The (or "Spinal accessory nerve") is the eleventh of twelve
Cranial Nerves . It leaves the cranium through the
Jugular Foramen along with the
Glossopharyngeal Nerve (IX) and
Vagus Nerve (X). It innervates the
Sternocleidomastoid Muscle (sternomastoid) and
Trapezius Muscle on the ipsilateral side.
There are two parts to the accessory nerve:
- A ''spinal part'', that innervates the muscles around the neck.
- A ''cranial part'', that splits off, and quickly combines with the Vagus Nerve . The cranial part of nerve XI can be thought of doing the exact same things as the vagus.
Getting a person to shrug their
Shoulder s while you push down tests trapezius. When a person turns their head, especially against force, sternocleidomastoid should be prominent.
