Subclavian

Subclavian refers to the region beneath the clavicle and to the major vessels and structures that traverse it, including the subclavian artery and subclavian vein. The term also encompasses adjacent nerves, lymphatic vessels, and portions of the brachial plexus and thoracic inlet. The subclavian vessels supply and drain the upper limb and parts of the neck and thorax, and they lie in close relation to the scalene muscles and the first rib.

The subclavian artery originates on the right from the brachiocephalic trunk and on the left from the aortic arch. It passes laterally, posterior to the sternoclavicular joint, and crosses the first rib to become the axillary artery at the lateral border of the first rib. It is commonly described in three parts relative to the anterior scalene muscle: the first part medial to the muscle, the second part behind the muscle, and the third part lateral to the muscle. Branches include from the first part the vertebral artery, internal thoracic (mammary) artery, and thyrocervical trunk; from the second part the costocervical trunk; and from the third part a dorsal scapular artery (variable). The artery supplies the neck, upper chest and shoulder, and contributes to the posterior circulation via the vertebral artery.

The subclavian vein forms at the outer border of the first rib, where the axillary vein continues medially to become the subclavian vein. It runs anterior to the anterior scalene muscle and joins the internal jugular vein behind the sternoclavicular joint to form the brachiocephalic vein. Tributaries include connections from the head, neck, thorax, and upper limb, notably the external jugular vein. The subclavian vein is a common site for central venous access, but puncture carries risks such as pneumothorax and vascular injury.

Lymphatic drainage from the subclavian region includes lymph nodes and trunks that drain into the right lymphatic duct or thoracic duct, reflecting the region’s role in upper-limb and thoracic lymphatics.