Pterygopharyngeal part of superior pharyngeal constrictor

The pterygopharyngeal part of superior pharyngeal constrictor is the uppermost portion of the superior pharyngeal constrictor muscle.

Origin

• Arises from the lower third of the posterior border of the medial pterygoid plate of the sphenoid bone and the pterygoid hamulus.

• These fibres pass posteriorly and medially, forming an arch beneath the auditory (pharyngotympanic) tube and the levator veli palatini muscle.

Insertion

• Fibres curve backward to insert into the median pharyngeal raphe, blending with fibres from the opposite side.

• The most superior fibres reach the pharyngeal tubercle of the occipital bone

Innervation

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

Action

Narrows the nasopharyngeal lumen during the initial stage of swallowing.

Clinical Relevance

• Dysfunction of the pterygopharyngeal part of superior pharyngeal constrictor may result in velopharyngeal insufficiency, causing nasal regurgitation and hypernasal speech.

• Its close relationship to the sinus of Morgagni (the gap between the muscle’s upper border and the base of the skull) is clinically significant, as this region transmits structures such as the auditory tube, levator veli palatini muscle, and ascending palatine artery.