Styloglossus: origin, insertion, nerve, and how it differs from the stylohyoid

Where is the styloglossus?

Styloglossus, stylohyoid, stylopharyngeus: three muscles from the same small spike of bone, easy to mix up before an exam. The second half of each name tells you where it goes, and the styloglossus goes to the tongue.

It starts at the styloid process, a thin, needle-like projection pointing down from the temporal bone deep below the earlobe. From there it runs forward and down to enter the side of the tongue near the back. In this view the right mandible is hidden; with the mandible in place the muscle lies inside the ramus and cannot be seen or felt from the surface.

Origin, insertion and nerve

Inside the tongue its fibres split: some run forward along the edge of the tongue, others interlace with the hyoglossus. Textbooks describe the insertion with different extents, from the tip to the side and dorsum of the tongue.

Its role among the extrinsic tongue muscles

Intrinsic tongue muscles lie entirely within the tongue and change its shape; extrinsic muscles arise from bone outside it and move it. The genioglossus arises from the front of the mandible and pushes the tongue forward; the hyoglossus arises from the hyoid and pulls it down; the styloglossus arises up and behind and pulls it up and back, as when the back of the tongue rises to push food toward the throat during swallowing.

Textbooks count the extrinsic muscles differently. Some list three; others add the palatoglossus to make four. The palatoglossus is the only one supplied by the vagus nerve (pharyngeal plexus) rather than the hypoglossal, so it is sometimes grouped with the palate muscles. The teamLabBody description lists three.

Three muscles from the styloid process

Each nerve matches the region it serves: the hypoglossal for the tongue, the glossopharyngeal for the pharynx. The stylohyoid is the odd one out, supplied by the facial nerve like the posterior belly of the digastric.

Name and terms

Stylo- refers to the styloid process, and -glossus comes from the Greek glossa, tongue. The stylohyoid and stylopharyngeus share the same prefix. The Latin is musculus styloglossus.

See it in the app

The styloglossus is hidden inside the mandible and is often drawn as a single line in side views. In the 3D anatomy app teamLabBody you can hide the mandible and follow it from the styloid process to the tongue, then add the other extrinsic muscles and the stylohyoid to compare where each one enters. Cross sections are available with the PREMIUM plan.

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