Subclavian Vein

Description

Running beneath the clavicle at the thoracic inlet, the subclavian vein is shown coursing lateral to medial as the direct continuation of the axillary vein, lying anterior to the anterior scalene (scalenus anterior) and superficial to the first rib. Medially it approaches the venous angle, where it meets the internal jugular vein to form the brachiocephalic vein, while the sternocleidomastoid sits anterolaterally as a dominant surface landmark. Posterior and slightly superior to the vein, the subclavian artery tracks on the opposite side of the anterior scalene, and the roots and trunks of the brachial plexus emerge between the anterior and middle scalene muscles. Bone landmarks include the clavicle and adjacent scapular elements framing the superior thorax. Anterior scalene is the key divider here. It separates subclavian vein from subclavian artery, and that relationship drives both procedural safety and exam questions because a needle or catheter advanced too deep or too posterior risks arterial puncture or brachial plexus injury. The figure also supports discussion of venous obstruction at the costoclavicular space, where catheter-related thrombosis or thoracic outlet syndrome can compromise subclavian venous return and produce upper limb swelling and collateral venous patterns over the shoulder girdle. Educators will find this composition well suited for teaching the root of the neck in gross anatomy, surface anatomy, and anesthesia modules that cover infraclavicular vascular access and regional blocks. It also fits surgical and interventional radiology content that contrasts subclavian versus internal jugular central venous catheter routes and their complication profiles, including pneumothorax risk near the cupola of the pleura. Anatomical accuracy verified by SciePro's Medical Advisory Board.