308 ANATOMY OF THE RABBIT 



The remaining muscle is the stylopharyngeus, a thin deHcate 

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



In man, the tendon joining the two portions of the digastric muscle 

 usually passes through the stylohyoid muscle. In the rabbit, the 

 tendon of the digastric passes between the major and minor stylohyoidei. 



id) The geniohyoideus. Unpaired. Origin: Mandibular sym- 

 physis. Insertion : Ventral surface of the body of the hyoid. 



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

 immediately behind the symphysis. The fibres pass upward 

 and slightly backward into the substance of the tongue. 



(/) 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. It contains fibres 

 for general sensibility and near its point of origin is joined by the chorda 

 tympani (p. 322), the latter containing gustatory fibres. 



{i) The twelfth cranial or hypoglossal nerve (n. hypoglossus) 

 enters the base of the tongue. It lies on the lateral side of 

 the external carotid artery and on the medial side of the 

 stylohyoideus major. It is distributed as a motor nerve to 

 the lingual muscles. 



(j) The ramus lingualis of the ninth cranial, or glossopharyn- 

 geal nerve (n. glossopharyngeus), enters the base of the 

 tongue at a point dorsal to the hypoglossus and between 

 the stylohyoideus minor and the stylopharyngeus. It is a 

 gustatory nerve of the tongue. 



8. Dissection of the extra-cranial roots of the ninth to twelfth 



nerves (Fig. 109). 



These nerves, which for the most part have already been exposed, 

 may be traced to their origin in the jugular and hypoglossal fora- 



