SPHENO-PALAT1NE GANGLION. 603 



SPHENO-PALATINE GANGLION". 



The splieno-palatine ganglion, frequently named Meckel's ganglion, is 

 deeply placed in the spheno-maxillary fossa, close to the spheno-palatine 

 foramen. It receives the two spheno-palatine branches, which descend 

 together from the superior maxillary nerve as it crosses the top of the fossa. 

 It is of a greyish colour, triangular in form, and convex on the outer 

 surface. The grey or ganglionic substance does not involve all the fibres 

 of the spheno-palatiue branches of the upper maxillary nerve, but is placed 

 at the back part, at the point of junction of the sympathetic or deep 

 branch of the Vidian, so that the spheuo-palatine nerves proceeding to the 

 nose snd palate pass to their destination without being incorporated with 

 the gangliouic mass. 



Branches proceed from the ganglion upwards to the orbit, downwards to 

 the palate, inwards to the nose, and backwards through the Vidian and 

 pterygo-palatine canals. 



ASCENDING BRANCHES. There are three or more very small twigs, 

 which reach the orbit by the spheno-maxillary fissure, and are distributed to 

 the periosteum. 



Bock describes a branch ascending from the ganglion to the sixth nerve; Tiede- 

 mann, one to the lower angle of the ophthalmic ganglion. The filaments described 

 by Hirzel as ascending to the optic nerve, most probably join the ciliary twigs which 

 surround that nerve. 



DESCENDING BRANCHES. These are three in number, the large, the 

 small, and the external palatine nerves, and are continued chiefly from 

 the spheno-palatine branches of the superior maxillary. They are distri- 

 buted to the tonsil, the hard and soft palate, the gums, and the mucous 

 membrane of the nose. 



a. The larger or anterior palatine nerve descends in the palato-maxillary canal, 

 and divides in the roof of the mouth into branches, which are received into grooves 

 in the hard palate, and extend forwards nearly to the incisor teeth. In the mouth it, 

 supplies the gums, the glandular structure and the mucous membrane of the hard 

 palate, and joins in front with the naso-palatine nerve. When entering its canal, 

 this palatine nerve gives a nasal branch which ramifies on the middle and lower 

 spongy bones ; and a little before leaving the canal, another branch is supplied to 

 the membrane covering the lower spongy bone : these are inferior nasal branches. 

 Opposite the lower spongy bone springs a small branch, which is continued to the 

 soft palate in a separate canal behind the trunk of the nerve. 



1). The smaller or posterior palatine branch, arising near the preceding nerve, 

 enters with a small artery the lesser palatine canal, and is conducted to the soft 

 palate, the tonsil, and the uvula. According to Meckel, it supplies the levator 

 palati muscle. 



c. The external palatine nerve, the smallest of the series, courses between the 

 upper maxilla and the external pterygoid muscle, and enters the external palatine 

 canal between the maxillary bone and the pterygoid process of the palate bone. At 

 its exit from the canal it gives inwards a branch to the uvula, and outwards another 

 to the tonsil and palate. Occasionally, this nerve is altogether wanting. 



INTERNAL BRANCHES. These consist of the naso-palatine, and the upper 

 and anterior nasal, which ramify iii the lining membrane of the nasal fossae 

 and adjoining sinuses. 



The upper nasal are very small branches, and enter the back part of the nasal 

 fossa by the spheno-palatine foramen. Some are prolonged to the upper and 

 posterior part of the septum, and the remainder ramify in the membrane covering 



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