MUSCLES OF THE HYOID REGION 313 



Origin. — From the inner face of the lower jaw behiml the iiidlar 

 teeth. 



Insertion. — From the point of origin its fibres pass under the tongue 

 and meet those of the muscle from the opposite side iu the centre, where 

 they blend together. Behind they are inserted into the spur-like pi'ojection 

 of the tongue bone. 



Action. — This muscle lifts the tongue towards the palate, and assists in 

 mastication and swallowino-. 



Genio-Hyoideus. — This is a long, narrow muscle, with tapering ex- 

 tremities, situated beneath the tongue. 



Origin. — P\'om the lower jaw, near the symphysis or joining of the two 

 branches. 



Insertion. — Into the spur-process of the hyoid or tongue ]>one. 



Action. — To draw the hyoid bone forward and assist in protruding the 

 tongue. 



Stylo-Hyoid. — Situated in the region of the throat. 



Origin. — From the superior and posterior part of the long cornu of the 

 hyoid or tongue bone. 



Insertion. — Into the outer part of the heel-like process of the same 

 bone, where its tendon divides to allow the middle tendon of the digastricus 

 to pass between its branches. 



Action. — To draw the larynx and the tongue backwards and upwards. 



Hyoideus Transversus. — This is a small single muscle placed between 

 the two small cornua of the tongue bone. It is attached to the inner 

 surface of each, and crosses over from one side to the other. 



Action. — To maintain the small cornu in position during the various 

 movements of the tongue. 



KeratO-Hyoid. — A small, flat, triangular muscle situated at the root of 

 the tongue. 



Oi-igin. — From the posterior border of the lower end of the long cornu, 

 and from the posterior border of the small cornu. 



Insertion. — Into the upper border of the heel process of the tongue 

 bone. 



Action. — To raise the heel process and elevate the larynx. 



The Digastricus. — This is composed of two small muscular masses 

 united l)y 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 lione. The tendon intervening between the two bellies plays 

 through a division above referred to iu the tendon of another muscle (stylo- 

 hyoid) against the tongue bone. 



