cranial root
Quick Summary
The cranial root is a component of the accessory nerve (CN XI), which originates from the medulla oblongata. Its fibers join the vagus nerve and supply muscles in the pharynx and larynx. For practical purposes, this cranial part is considered part of the vagus nerve.1
The accessory nerve also has a spinal root originating from cervical levels C1–C4. These fibers ascend, enter the cranial cavity through the foramen magnum, and exit via the jugular foramen. The accessory nerve innervates the sternocleidomastoid muscle, enabling head tilting and rotation, and the trapezius muscle, which stabilizes and shrugs the shoulder.1
Cranial nerves are part of the peripheral nervous system and connect the brain to various parts of the body. They can be purely sensory, purely motor, or mixed. The brainstem, which includes the medulla oblongata, contains most cranial nerve nuclei and controls vital involuntary functions like breathing and heart rate.234
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