Describe the segmental anatomy and branches of each segment of the axillary artery

The axillary artery is a major blood vessel that supplies blood to the upper limb and part of the thoracic region. It is divided into three segments by the pectoralis minor muscle, with each segment having its own set of branches.

1. First Segment: This is the part of the axillary artery that is located above the pectoralis minor muscle. It has one branch, the superior thoracic artery, which supplies blood to the upper part of the chest wall and the shoulder.

2. Second Segment: This is the part of the axillary artery that is located behind the pectoralis minor muscle. It has two branches: the thoracoacromial artery, which supplies blood to the acromion and clavicle, and the lateral thoracic artery, which supplies blood to the lateral part of the chest wall and the breast.

3. Third Segment: This is the part of the axillary artery that is located below the pectoralis minor muscle. It has three branches: the subscapular artery, which supplies blood to the scapula and muscles in the back; the anterior circumflex humeral artery, which supplies blood to the humerus and shoulder joint; and the posterior circumflex humeral artery, which also supplies blood to the humerus and shoulder joint.

Each of these segments and their branches play a crucial role in supplying blood to the upper limb and parts of the thoracic region.