The Head and Neck. 243 



7. Dissection of the tongue and hyoid : 



The mylohyoideus should be reflected. Note the position of the 

 lingual nerve. 



(a) The stylohyoideus major muscle. Origin : Jugular process 

 of the occipital bone. Insertion: Tip of the greater cornu 

 of the hyoid. The muscle has been divided. 



The superficial temporal and internal maxillary arteries should be 

 divided. 



(b) The styloglossus. Origin: Jugular process. Insertion: 

 The muscle passes downward and forward, expanding at the 

 base of the tongue into a broad sheet, the fibres of which 

 extend to its anterior tip. 



The muscle should be carefully separated from two others on its 

 dorsomedial side and divided. 



(c) The stylohyoideus minor. Origin: Jugular process. In- 

 sertion: Lesser cornu of the hyoid. A slender muscle hav- 

 ing about the same direction, but ending on the more dorsal 

 part of the hyoid apparatus. 



The remaining muscle is the stylopharyngeus, a thin delicate 

 muscle, the insertion of which is on the lateral wall of the pharynx. 



(d) The geniohyoideus. Origin: Mandibular symphysis. In- 

 sertion: Anterior surface of the body of the hyoid: unpaired. 



(e) The genioglossus. Origin: Medial surface of the man- 

 dible immediately behind the symphysis. The fibres pass 

 upward and slightly backward into the substance of the 

 tongue. 



(f) The hyoglossus. Origin: The body of the hyoid and the 

 greater and lesser cornua by more or less separate heads. 

 The muscle passes into the base of the tongue, enclosed on 

 either side by the styloglossi. 



(g) The lingualis, or intrinsic muscle of the tongue consists of a 

 mass of fibres with no skeletal attachments. 



(h) The lingual nerve (n. lingualis), one of the chief branches 

 of the mandibular, passes forward and downward to the 

 side of the tongue and enters its substance immediately 

 below the ventral border of the styloglossus. 



The lingual is the sensory nerve of the tongue. Near its point of 

 origin the lingual nerve receives the chorda tympani (p. 254). 



