NASAL FOSSAE AND SINUSES OF THE NOSE. 33 



There are also branches from the superior dental 

 (internal maxillary) to the antrum, from the infra-or- 

 bital, from the pterygo-palatine, and from the ethmoidal 

 (ophthalmic) and facial. 



Veins. The veins form a peculiarly complicated 

 plexus (rete nasi), which collect and pass forwards, 

 terminating in the facial vein; others pass into the 

 frontal vein, and another set pass through the spheno- 

 palatine foramen into the plexus in the zygomatic fossa. 



Nerves. There are two sets of nerves distributed to 

 the mucous membrane of the nose, viz. () those of 

 special sense ; (/?) those of common sensation. 



() The olfactory, derived from the olfactory lobe, 

 penetrates in three layers the cribriform plate of the 

 ethmoid bone, and is distributed to the ethmoidal and 

 sphenoidal spongy bones, and to the upper part of the 

 septum, (ft) Those derived from the fifth are the nasal 

 from the ophthalmic division, which passes to the an- 

 terior part of the mucous membrane, and leaves the 

 cavity of the nose by passing between the lateral car- 

 tilage and the nasal bone (entering by the nasal slit). 

 From MeckePs ganglion are given off the spheno-pal- 

 atine branch for the septum and the external parietes ; 

 the posterior and inferior nasal from the anterior pal- 

 atine, which is distributed to the posterior inferior por- 

 tion of the external wall. 



There is a point of considerable practical importance 

 with regard to the relation borne by the velum pen- 

 dulum palati to the posterior nasal apertures. If the 

 mouth be opened, there is an involuntary disposition to 

 breathe through it, and thus the palate applies itself 

 closely to the walls of the pharynx, cutting off the com- 

 munication between the nose and mouth. In syring- 



