The left brachiocephalic vein is one of the great veins within the superior mediastinum. It is formed from the union of left subclavian vein and left internal jugular vein and so it drains the territories of the left arm and left side of the head and neck respectively.
The left brachiocephalic vein:
- originates deep to the left sternoclavicular joint as the confluence of left internal jugular vein and left subclavian vein
- passes to the right and slightly inferiorly to join with the right brachiocephalic vein deep to the right first costal cartilage; by merging, the two brachiocephalic veins form the superior vena cava
- anteriorly: thymus separating left brachiocephalic vein from sternum, attachments of sternohyoid and sternothyroid muscles
- right: right brachiocephalic vein
- posteriorly, from left to right: left vagus nerve, left common carotid artery, trachea, right brachiocephalic arterial trunk
- left: left apical pleura, left first rib
- superiorly: inferior thyroid veins branches
- inferiorly, from lateral to medial: internal thoracic veins, thymic veins
Apart from the confluence of left subclavian and internal jugular veins, the left brachiocephalic vein also receives the:
- inferior thyroid veins: join superiorly at mid-point and drain thyroid gland
- thoracic duct
- inferior thymic veins: drain the thymus
- superior intercostal vein
The left brachiocephalic vein extends into the neck in infants, so making tracheostomy inadvisable.