C3 spinal nerve

Nervus spinalis C3

NervousNervesNeckLeft and right

View left in 3D View right in 3D

What it is
The C3 spinal nerve leaves the spinal canal between C2 and C3. Its sensory (dorsal) and motor (ventral) roots meet just beyond the dorsal root ganglion; the short mixed nerve then splits into a small dorsal ramus for the back muscles and skin and a larger ventral ramus, which joins the cervical plexus.
Function
Carries motor fibres to the muscles of its segment (myotome) and sensation back from its strip of skin (dermatome): the upper neck and the skin over the angle of the jaw.
Size
About 2-3 mm thick; the mixed nerve is only ~1 cm long before it divides
Clinical note
"C3, 4 and 5 keep the diaphragm alive": a spinal-cord injury above C3 stops breathing because the phrenic nerve is cut off.

Nearby nervous structures C2 spinal nerve, C4 spinal nerve, C5 spinal nerve, C6 dorsal root ganglion, C6 spinal nerve, C7 spinal nerve, C8 spinal nerve