Medical Speech Pathology

Curiosity, Dialogue, and Knowledge

Oral tongue vs. Base of Tongue in Normal Swallow Function


a sagittal view of the head and neck with a line bisecting the oral and base of tongue

picture provided by Dr. Jeri Logemann

Oral Tongue vs. Base of Tongue in Normal Swallow Function

 Jerilyn A. Logemann, Ph.D., CCC-SLP, BRS-S

The oral tongue receives neural control from the cortex and the 12th cranial nerve (Hypoglossal). The oral tongue is under voluntary control and is responsible for manipulating food in the mouth for chewing and sensing volume and viscosity. When the oral tongue has completed chewing, it will subdivide the food into a swallowable bolus depending on viscosity and sequester any remaining food in the cheek pouch. Then the oral tongue initiates the oral stage of swallow by sealing the sides of the tongue against lateral and anterior alveolar ridge and sequentially squeezing the bolus backwards through the mouth by the upward movement of the midline of the oral tongue. Pressure from the oral tongue is always against the tail of the bolus/food. As the oral tongue propels the bolus back, sensory information is sent to the medulla to trigger the pharyngeal stage of swallow.

The pharyngeal stage of swallow includes velopharyngeal closure to prevent the food from going up to the nose, airway closure to prevent aspiration, and laryngeal and hyoid upward and forward motion which yanks the upper esophageal sphincter open. When the tail of the bolus reaches the base of tongue which is under medullary control via the 10th cranial nerve (Vagus), the pressure generation against the food through the pharynx is the result of tongue base posterior movement to touch the inward moving posterior pharyngeal wall and lateral pharyngeal walls. Thus, the combination of oral tongue propulsion through the mouth and base of tongue propulsion through the pharynx drives the bolus into the esophagus. The clearance of the valleculae is the result of tongue base backward movement. The tongue base should make complete contact with the posterior pharyngeal wall or there will be residue remaining in the valleculae after the swallow. This is true in both adults and children.

If a patient with dysphagia exhibits residue in the valleculae, then tongue base exercises are needed including the effortful swallow, the range of motion tongue base exercises including pulling the tongue straight back as far as possible and holding for a few seconds, starting a yawn and holding the posterior position of the tongue for a few seconds and pretending to gargle and holding the posterior tongue position for the gargle for several seconds.

REFERENCES

Logemann, J. A. (1998). Evaluation and treatment of swallowing disorders (2nd ed.).

Austin, TX: ProEd.

Veis, S., Logemann, J. A., and Colangelo, L. A. (2000). Effects of three techniques on

maximum posterior movement of tongue base. Dysphagia, 15, 142-145.

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