Research: Relationship of the Hypoglossal Nerve to C1

Chiropractors have long known about the relationship between facial nerves and the upper cervical spine, so they might find interest in this study.

Published in the World Neurosurgery journal, six cadavers (12 sides) were dissected to carefully explore the small branches of the hypoglossal nerve, and their relationship to the atlanto-occipital joint. Here were the findings:

A small branch was found to always arise from the dorsal aspect of the hypoglossal nerve at the level of the transverse process of the atlas and joined small branches from the first and second cervical nerves. The hypoglossal and C1 nerves formed a nerve plexus, which gave rise to branches to the rectus capitis anterior and rectus capitis lateralis muscles and the atlanto-occipital joint.

– World Neurosurgery, January 18, 2017

It goes without saying that most hypoglossal nerve problems aren’t within the scope of chiropractic care. Stroke, infection, difficulty speaking, or tumors found at the base of the skull are clearly suited for medical professionals.

However, neck injuries do fall within the scope of practice for chiropractors, so pay close attention to problems with chewing or swallowing. When the hypogossal nerve is permanently damaged, the patient’s tongue will atrophy (shrink).

When issues develop involving the hypoglossal nerve (XII), the tongue may become paralyzed. Fortunately there are ways to test the nerve’s function. The first is to instruct patients to stick out their tongue. When a form of paralysis is present, the tongue points in the direction of the affected side.

A second way is to asses the strength of the tongue by asking patients to firmly press it against the inside of their cheek. Doctors will then measure how strongly the patient presses.

This study appears to be unique – authors believe it’s the first description of a branch of the hypoglossal nerve being involved in the innervation of C0-C1.