C1 spinal nerve

At a glance

Level system

C1 nerve (named for its spinal cord segment)

Where it leaves the canal

The C1 nerve exits between the occiput and the C1 vertebra, above the C1 vertebra.Betts et al. 2022, §13.4

Distance down the canal before it exits

20 mmMeasured on one model: the Visible Human male, imaged as a supine cadaver. Not a normal range; drawn root, schematic

Roots, ganglia and nerves are drawn schematically from each segment to its exit; their paths are not traced from imaging.

What the sources say

“The first nerve, C1, emerges between the first cervical vertebra and the occipital bone.” Betts et al. 2022, §13.4

“All of the spinal nerves are combined sensory and motor axons that separate into two nerve roots.” Betts et al. 2022, §13.4

“The sensory axons enter the spinal cord as the dorsal nerve root.” Betts et al. 2022, §13.4

“The motor fibers, both somatic and autonomic, emerge as the ventral nerve root.” Betts et al. 2022, §13.4

“The cervical plexus is composed of axons from spinal nerves C1 through C5 and branches into nerves in the posterior neck and head, as well as the phrenic nerve , which connects to the diaphragm at the base of the thoracic cavity.” Betts et al. 2022, §13.4