680 



ORGANS OF SENSE. 



Fig. 367. Nerves of Septum of Nose. 

 Side. 



Eight 



a single or double valvular mucous fold, and the anterior palatine canal either 

 completely closed in, or a tubular cul-de-sac of mucous membrane is continued 

 a short distance into it. 



In the roof, the opening leading to the sphenoidal sinus is narrowed, and the 

 apertures in the cribriform plate'of the ethmoid completely closed in. 



The arteries of the nasal fossse are the anterior and posterior ethmoidal, from 

 the ophthalmic, which supply the ethmoidal cells, frontal sinuses, and roof of 

 the nose ; the spheno-palatine, from the internal maxillary, which supplies the 

 mucous membrane covering the spongy bones, the meatuses, and septum ; and 

 the alveolar branch of the internal maxillary, which supplies the lining mem- 

 brane of the antrum. The ramifications of these vessels form a close, plexiform 

 network, beneath and in the substance of the mucous membrane. 



The veins of the nasal fossse form a close network beneath the mucous mem- 

 brane. They pass, some with the veins accompanying the spheno-palatine 



artery, through the spheno-palatine 

 foramen; and others, through the al- 

 veolar branch, join the facial vein ; 

 some accompany the ethmoidal arte- 

 ries, and terminate in the ophthalmic 

 vein ; and, lastly, a few communicate 

 with the veins in the interior of the 

 skull, through the foramina in the 

 cribriform plate of the ethmoid bone, 

 and the foramen caecum. 



The nerves are, the olfactory, the 

 nasal branch of the ophthalmic, fila- 

 ments from the anterior dental branch 

 of the superior maxillary, the Vidian, 

 naso-palatine, descending anterior pala- 

 tine, and spheno-palatine branches of 

 Meckel's ganglion. 



The olfactory, the special nerve of tho 

 sense of smell, is distributed over tho 

 upper third of the septum, and over the surface of the superior and middle 

 spongy bones. 



The nasal branch of the ophthalmic distributes filaments to the upper and 

 anterior part of the septum, and outer wall of the nasal fossae. 



Filaments from the anterior dental branch of the superior maxillary supply the 

 inferior meatus and inferior turbinated bone. 



The Vidian nerve supplies the upper and back part of the septum, and supe- 

 rior spongy bone; and the upper anterior nasal branches from the spheno- 

 palatine ganglion, have a similar distribution. 



The naso-palatine nerve supplies the middle of the septum. 

 The larger, or anterior palatine nerve, supplies the middle and lower spongy 

 bones. 



THE EYE. 



The Eyeball is contained in the cavity of the orbit. In this situation it is 

 securely protected from injury, whilst its position is such as to insure the most 

 extensive range of sight. It is acted upon by numerous muscles, by which it 

 is capable of being directed to any part, supplied by vessels and nerves, and is 

 additionally protected in front by several appendages, such as the eyebrow, 

 eyelids, &c. 



The eyeball is spherical in form, having the segments of a smaller and mere 

 prominent sphere engrafted upon its anterior part. It is from this circumstance 

 that the antero-posterior diameter of the eyeball, which measures about an inch, 

 exceeds the transverse diameter by about a line. The segment of the larger 



