The structure indicated is the genioglossus muscle of the tongue.

The genioglossus muscle is one of the extrinsic muscles of the tongue. The muscles involved with the tongue consist of intrinsic muscles which lie within the tongue itself, and the extrinsic muscles which attach to the tongue and are responsible for depression, elevation, protraction and retraction of the tongue.

There are four sets of extrinsic tongue muscles:

1. Genioglossus
2. Hyoglossus
3. Palatoglossus
4. Styloglossus

The genioglossus is a large muscle which extends anteriorly from the chin, to the tongue. The genioglossus is involved in depression and protrusion of the tongue.

Origin: Superior mental tubercles

Insertion: Body of hyoid bone and dorsum of tongue

Action: Protrusion and depression of tongue

Innervation:  Hypoglossal nerve (Cranial nerve XII)

Learn all about the anatomy of the cranial nerves and the extrinsic muscles of the tongue and hyoid bone.