Trifacial Nerve 63 



MeckePs ganglion lies in the spheno-maxillary fossa, being con- 

 nected with the under part of the superior maxillary nerve by the twigs 

 which constitute its sensory root. Its motor filament comes from the 

 facial through the Vidian nerve, and this also brings a sympathetic 

 communication from the carotid plexus. Branches from the ganglion 

 supply the nasal fossa, gums, soft palate and uvula, roof of mouth, 

 upper part of pharynx, Eustachian tube, tonsil, levator palati, azygos 

 uvulae, and palato-glossus and pharyngeus. 



The infra-orbital nerve is found by dividing the orbicularis and the 

 levator labii superioris above the second bicuspid tooth. If it is desired 

 to remove the nerve, and also Meckel's ganglion, the course of the nerve 

 may be followed backwards by trephining the front of the antrum 

 and by breaking along the infra-orbital canal. The spheno-maxillary 

 fossa is thus reached, and the nerve is found emerging through the 

 foramen rotundum, near which it is to be cut with curved scissors. 



The inferior maxillary nerve leaves by the foramen ovale, and 

 divides into an anterior and a posterior trunk. Most of the motor 

 root of the fifth nerve enters the anterior trunk, from which the follow- 

 ing branches pass off: the masseteric, which, in its course through 

 the sigmoid notch, supplies the temporo-maxillary joint ; deep tem- 

 poral, and pterygoid. It also gives a large buccal branch which 

 traverses the external pterygoid : this is not, however, the motor nerve 

 to the buccinator, for when the facial nerve is damaged that muscle 

 is completely paralysed (p. 67). This buccal branch of the inferior 

 maxillary is a sensory nerve, and ends in the supply of the skin and 

 mucous membrane of the cheek. Thus, when the motor part of the 

 fifth nerve is impaired there is paralysis of all the muscles of mastica- 

 tion on that side, with exception of the buccinator, which is supplied 

 by the seventh. Rut, nevertheless, mastication does not appear to be 

 much affected, as it is being efficiently carried on by the muscles of 

 the opposite side. 



The posterior trunk of the inferior maxillary nerve gives off the 

 auriculo-temporal, gustatory, and inferior dental branches. The 

 auriculo-temporal embraces the middle meningeal artery between its 

 two heads of origin, it then turns up behind the condyle of the lower 

 jaw and beneath the parotid gland, giving off auricular and temporal 

 branches. The former supply the front part of the pinna and the 

 meatus, whilst the latter end in the skin of the temple. The auriculo- 

 temporal also gives twigs to the temporo-maxillary joint and the 

 parotid gland, and supplies the sensory root to the otic ganglion. 



The gustatory nerve descends between the two pteiygoids, across 

 the superior constrictor, along the side of the tongue and to its tip, 

 lying just beneath the mucous membrane. It is a nerve of extremely 

 delicate but common sensation. It is joined in the pterygoid region 

 by the chorda tympani (p. 66), and upon the hyo-glossus by branches 

 of the hypo-glossal ; it gives branches to the anterior two-thirds of the 



