Axillay artery, a continuation of the subclavian artery, begins at the lateral border of the first rib. At the lower border of the teres major muscle, the axillary artery becomes the brachial artery. The axillary artery is closely related to the brachial plexus in the axillary sheath. The axillary sheath is derived from the prevertebral fascia.
Grey’s Anatomy 20th edition
The axillary artery is divided into three parts by the pectoralis minor muscle.
First Part of the Axillary Artery:
The first part of axillary artery extends between the lateral border of the first rib (the origin of artery) and the upper border of pectoralis minor muscle.
Relations of the First Part:
Anteriorly:
Skin and the pectoralis major muscles. Artery is crossed by the brachiocephalic vein.
Posteriorly:
Long thoracic nerve supplying the serratus anterior muscle.
Medially:
Axillary vein
Laterally:
Cords of brachial plexus
Branches:
The highest thoracic artery arises from the first part moving along the upper border of pectoralis minor muscle.
Second Part of Axillary Artery:
The second part of axillary artery lies behind the pectoralis minor muscle.
Relations of Second Part:
Anteriorly:
Skin, pectoralis major and minor.
Posteriorly:
Shoulder joint, subscapularis and posterior cord of brachial plexus.
Medially:
Axillary vein and medial cord of brachial plexus.
Laterally:
Lateral cord of brachial plexus.
Branches:
1. Thoracoacromial artery dividing into terminal branches.
2. Lateral thoracic artery, moving along the lower border of pectoralis minor.
Grey’s Anatomy 20th edition
Third Part of Axillary Artery:
The third part of axillary artery lies between the lower border of pectoralis minor and the lower border of teres major muscles.
Relations:
Anteriorly:
Medial root of median nerve crosses the artery and pectoralis major is located along its upper part.
Posteriorly:
Axillary nerve, radial nerve, teres major, latissimus dorsi and subscapularis
Medially:
Medial cutaneous nerve of arm, axillary vein and ulnar nerve.
Laterally:
Humerus, coracobrachialis, biceps, musculocuteneous nerve and lateral root of median nerve.
Branches:
1. Subscapular artery, running along the lower border of subscapularis.
2. Anterior circumflex humeral artery, winding along the front of surgical neck of humerus.
3. Posterior circumflex humeral artery, winding along the back of surgical neck of humerus.
Grey’s Anatomy 20th edition
Gosh… I really like what am seeing here.