Genioglossus muscle is an extrinsic muscle of tongue which is fan-shaped and creates the most of the volume of the tongue together with its equivalent of the contrasting part.
The genioglossus muscles begin from the superior mental spines at the posterior side of the mandibular symphysis directly superior towards the origin of the geniohyoid muscles through the inferior mental spines.
The fibres spread out backwards fan-wise inside the matter of the equivalent half of the tongue for insertion together with the median septum, from the tip to the base.
- Lower fibres create the root of the tongue and get inserted within the body of the hyoid.
- Intermediate fibres travel under the anterior margin of the hyoglossus and also extend backwards equal to stylohyoid ligament as well as middle constrictor of the pharynx.
- Upper fibres turn upwards and forwards in order to spread out as far as the tip of the tongue.
The genioglossus muscles are supplied by the hypoglossal nerves [XII], similar to majority of muscles of the tongue.
The genioglossus muscles:
- Lower the central portion of the tongue
- Project the anterior portion of the tongue outside the oral fissure or push the tongue outwards.
- Help in swallowing the food by creating a channel towards the GIT.