Axillary artery
Arteria axillaris
The axillary artery continues the subclavian artery from the lateral border of the first rib to the inferior border of teres major. Pectoralis minor divides it into three parts, and it runs with the cords of the brachial plexus inside the axillary sheath.
Overview
Pectoralis minor crosses in front of the artery and divides it into three parts. The first part lies above (medial to) the muscle and gives one branch. The second part lies behind the muscle and gives two branches. The third part lies below (lateral to) it and gives three branches.
The cords of the brachial plexus are named by their position around the second part of the artery: lateral, medial and posterior. The median nerve forms in front of the third part, where its lateral and medial roots join in an "M" shape. The axillary vein lies on the medial side of the artery throughout.
The posterior circumflex humeral artery passes with the axillary nerve through the quadrangular space and wraps around the surgical neck of the humerus.
Anatomy
- Branches
First part: the superior thoracic artery. Second part: the thoracoacromial trunk and the lateral thoracic artery. Third part: the subscapular artery (the largest branch, which divides into the circumflex scapular and thoracodorsal arteries), and the anterior and posterior circumflex humeral arteries.
Function
- Supplies the shoulder region, the axillary walls, the lateral chest wall and the breast.
- Continues as the brachial artery to supply the free upper limb.
Clinical significance
Scapular anastomosis
Branches of the subclavian artery (suprascapular and dorsal scapular) join with branches of the axillary artery (circumflex scapular) around the scapula. If the artery must be tied off between the thyrocervical trunk and the subscapular artery, this network keeps blood flowing to the arm.
Injury
The axillary artery can be damaged by anterior dislocation of the shoulder, fractures of the proximal humerus and pressure from crutches. Fracture of the surgical neck of the humerus endangers the posterior circumflex humeral artery and the axillary nerve.
Mnemonics
Branches
"Screw The Lawyer Save A Patient": Superior thoracic; Thoracoacromial, Lateral thoracic; Subscapular, Anterior and Posterior circumflex humeral. The parts give 1, 2 and 3 branches.
Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.