68 THE NERVOUS SYSTEM 



lateral to the cavernous sinus, and passes through the fora- 

 men rotundum in the great wing of the sphenoid (Fig. 35). It 

 then runs obliquely across the uppermost part of the pterygo- 

 palatine (spheno-maxillary) fossa and enters the orbit through 

 the inferior orbital (spheno-maxillary) fissure (Fig. 38). 



In this part of its course the maxillary nerve can be reached 

 with a hypodermic needle for the purpose of injecting absolute 

 alcohol, or some other destructive agents, into and around it. 

 The needle is entered immediately below the zygomatic arch 

 at a point 4 cms. in front of the anterior wall of the external 

 acoustic meatus (Symington). The nerve lies at a depth of 

 5 cms. from the surface, but it is probable that, before it 

 reaches this depth, the needle will impinge either on the 

 posterior part of the maxilla or on the lateral pterygoid lamina 

 (Fig. 38). It will require to be withdrawn partially and 

 re-inserted until it passes through the pterygo-maxillary fissure 

 and enters the pterygo-palatine (spheno-maxillary) fossa. The 

 contents of the syringe can then be injected around the 

 maxillary nerve. 



As the maxillary nerve lies in the pterygo-palatine fossa, it 

 is connected to the spheno-palatine (Meckel's) ganglion by 

 two roots (Fig. 38). 



The Spheric-Palatine Ganglion receives additional 

 afferent fibres from the nervus canalis pterygoidei (Vidian 

 nerve), which is formed by the union of the greater superficial 

 petrosal nerve from the facial with the deep petrosal nerve 

 from the cervical sympathetic. Branches arise from the 

 ganglion and are distributed to the mucous membrane (i) 

 of the lateral walls and septum of the nose^ (2) of the hard 

 palate and gums, (3) of the soft palate and the palatine 

 (faucial) tonsil^ and (4) of the roof of the nasal part of the 

 pharynx. 



It is possible that the spheno-palatine ganglion takes part 

 in the innervation of the muscles of the soft palate, but this 

 view is not generally accepted (p. 96). 



In the orbit, the maxillary nerve gives off the zygomatic 



