This nerve arises from the whole cervical spinal cord, and passes up the neck between the superior and the inferior roots of the cervical spinal nerves. In its course along the neck it gradually becomes thicker by the addition of fresh fibres from the cord, and enters the cranium through the foramen magnum. It receives some fibres from the posterior part of the medulla oblongata, and then, united with the pneumogastric for about an inch of its course, passes out through the foramen lacerum basis cranii. Beyond this point the nerve is directed backward beneath the mastoidodiumeralis muscle, giving branches to the superior cervical ganglion, the sterno-maxillaris, the mastoido-humeralis, and finally terminates in the cervical and dorsal trapezius.

It is a nerve of motion.