388 SPECIAL ANATOMY. 



external to art. infraorbit.\ where it divides into fibres on the face, 

 and sends branches upwards : 



a. Rami palpebrales, to the skin, and under m. orbicularis, to 

 the conjunctiva of the inferior eyelid ; internally : 



b. Rami nasales, to the skin of the alee, nasi ; downwards : 



c. Rami labiales, to the upper lip, for the skin and mucous 

 membrane. These last are very numerous, and they anasto- 

 mose particularly with n.facialis. 



Before its entrance into the canal, infraorbitalis the trunk gives 

 off: 



1 . N. dentalis posterior superior ; it often arises with two to 

 three filaments (between which art. alveolaris poster.), de- 

 scends forwards upon the tuber maxillare, gives branches 

 to the m. buccinator [they most likely perforate this, and 

 supply the mucous membrane], the fat of the cheek, and 

 the gums. The superior branch penetrates, above tuber, 

 maxillare, the inferior below it, between the bony plates 

 of the upper jaw, into the canal, alveolar, poster., forms 

 there a plexus, from which one filament passes off for 

 each root of the molar teeth, and terminates in the dental 

 pulp. 



Inside the canalis infraorbitalis the trunk gives off: 



2. N. dentalis anterior superior, arising half an inch behind 

 for am. infraorbitale, is very large; it passes vertically 



down in a canal between the bony plates of the upper jaw 

 to a plane with the floor of the nose, and ramifies close to 

 that into : 



a. Ascending branches, which are lost in spina nasalis anter., 

 give a branch to the nasal mucous membrane and inferior 

 concha; and: 



b. Descending branches, for the first molar, the cuspidati, 

 and incisor teeth. 



637. Ramus III. n. trigemini s. N. maxillaris inferior. 



The inferior maxillary nerve is the largest and most posterior of 

 trigeminus, consisting of a posterior external fasciculus, which 

 comes from the gangl. Casseri, and an anterior internal fascicu- 

 lus, that is, the small root (motor fibres) of trigeminus. Course : 

 passes quickly out of the cranial cavity through foramen ovaleinto 

 the fossa zygomatica, where it immediately divides into eight 

 branches, of which the three first belong to the posterior, the five 

 others to the anterior fasciculus. 



