Stylopharyngeus muscle

The stylopharyngeus is a muscle in the head that stretches between the styloid process and the pharynx.

Structure
The stylopharyngeus is a long, slender muscle, cylindrical above, flattened below. It arises from the medial side of the base of the styloid process, passes downward along the side of the pharynx between the superior pharyngeal constrictor and the middle pharyngeal constrictor, and spreads out beneath the mucous membrane.

Some of its fibers are lost in the constrictor muscles, while others, joining with the palatopharyngeus muscle, are inserted into the posterior border of the thyroid cartilage.

The glossopharyngeal nerve runs on the lateral side of this muscle, and crosses over it to reach the tongue.

Innervation
This is the only muscle in the pharynx innervated by the glossopharyngeal nerve (CN IX) and is done by its motor branch which supplies special viceral efferent fibers to it.

Actions
The stylopharyngeus:
 * elevates the larynx
 * elevates the pharynx
 * dilates the pharynx to permit the passage of a large food bolus, so facilitating swallowing

Embryological Origin
Third Pharyngeal Arch