Palatoglossus muscle

Structure

From its origin, it passes anteroinferiorly and laterally. It passes anterior to the palatine tonsil.

Origin

The palatoglossus arises (the oral aspect of) the palatine aponeurosis of the soft palate, where it is continuous with its contralateral partner (i.e. the same muscle of the opposite side).

Insertion

It inserts onto the side of the tongue; some of its fibers extend over the dorsum of the tongue, and some pass into the substance of the tongue to intermingle with the transverse muscle of tongue.

Innervation

The palatoglossus muscle receives motor innervation from the pharyngeal plexus of vagus nerve.

It is the only muscle of the tongue not innervated by the hypoglossal nerve (CN XII).

Controversy

Some sources state that the palatoglossus is innervated by fibers from the cranial part of the accessory nerve (CN XI) that travel via the pharyngeal plexus.

Other sources state that the palatoglossus is not innervated by XI hitchhiking on X, but rather it is innervated by IX via the pharyngeal plexus formed from IX and X.

Actions/movements

The palatoglossus elevates the root of the tongue (i.e. the posterior attached portion of the tongue). It approximates the ipsilateral (same side) palatoglossal arch to the contralateral (opposite side) one, thus separating the oral cavity and the oropharynx.