachial plexus are so named respective to this part of the axillary artery.
* This 2nd part of the axillary artery has 2 branches, the thoracoacromial and lateral thoracic arteries.
Third Part of the Axillary Artery
* This part extends from the inferior border of the pectoralis minor muscle to the inferior border of the teres major muscle.* As it is the 3rd part it has 3 branches, the anterior and posterior circumflex humeral arteries and the subscapular artery.
