THE TRIGEMINAL NERVE. 



1245 



membrane of the anterior two-thirds of the dorsum. Its fibres have their main 

 termination in the filiform and fungiform papillae. 



The lingual nerve communicates with the chorda tympani and the inferior 

 dental and in its anterior portion forms loops with the hypoglossal. 



3. The inferior dental nerve (o. alveolaris inferior) (Fig. 1063) is the larger 

 of the terminal branches of the mandibular. Lying posterior and external to the 

 lingual, to which it is connected by a small nerve strand, it passes downward and 

 forward under cover of the external pterygoid. Leaving the lower margin of that 

 muscle, it runs between the ramus of the mandible and the spheno-mandibular 

 ligament and enters the inferior dental canal, along which it courses in company 



FIG. 1063. 



Motor division of mandibular ne 



Deep temporal branch 



Sensory division of mandibular nerve 



Internal pterygoid nerve 

 Chorda tympani nerve 

 Middle meningeal artery 



Auriculo- 

 temporal nerve 



Superficial 

 temporal artery 



Mylo-hyoid nerve 

 Internal 



maxillary artery 



Connection between 



auriculo-temporal 



and facial nerves 



Facial nerve 



Inferior dental nerve 

 Part of mandible 



Parotid gland 



External 

 carotid artery 



Mylo-hyoid nerve 



Ext. pterygoid 

 muscle, cut, and 

 its nerve 



Masseteric branch 

 giving off a temporal 

 branch 



Cut edge ot 

 buccinator 



Int. pterygoid muscle 

 Lingual nerve 



Mylo-hyoid muscle. 

 cut to show 

 lingual nerve 



Submaxillary ganglion 

 Digastric muscle, 

 anterior belly 



Submaxillary gland 



Dissection showing mandibular nerve and its branches : mandible has been partially removed, exposing inferior 



dental nerve in its canal. 



with the inferior dental artery, and supplies filaments to the teeth, as far as the mental 

 foramen. Here the nerve breaks up into its terminal branches, one of which, the 

 incisor, continues within the mandible to the mid-line, while the other and larger, the 

 mental, emerges at the mental foramen. 



Branches. These are : () the mylo-hyoid, (b) the dental, (c} the incisor 

 and (</) the -mental, of which the last two are terminal branches. 



a. The mylo-hyoid nerve (n. mylohyoideus) (Fig. 1063) is the only motor strand in the 

 posterior division of the mandibular nerve. It arises from the inferior dental nerve, just 

 before the latter enters its bony canal, and passes downward and forward in the mylo-hyoid 

 groove, sometimes a canal for part of the way, in the mandible. The nerve descends into 

 the digastric triangle and reaches the inferior surface of the mylo-hyoid muscle, in this situation 

 being overlain by the Submaxillary gland and the facial artery and vein. It here breaks up into 

 filaments which supply the mylo-hyoid muscle and the anterior belly of the digastric. 



b. The dental branches (rr. dentales inferiores) are given off as the nerve traverses the 

 inferior dental canal. They combine and unite to form the inferior dental plexus (plexus 



