SPHENO-PALATINE GANGLION. 139 



found), the hinder part of the loose piece of mucous membrane before de- 

 tached from the septum nasi, and separate the mucous membrane from 

 the outer wall of the nasal fossa, behind the spongy bones, as high as the 

 spheno-palatine foramen. In reflecting forwards the membrane many 

 branches of vessels and nerves will be seen entering it through the fora- 

 men ; but these may be left for the present, as directions for their dissec- 

 tion will be subsequently given. When the lining membrane of the nose 

 has been removed behind the spongy bones, palatine nerves and vessels 

 will appear through the thin translucent palate bone, and will be readily 

 reached by breaking carefully through it with a chisel. Afterwards the 

 tube of membrane containing the palatine vessels and nerves being opened, 

 these are to be followed down to the soft palate and the roof of the mouth, 

 and upwards to the ganglion which is close to the body of the sphenoid 

 bone. 



To bring the ganglion fully into view, it will be necessary to saw through 

 the overhanging part of the sphenoid bone, to cut away pieces of the bones 

 surrounding the hollow in which it lies, and to remove with care the 

 enveloping fat and the periosteum. The ganglion then appears as a flat- 

 tened reddish-looking body, from which the vidian and pharyngeal nerves 

 pass backwards. Besides the branches referred to, the student should 

 seek two large nerves from the upper part of the ganglion to join the 

 upper maxillary, and smaller offsets to the floor of the orbit. 



To trace backwards the vidian branch to the carotid plexus and the 

 facial nerve, the student must lay open the canal which contains it and 

 its artery in the root of the pterygoid process; and in doing this he must 

 define the small pharyngeal branches of nerve and artery which are super- 

 ficial to the vidian, and lie in the pterygo-palatine canal. At the back of 

 the pterygoid canal, a small branch from the vidian to the plexus on the 

 internal carotid artery is to be looked for. Lastly, the vidian nerve is to 

 be followed, into the skull through the cartilage in the foramen lacerum 

 (basis cranii), after cutting away the point of the petrous portion of the 

 temporal bone, and dividing the internal carotid artery; and it is to be 

 pursued on the surface of the temporal bone, beneath the ganglion of the 

 fifth nerve, to the hiatus Fallopii : its junction with the facial nerve will 

 be seen with the dissection of that nerve. 



The branches of the ganglion to the nose will be found entering the 

 outer surface of the detached mucous membrane opposite the spheno-pala- 

 tine foramen, with corresponding arteries. One of these nerves (naso- 

 palatine), before dissected in the membrane of the septum, is to be isolated, 

 and to be followed forwards to where it enters the floor of the nose. The 

 branches of the internal maxillary artery with the nerves are to be cleaned 

 at the same time. 



The SPHENO-PALATINE GANGLION (fig. 34, T ) (ganglion of Meckel) 

 occupies the spheno-maxillary fossa, close to the spheno-palatine foramen, 

 and is connected with the branches of the superior maxillary nerve to the 

 palate. The ganglionic mass is somewhat triangular in form, and of a 

 reddish-gray color. It is situate for the most part, behind the branches 

 (spheno-palatine) of the superior maxillary nerve to the palate, so as to sur- 

 round only part of their fibres ; and it is prolonged posteriorly into the 

 vidian nerve. MeckePs ganglion resembles the other ganglia in connec- 

 tion with the fifth nerve in having sensory, motor, and sympathetic offsets 

 or roots connected with it. 



The Branches of the ganglion are distributed for the most part to the 



