Glossopharyngeal part of superior pharyngeal constrictor

The glossopharyngeal part of superior pharyngeal constrictor is the lowermost and smallest portion of the superior pharyngeal constrictor muscle that forms part of the lateral wall of the oropharynx near the base of the tongue.

Origin

It arises by a few small muscular slips from the side of the tongue, near the attachment of the palatoglossus and styloglossus muscles. These fibres extend posteriorly and medially from the root of the tongue toward the pharyngeal wall.

Insertion

Fibres pass posteriorly and medially to insert into the median pharyngeal raphe, blending with fibres from the opposite side.

Superiorly, they merge with the mylopharyngeal fibres, while inferiorly, they are continuous with the middle pharyngeal constrictor.

Innervation

Supplied by the pharyngeal branch of the vagus nerve (cranial nerve X) via the pharyngeal plexus, which also receives motor fibs from the cranial part of the accessory nerve (CN XI).

Actions

• Constricts the upper pharyngeal cavity during the early phase of swallowing.

• Coordinates with the tongue muscles (especially the styloglossus and palatoglossus) to direct the food bolus posteriorly and initiate pharyngeal peristalsis.

Clinical correlates

• Dysfunction of this part may contribute to oropharyngeal dysphagia, especially when associated with vagus or glossopharyngeal nerve lesions.

• Medially, the glossopharyngeal part of superior pharyngeal constrictor is covered by pharyngeal mucosa and the lingual tonsil. The glossopharyngeal nerve (CN IX) traverses the gap between the superior and middle pharyngeal constrictors and is vulnerable during tonsillectomies or oropharyngeal surgeries — its injury can cause loss of taste and sensation from the posterior third of the tongue and impaired gag reflex.