138 HUMAN ANATOMY. 



from a depression in the lower border of the jaw near the sym- 

 physis; the tendon is held to the hyoid bone by an aponeurotic 

 loop and pierces the stylo-hyoid; action, raises the tongue and 

 hyoid bone; nerve, mylo-hyoid branch of the inferior dental and 

 facial. 



STYLO-HYOID. Origin, from outer surface of styloid proc- 

 ess; insertion, into the body of the hyoid bone; action, retracts 

 and elevates the hyoid bone ; nerve, facial : near its insertion it is 

 perforated by the tendon of the digastric. 



MYLO-HYOID. Origin, from the mylo-hyoid ridge of the 

 inferior maxilla from last molar to symphysis; insertion, into a 

 fibrous raphe in the median line, extending from the hyoid bone 

 to the chin and into the body of the hyoid bone; action, draws 

 forward and elevates the hyoid bone and forms part of the floor 

 of the mouth; nerve, mylo-hyoid branch of the inferior dental. 



GTENIO-HYOID. Origin, from inferior genial tubercle of the 

 internal surface of the sjmphysis of the jaw; insertion, into the 

 front of the body of the hyoid bone; action, same as the mylo- 

 hyoid; nerve, hypoglossal. 



MUSCLES OF THE TONGUE. 



GENIO-HYOGLOSSUS. Origin, from superior genial tubercle 

 of the internal surface of the symphysis of the jaw; insertion, 

 by fan-like expansion into the whole length of the inferior sur- 

 face of the tongue, the side of the pharynx, and the body of the 

 hyoid bone; action, retracts and protrudes the tongue; nerve, 

 the hypoglossal. 



HYPOGLOSSUS. Origin, body and greater cornu of the hyoid 

 bone; insertion, between the lingualis and styloglossus into the 

 side of the tongue; action, renders the tongue convex from side 

 to side ; nerve, hypoglossal. 



STYLOGLOSSUS. Origin, from stylomaxillary ligament and 

 styloid process of the temporal; insertion, into the side of the 

 tongue, blending with the hyoglossus and lingualis; action, re- 

 tracts and elevates the tongue; nerve, hypoglossal. 



LINGUALIS. Consists of four portions superficial, inferior, 

 transverse, and vertical. It lies between the genio-hyoglossus 

 and the hyoglossus, extending from the apex to the base of the 

 tongue; action, renders the tgngue convex from before back- 

 ward ; nerve, the chorda tympani. 



PALATO-GLOSSUS (CONSTRICTOR ISTHMI FAUCIUM) (vide PALA- 

 TAL REGION). 



