Axillary artery

Axillary artery , a. Axillaris, lies in the armpit. It is a direct continuation of the subclavian artery and is located along the clavicle with the subclavian muscle lying under it to the lower edge of the large pectoral muscle, where it continues into the brachial artery, as well. Brachialis.

The axillary artery is conventionally divided along the anterior wall of the axillary cavity into three parts: the first part corresponds to the level of the clavicle-thoracic triangle, trigonum clavipectorale (from the clavicle to the upper edge of the small pectoral muscle), the second part to the level of the small pectoral muscle; The third part extends from the lower edge of the small pectoral muscle to the lower edge of the large pectoral muscle.

The first part of the axillary artery lies on the upper teeth of the anterior dentate muscle, being covered in front by the clavicle-thoracic fascia. The subclavian vein lies in front and inside of the artery, v. Subclavia, anterior and outer - trunks of the brachial plexus, plexus brachialis.

From this part of the axillary artery the following branches branch out.

1. Upper thoracic artery, a. Thoracica superior, begins at the lower edge of the clavicle, is directed downward and medially, sending branches to the two upper intercostal muscles and the anterior dentate muscle, as well as to the large and small pectoral muscles and the mammary gland.

2. The pectoral artery, a. Thoracoacromialis, begins at the upper medial edge of the small pectoral muscle and, perforating from the depth to the surface of the clavicle-thoracic fascia, is immediately divided into the following branches:

A) an acromial branch, r. Acromialis, goes up and out, passes under the large thoracic and deltoid muscles and blood supply them. Having reached the acromion, sends branches to the shoulder joint and, anastomosing with branches a. Suprascapularis and other arteries, takes part in the formation of a vascular acromial network;

B) clavicular branch, r. Clavicularis, is directed to the area of ​​the clavicle; Blood supply to the subclavian muscle;

C) deltoid branch, r. Deltoideus, goes down and out, passes in the furrow between the deltoid muscle and the large pectoral muscle and blood supply these muscles;

D) thoracic branches, rr. Pectorales, follow mainly to the large and small pectoral muscles, partly to the anterior cog muscle.
The second part of the axillary artery lies directly behind the small pectoral muscle and is surrounded by posterior, medial and lateral trunks of the brachial plexus. From this part only one branch leaves - the lateral thoracic artery.

Lateral thoracic artery, a. Thoracica lateralis, from the lower periphery of the axillary artery goes down, passes first behind the small pectoral muscle, and then along its outer edge on the outer surface of the anterior dentate muscle.

Blood supply to the lymph nodes and fiber of the axillary cavity, as well as the anterior dentate muscle, small pectoralis muscle, the mammary gland (lateral branches of the mammary gland, r. Mammarii laterales) and anastomoses with aa. Intercostales and rr. Pectorales a. Thoracoacromialis.

The third part of the axillary artery lies behind the large pectoral muscle, the scapula and the tendons of the broad back muscle and the large round muscle; Outside the artery there is a beak-brachial muscle. Branches of the brachial plexus are located on the sides and in front of this part of the axillary artery.

From the third part of the axillary artery the following branches branch out.

1. Subclavian artery, a. Subscapularis, begins at the level of the lower edge of the subscapular muscle and, going down, is divided into two branches. Before the division begins, the artery gives up two to three small subscapular branches, rr. Subscapulares, which also can depart from the initial part of the artery enveloping the scapula, and terminate in the subscapular muscle.

The terminal branches of the subscapular artery:

A) the artery surrounding the scapula, a. Circumflexa scapulae, goes back and, bending the lateral edge of the scapula, is directed upwards, into the cavity fossa. Blood supply to the subscapular, large and small round muscles, the widest muscle of the back, deltoid and cavity muscles. Forms anastomoses with branches a. Transversa cervicis and a. Suprascapularis;

B) chest cavity artery, a. Thoracodorsalis, continues the direction of the trunk of the subscapular artery. It goes down along the back wall of the axillary cavity along the lateral edge of the scapula in the gap between the scapular muscle, the latissimus muscle of the back and the large round muscle to the lower angle of the scapula. Ending in the thickness of the latissimus muscle of the back, anastomoses with branches a. Transversa cervicis.

2. Anterior artery circumscribing the humerus, a. Circumflexa humeri anterior, begins from the outside of the axillary artery, goes laterally under the beak-brachial muscle, and then under the short head of the biceps arm muscle along the anterior surface of the humerus. Having reached the area of ​​the intercampoon groove, it divides into two branches: one of them occupies an ascending direction, accompanies the tendon of the long head of the biceps brachialis muscle and, having entered the shoulder joint, goes to the head of the humerus; The other branch curves around the outer edge of the humerus and anastomizes with a. Circumflexa humeri posterior.

3. Posterior artery circumscribing the humerus, a. Circumflexa humeri posterior, departs from the back of the axillary artery next to a. Circumflexa humeri anterior. It is directed backwards, rounds the posterior and outer surfaces of the surgical neck of the humerus, aligned with the axillary nerve, n. Axillaris, on the inner surface of the deltoid muscle. Anastomoses with a. Circumflexa humeri anterior, a. Circumflexa scapulae, a. Thoracodorsalis and a. Suprascapularis. Blood supply to the joint capsule of the shoulder joint, deltoid muscle and skin of this area.