Axillary artery

At a glance

English

Axillary artery

Latin (TA2)

Arteria axillaris

System

Artery

Region

Trunk

Side

Paired, left and right

About the axillary artery

The axillary artery carries blood from the root of the neck into the upper limb. It begins at the lateral border of the first rib as the continuation of the subclavian artery, crosses the axilla, and at the lower border of teres major takes the name brachial artery. Along the way it supplies the shoulder region, the side of the chest wall and the axilla itself.

Pectoralis minor crosses in front of the artery and is used to divide it into three parts. The first part lies above (medial to) the muscle, the second directly behind it, and the third below (lateral to) it. Throughout its length the axillary vein lies on its medial side, and the whole bundle is wrapped in the axillary sheath, an extension of the deep cervical fascia. The cords of the brachial plexus are named from their position around the second part: the lateral cord lies on its outer side, the medial cord on its inner side and the posterior cord behind it. Beyond pectoralis minor the cords give way to the terminal nerves, which surround the third part.

Each part gives a set number of branches, one for the first, two for the second and three for the third. The first part gives the small superior thoracic artery to the upper intercostal spaces. The second gives the thoraco-acromial artery, which pierces the clavipectoral fascia and splits into pectoral, acromial, clavicular and deltoid branches, and the lateral thoracic artery, which runs along the lower border of pectoralis minor on the side of the chest. The third gives the subscapular artery, its largest branch, which divides into the circumflex scapular and thoracodorsal arteries, and the anterior and posterior circumflex humeral arteries, which ring the surgical neck of the humerus. The exact pattern of origin varies widely.

Because the subscapular branch joins the scapular anastomosis, the artery can be tied above that branch with the arm still kept alive through collateral flow, but not below it. Shoulder dislocation and fractures of the upper humerus can damage the third part. Surgeons frequently connect the heart-lung machine through the right axillary artery when repairing the aortic arch or ascending aorta.

Course and supply

Arises from

Continues from the subclavian artery at the lateral border of the first rib.

Ends in

Becomes the brachial artery at the lower border of teres major.

Supplies

Supplies the upper chest wall, pectoral muscles, shoulder region, scapular muscles and the upper humerus, and carries the whole arterial supply onward to the arm.