The Vagus Nerve and Ankyloglossia
The “vagus nerve contains 75% of the parasympathetic nervous system’s fibers.” (1) “Vagal tone is correlated with the capacity to regulate stress” (2) It is the nerve of “rest and digest”
“Compression or traction of the fascial sleeve of the vagus nerve, can result in an alteration in vagal “tone“or autonomic dysfunction.” (3)
The vagus nerve is both the longest and most complex of all the cranial nerves. It is comprised of both efferent (motor) and afferent (sensory) fibers. The vagus nerve carries signals to the heart and the digestive systems from the brain and back again.
In the oral space the efferent fibers (motor) innervate the muscles of mastication. The afferent fibers (sensory)innervate the palate and the epiglottis.
The vagus nerve originates in the medulla oblongata and exits though the jugular foreman. The jugular foramen lies between the between the jugular fossa of the petrous part of the temporal bone and the jugular process of the occipital bone. (Figure#1) The vagus is joined both by the accessory and the hypoglossal nerve. The vagus nerve lies between the other two. Movement of either the temporal bones or the occipital bone can cause changes in the shape of the jugular foramen which would cause tension on cranial nerves within. When there is ankyloglossia, tension on the styloid process from the styloglossus muscles pulls on all of the cranial bones commencing with the temporal and occiput. (Figure #2, 3) For those working with infants and children, the lateral parts of the occiput where we find the jugular foreman (Figure#4) is in two pieces and does not fuse until roughly 4-6 years of age. (4) Therefore, this a place where there maybe tension on the fascial sleeve of the nerves if the bones are out of alignment which can occur easily.
Figure 1. Jugular Foreman 
Figure 2. Styloid Process 
Figure 3. Skull 
Figure 4. Infant Occiput
The vagus nerve provides motor innervation to the palatoglossus muscle. (5) In ankyloglossia, the palatoglossus is under tension. This will then strain the vagus nerve potentially disrupting its functioning.
Gil Hedley, (6) shared in his Nerve Tour presentation a visual where the hypoglossal and vegus nerve merge. When I reached out to him to discuss this he shared that there is significant cross connection at the foramina between the hypoglossal and the vagus nerves. The hypoglossal provides motor and sensory to eight of the nine muscles of the tongue. When the tongue is restricted in its range of motion there maybe strain on the innervation.
Vagus nerve damage is known to lead to gastroparesis – food not moving into your intestines. The vagus nerve damage is also known to cause difficulty swallowing and gastroesophageal reflux. Both of these are seen in infants/children and adults with ankyloglossia.
I contend, and it is my theory, based on my experience working with infants, children and adult with ankyloglossia. Adding the experiences that adults with ankyloglossia have shared that the sympathetic nervous system is activated.
If you are “struggling to eat, possibly having difficulty swallowing and often there is greater exertion needed to breathe – I ask you with these challenges would your sympathetic nervous system be engaged?” (7)
If the vagus nerve is compromised it is unable to down regulate the sympathetic nervous system leaving the system in a constant state of “fight or flight”.
References:
- Cleveland Clinic (2022) https://my.clevelandclinic.org/health/body/22279-vagus-nerve
- Breit, S Kupferberg, A (2018) Vagus Nerve as a Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders. Front Psychiatry https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2018.00044/full
- Vallone, S (2016) Evaluation and Treatment of Breastfeeding Difficulties Associated with Cervicocranial Dysfunction: A Chiropractic Perspective J Clin Chiro Ped 15(3) 130
- Crelin, E. (1973) Functional Anatomy of The Newborn. Yale University Press.
- Mu, l Chen, J et al. (2021) Innervation of the human soft palate muscles. The Anatomical Record https://anatomypubs.onlinelibrary.wiley.com/doi/full/10.1002/ar.24531
- Hedley, G. (2025) The Nerve Tour https://www.gilhedley.com
- Berg, P. (2025) The Benefits of CranioSacral Therapy for the person with Ankyloglossia. American Laser Study Club.
