NASAL CAVITIES 307 



be done very carefully, in order to preserve intact the muco- 

 periosteum which clothes the opposite side of the septum. It 

 is in that muco-periosteum that the nerves and blood-vessels 

 must be examined. 



Vessels and Nerves of the Septum Nasi. The following 

 is a list of the nerves : 



Nerves of Smell, . Olfactory. 



!i. Naso-palatine. 

 2. Medial nasal branch of the anterior eth- 

 moidal nerve. 

 3. Nasa 1 branches from spheno- palatine 

 ganglion and from the nerve of the 

 _ pterygoid canal (O.T. Vidian). 



The Medial Group of Olfactory Nerves. The medial group 

 of olfactory nerves is associated with the muco-periosteum 

 of the upper part of the nasal septum and the various nerve 

 filaments are barely distinguishable, except in a fresh part ; 

 further, they are so soft that it is hardly possible to isolate 

 them. They proceed upwards in grooves on the surface of 

 the perpendicular lamina of the ethmoid, and leave the nasal 

 cavity through the medial series of apertures in the cribriform 

 plate of the same bone. 



Neruus Naso-palatinus. The naso-palatine nerve is a 

 long slender twig which can easily be detected upon the deep 

 surface of the muco-periosteum of the septum. It springs from 

 spheno-palatine ganglion, and enters the nasal cavity through 

 the spheno-palatine foramen. In the first part of its course 

 it runs medially, upon the inferior surface of the body of the 

 sphenoid. Having gained the nasal septum, it changes its 

 direction and passes downwards and forwards, in a shallow 

 groove on the surface of the vomer, under cover of the muco- 

 periosteum. Finally, it enters the foramen of Scarpa, and, 

 where the two foramina of Scarpa open into the common 

 incisive foramen, the nerves of opposite sides unite in a plexus 

 from which branches are given to the mucous membrane 

 covering the anterior part of the hard palate. The naso- 

 palatine nerve is accompanied by the posterior nasal septal 

 artery ; and, as it lies on the surface of the vomer, it supplies 

 some small twigs to the muco-periosteum of the septum nasi. 



A few nasal branches from the spheno-palatine ganglion, and 

 also from the nerve of the pterygoid canal, reach the muco- 

 periosteum over the superior and posterior part of the septum. 

 They are very minute, and it is questionable if the dissector 



