Salpingopharyngeus muscle

The salpingopharyngeus muscle is a muscle of the pharynx. It arises from the lower part of the cartilage of the Eustachian tube,  and inserts into the palatopharyngeus muscle by blending with its posterior fasciculus. It is innervated by vagus nerve (cranial nerve X) via the pharyngeal plexus. It raises the pharynx and larynx during deglutition (swallowing) and laterally draws the pharyngeal walls up. It opens the pharyngeal orifice of the Eustachian tube during swallowing to allow for the equalization of pressure between it and the pharynx.

Structure
The salpingopharyngeus is a very slender muscle.  It passes inferior-ward from its origin to its insertion  within the salpingopharyngeal fold.

Origin
The salpingopharyngeus muscle arises from the inferior portion of the cartilaginous part of the pharyngotympanic tube near its pharyngeal opening. Its origin creates the posterior welt of the torus tubarius.

Insertion
It ends distally by blending with the palatopharyngeus muscle.

Innervation
The salpingopharyngeus receives motor innervation from the pharyngeal plexus of the vagus nerve.

Blood supply
The salpingopharyngeus muscle receives arterial supply from the ascending palatine artery, greater palatine artery, and the pharyngeal branch of the ascending pharyngeal artery.

Variation
The salpingopharyngeus muscle is absent in about 40% of individuals. It is more common in thin individuals.

Function
The salpingopharyngeus muscle raises the pharynx and larynx during deglutition (swallowing) and laterally draws the pharyngeal walls up. Unusually, it is relaxed during deglutition, but contracts at all other times. It opens the pharyngeal orifice of the Eustachian tube during swallowing allowing for the equalization of pressure between the it and the pharynx.