54 EQUINE ANATOMY. 



INTERNAL PTERYGOID. 



Origin. — Palatine crest and pterygoid process. 

 , Insertion. — In hollow of maxillary ramus. 

 Action. — Elevates and moves jaw laterally. 

 Nerve. — Inferior maxillary of fifth. 



DIGASTRIC. 



Origin. — Posterior belly from styloid process of occipital bone; 

 tendon passes through fibrous ring of insertion of stylo-hyoideus 

 into hyoid. 



Insertion. — Into posterior border and internal face of inferior 

 maxilla. 



Action. — Raises hyoid bone or depresses lower jaw. 



Nerve. — Facial. 



MYLO- HYOID. 



Origin. — Mylo-hyoid ridge of inferior maxilla. 

 Inse7'tion. — Body of hyoid and anterior appendix and median 

 raphe between two muscles. 



Action. — Same as above and also elevates tongue. 

 Nerve. — Inferior maxillary of fifth. 



GENIO-HYOID. 



Origin. — Genial surface of inferior maxilla. 

 Insertion. — Extremity of hyoideal appendix. 

 Action. — Draws hyoid forward and upward. 

 Nerve. — Hy poglossal. 



STYLO-HYOID. 



Origin. — Superior angle of styloid bone. 



Insertion. — Base of hyoideal cornua. 



Action. — Antagonizes former ; carries hyoid up and back. 



Nerve. — Facial. 



KERATO-HYOID. 



Origin. — Posterior border of styloid cornu and inferior ex- 

 tremity of hyoid bone. 



Insertion. — Superior border of thyroid coinua. 

 Action. — Approximates two cornua. 

 Nerve. — Hypo-glossal. 



