548 



NERVOUS SYSTEM. 



in the cranium the two roots are distinct ; but after the small root passes 

 through the foramen, it is united by a mutual interlacement of fibres with 

 the sensory branch. 



The inferior maxillary nerve, made up of the motor root and the inferior 

 maxillary branch of the sensory root, just after it passes out by the foramen 

 ovale, divides into two branches, anterior and posterior. The anterior branch, 



which is the smaller, 

 is composed almost 

 entirely of motor 

 filaments and is dis- 

 tributed to the mus- 

 cles of mastication. 

 It gives off five 

 branches. The first 

 of these passes to 

 be distributed to 

 the masseter mus- 

 cle, in its course oc- 

 casionally giving off 

 a small branch to 

 the temporal mus- 

 cle and a filament 

 to the articulation 

 of the inferior max- 

 illa with the tem- 

 poral bone. The 

 two deep temporal 

 branches are dis- 

 tributed to the tem- 

 poral muscle. The 

 buccal branch sends 

 filaments to the 

 external pterygoid 

 and the temporal 

 muscles, and a small 

 branch is distribu- 



FIG. 197. Distribution of the small root of the fifth nerve (Hirschfeld). 

 1, branch to the masseter muscle ; 2, filament of this branch to the temporal 

 muscle ; 3, buccal branch' 4, branches anastomosing with the facial 

 nerve ; 5, filament from the buccal branch to the temporal muscle ; 6, 

 branches to the external pterygoid muscle ; 7, middle deep temporal 

 branch ; 8. auriculo-temporal nerve ; 9, temporal branches ; 10, auricu- 

 lar branches ; 11, anastomosis with the facial nerve ; 12, lingual branch ; 

 13, branch of the small root to the mylo-hyoid muscle ; 14, inferior den- 

 tal nerve, with its branches (15, 15) ; 16, mental branch ; 17, anastomosis 

 of this branch with the facial nerve. 



ted to the internal 



pterygoid muscle. From the posterior branch, which is chiefly sensory but 

 contains some motor filaments, branches are sent to the mylo-hyoid muscle 

 and to the anterior belly of the digastric. In addition the motor branch of 

 the fifth sends filaments to the tensor muscles of the velum palati. 



The above description gives in general terms the distribution of the 

 nerve of mastication, without taking into consideration its various anastomo- 

 ses, the most important of which are with the facial. Experiments have 

 shown that the buccinator muscle receives no motor filaments from the fifth 

 but is supplied entirely by the facial. The buccal branch of the fifth sends 



