The Genioglossus is an extrinsic muscle of the tongue. It arises from the mental spine of the mandible on the inner aspect of the mental symphysis. It fans out to insert into the tongue from the tip to the base. It is innervated by the hypoglossal nerve (CN XII). It protrudes and depresses the tongue.

Paralysis of the genioglossus muscle causes the tongue to fall posteriorly. This presents the risk of airway obstruction and suffocation.