Protrusion of tongue is brought out by:
Genioglossus Muscle:
It is a fan-shaped extrinsic muscle of tongue and along with its counterpart of the opposite side forms the most of the bulk of the tongue 
Origin:
From superior genial tubercle of the mandible.
Insertion:
The fibres radiate backwards fan-wise into the substance of the corresponding half of the tongue alongside the median septum, from the tip to the base, for insertion.

Lower fibres are inserted into the body of the hyoid and form the root of the tongue.
Intermediate fibres pass beneath the anterior border of the hyoglossus and extend backwards up to stylohyoid ligament and middle constrictor of the pharynx.
Upper fibres turn upwards and forwards to extend up to the tip of the tongue.

Nerve supply
It is supplied by hypoglossal nerve.
Actions
The muscles of both sides together protrude the tongue and make an elongated gutter on the dorsal surface of the tongue for the passage of food.
Key Concept:
Genioglossus protrude the tongue and make an elongated gutter on the dorsal surface of the tongue for the passage of food.
Genioglossus
Intrinsic muscles of tongue
Styloglossus
Palatoglossus