This is composed of two small muscular masses united by a short tendon; hence it is called digastric or a double-bellied muscle.

Origin. - With the stylo-maxillaris from the styloid process of the occipital bone. The tendon intervening between the two bellies plays through a division above referred to in the tendon of another muscle (stylohyoid) against the tongue bone.

Insertion. - The second belly is inserted into the posterior border of the lower jaw behind the chin.

Action. - To raise the hyoid bone and assist in opening the mouth.