542 THE CEANIAL NERVES. 



be prolong-ed into it. passes backwards through the Vidian canal, and after 

 emerging from this divides in the substance of the fibro-cartilage, which fills the 

 foramen lacerum medium, into two branches : one of these, the superficial 

 petrosal, joins the facial nerve, while the other, the carotid branch, communi- 

 cates with the sympathetic. WTiilst the Vidian nerve is in its canal, it gives 

 inwards some small nasal branches, which supply the membrane of the back part 

 of the roof of the nose and septum, as well as the membrane covering the 

 end of the Eustachian tube. 



The large shjicrjicial jirtrosal hrancli of the Vidian nerve, entering the cranium 

 on the outer side of the carotid artery and beneath the Gassenan ganglion, is di- 

 rected backwards m a groove on the petrous portion of the temporal bone to the 

 hiatus Fallopii, and is thus conducted to the aqueductus Fallopii, where it joins 

 the gangliform enlargement of the facial nerve. 



The carotid or sii»ijMn?uTtr jicrtivn of the Vidian neiwe, shorter than the other, 

 is of a reddish colour and softer texture : it is directed backwards, and on the 

 outer side of the carotid artery ends in the filaments of the sympathetic suiTound- 

 ing that vessel. 



In accordance with the view taken of the ganglia connected with the fifth 

 nerve (p. 53()). the superficial petrosal and carotid parts of the Vidian nerve may 

 be regarded as the motor and sympathetic roots respectively of the spheno-pala- 

 tine ganglion ; the spheno palatme bemg its sensory root. 



The phari/niiral nt-rve is inconsiderable in size, and, instead of emanating 

 directly from the ganglion, is frequently derived altogether from the Vidian. 

 This branch, when a separate nerve, springs from the back of the ganglion, enters 

 the pterygo-palatine canal with an artery, and is lost in the lining membrane of 

 the pharynx behind the Eustachian tube. 



Summary. — Tlie superior maxillary nerve, with Meckel's ganglion, 

 supplies the intcfiument above the zyo^omatic arch, and that of the lower 

 eyelid, the side of the nose, and the upper lip ; the upper teeth, the 

 lininp,' meml)raae of the nose ; the membrane of the upper part of the 

 pharynx, of tiie antrum of Highmore, and of the posterior ethmoidal 

 cells ; the Roft palate, tonsil, and uvula , and the glandular and mucous 

 structures of the roof of the mouth. 



lir.-INFF,RIOR MAXILLARY NERVE. 



The lower maxillary nerve, the third and largest division of the fifth 

 nerve, is made uj) of two ])ortions, unequal in size, the larger being 

 derived from the Gassenan ganglion, and the smaller being the slender 

 motor root of the fifth nerve. These two parts leave the skull by the 

 foramen ovale ni the sphenoid bone, and unite immediately after then- 

 exit, A few lines beneath the base of the skull, and under cover of 

 the external pterygoid mu.scle, the nerve separates into two primary 

 divisions, one of which is higher m position and smaller than the other. 



ThesrnaU,an/crior,OY upperpor(io)i, chicQymoior,termmateii m branches 

 to the temporal, masseter, buccinator, and pterygoid muscles. The 

 larger or lower \)onion, chiefly sensor j', divides into the auriculo-temporal, 

 lingual or gustatory, and inferior dental branches ; it likewise supplies 

 the mylo-hyoid muscle, and the anterior belly of the digastric. Thebranch 

 to the internal pterygoid muscle, with which also are connected those 

 proceeding from the otic ganglion to the tensors of the palate and 

 tympanum, is sometimes counted as a part of the larger division, but is 

 more correctly regarded as arising from the undivided trunk. 



Deep temporal, masseteric and pterygoid branches. — The deep 

 temporal hraiirhes, two in number, anterior and posterior, pass out- 

 wards above the external pterygoid muscle, close to the bone, and 

 run upwards, one near the ft-ont, and the other near the back of the 



