[Stowell. 4ub [May 21, 



mesal border of the mandibular nerve (Fig. Pter. ext.) : about 2 mm, from 

 its origin it separates into three rami, which may be traced 8-10 mm. and 

 then penetrate the pterygoid muscle, upon which muscle its terminal fila- 

 ments ramify. 



N. buccalis is a large nerve which separates from the mesal border of 

 the mandibular nerve (Fig. Buccalis) just ventrad of the defep temporal 

 The first 5 mm. of its course is involved in the dense rete of the carotid 

 artery ; its direction is toward the caudal angle of the maxilla ; it is ap- 

 posed to the buccal artery, and lies between the pterygoid and the tempo- 

 ral muscles. It gives filaments to the mucosa of the mouth (Fig.), a lew 

 filaments to the malar border of the masseter muscle, and at the angle of 

 the mouth it joins the plexus already named — Plexus labialis (PI. lab.). 



N. dentalis inferior together with N. lingualis form the principal rami 

 or continuation of the mandibular nerve. It becomes a distinct nerve 

 about 5 mm. peripherad of the foramen ovale. It lies ectad of the ptery- 

 goid muscle, and enters the foramen infradentale with the mandibular 

 artery. It lies along the dental canal ventrad of the artery, and gives fila- 

 ments to the teeth (Fig. m., p. m., canine, incis.) and to the cancellous 

 interior of the mandible ; a considerable fascicle continues peripherad 

 through the mental foramen (Fm. men.); the terminal filaments anasto- 

 mose with filaments of its platetrope. 



N. mentalis is the continuation of the dental nerve peripherad of the 

 mental foramen ; it divides into several fasciculi, which anastomose in 

 plexiform relations upon the ventral lip, the chin and the mucosa of the 

 mandible. (N. digastricus and N. mylohyoideus join this plexus.) 



N. mylo-hyoideus is given from the mandibular nerve about 10 mm. 

 centrad of the infra- dental foramen ; its course is apposed to the facial 

 artery ; it lies entad of the artery as it crosses the mandible. Ventrad of 

 the mandible it gives an anastomotic filament to the facial ; it continues 

 1-2 mm. mesad of the submental artery, and, following its arterioles, is 

 distributed to the mylo-hyoid muscle. 



N. digastricus is a branch of the mylohyoid, or it may be regarded as a 

 branch of the mandibular nerve peripherad of the point where the mylo- 

 hyoid nerve lies ventrad of the mandible. About 3-4 mm. peripherad of 

 this origin it divides into cephalic and caudal rami (Fig.). The cephalic 

 ramus is apposed to the submental artery, supplies the distal half of the 

 digastric muscle, and terminates in plexiform relations with the mental 

 nerve ; the caudal ramus follows the digastric artery caudad about 10 mm., 

 and supplies the digastric muscle as far as the angle of the mandible. 



N. lingualis has a common origin with the dental nerve ; 5 mm. periph- 

 erad of the foramen ovale it takes a distinct course mesad of the dental 

 nerve ; it lies ectad of the pterygoid muscle, apposed to a small arteriole 

 just entad of the carotid and the dental arteries ; 15 mm. peripherad of its 

 origin it takes three courses : 



(1) The cephalic ramus, N. pharyngeus (Phar.), is distributed to the 



