Left costocervical vein

The left costocervical vein is a large but short trunk that results from the union of the vertebral, dorsal scapular, deep cervical, and supreme intercostal veins. It begins on the side of the longus colli muscle and then passes laterally to the costocervical artery into the cranial mediastinum. It crosses the left brachiocephalic trunk (ungulates) or the subclavian artery (carnivores) on the left, generally opposite the second intercostal space or the second rib. It ends on the lateral surface of the cranial vena cava or in the left left brachiocephalic trunk.

The costocervical vein is not described in humans, in whom the vertebral, dorsal scapular, deep cervical, and supreme intercostal veins remain separate or have only a very brief common termination in the brachiocephalic vein.