Above, it lies upon the rectus capitis lateralis, behind the internal carotid artery and the nerves passing through the jugular foramen.

Lower down, the vein and artery lie upon the same plane, the glossopharyngeal and hypoglossal nerves passing forward between them.

The left vein is generally smaller than the right, and each contains a pair of valves, which exist about 2.5 cm above the termination of the vessel.

Such a line may be inserted for several reasons, such as to accurately measure the central venous pressure or to administer fluids when a line in a peripheral vein would be unsuitable (such as during resuscitation when peripheral veins are hard to locate).

This article incorporates text in the public domain from page 648 of the 20th edition of Gray's Anatomy (1918)