408 



PHYSIOLOGY 



CHAP. 



the posterior border of the masseter the facial trunk divides into 

 many branches, which are distributed to all the muscles of the 

 face, to the buccinator and the platysma inyoides (Fig. 216). 



After some incomplete experiments by Bellingeri, Charles Bell 

 (1821) demonstrated that the facial is an exclusively motor nerve. 



Fin. 216. Superficial distribution of facial, trigeminal, and other nerves of head. (Sappey, after 

 Hirschfeld and LevcilK-.) f. Facial nerve I, trunk of facial nerve after its exit from stylo- 

 mastoid foramen ; 2, posterior auricular branch; 3, filament of great auricular nerve uniting 

 with foregoing ; 4, occipital branch ; 5, auricular branch ; 6, twig to superior auricular muscle ; 

 7, nerve to digastric, 8, that to stylo-hyoid muscle ; 9, superior or temporo-facial division of the 

 nerve; 10, 11, temporal branches ; 12, malar; 13, 14, buccal; 15, inferior or cervico-facial 

 division of the nerve ; 16, mandibular ; 17, cervical branch. Fifth nerve IS, auriculo-temporal 

 uniting with facial, giving anterior auricular and parotid branches, and ascending to temporal 

 region; 19, 20, supra-orbital; 21, lachrymal; 22, infra-trochlear ; 23, facial twig of zygomatic ; 

 24, superficial branch of naso-ciliary ; 25, infra-orbital ; 26, buccal, uniting with branches of 

 facial ; 27, mental. Cervical nerves 28, great occipital ; 29, great auricular ; 30, 31, small 

 occipital ; 32, superficial cervical. 



He proved that after section of this nerve the sensibility of the 

 face was unaffected, while the facial muscles were paralysed. After 

 him, many other physiologists confirmed, completed, and corrected 

 his observations, either by experimental section or by electrical and 

 mechanical excitation of the trunk of the facial and its branches. 



