396 NEUROLOGY, OR ANATOMY OF NERVOUS SYSTEM 



circular canals; the latter sends branches to the saccule, to 

 the ampulla of the posterior canal, and to the cochlea. 



The cochlear branch sends its filaments through the canals 

 of the modiolus, and these form the ganglion spirale. This 

 ganglion sends other filaments to the sulcus spirale and organ 

 of Corti. 



THE NOSE 



The nose is the organ of smell, and consists of an external 

 part, the nose, and an internal, the nasal fossae. 



The nose is pyramidal, and is formed by the nasal bones 

 and nasal processes of the superior maxillary bones, and of 

 five cartilages, viz., the two upper and the two lower lateral 

 cartilages, and the cartilage of the septum. The two open- 

 ings, the anterior nares, are directed downward, and just 

 inside of them are some short, stiff hairs, the vibrissse. The 

 bones and cartilages are covered by skin on the outer side 

 and by mucous membrane on the inner. Between the anterior 

 nares is a fold of skin, the columna nasi, which continues the 

 septum. The two lateral parts join in front to form the dorsum 

 and this ends below in the rounded lobe of the nose. 



The upper lateral cartilages lie one on each side, below the 

 nasal bones, and are triangular in form. The anterior margin 

 joins its fellow above and the edge of the cartilage of the sep- 

 tum below. The inferior edge joins the lower lateral cartilage 

 by means of fibrous tissue, and the posterior edge the nasal 

 and superior maxillary bones. 



The lower lateral cartilages are thin, and are curved so as 

 to form the front and both walls of the nostrils. Behind it is 

 attached to the superior maxilla, above to the upper cartilage. 

 Between it and the former several smaller cartilages may be 

 seen. It also joins a small part of the cartilage of the septum. 

 In front it joins its fellow to form the tip of the nose. 



The cartilage of the septum is quadrilateral, and thinner at 

 the centre than at its borders. It forms the anterior part of 

 the septum, and is joined superiorly to the nasal bones, and 

 to the upper and lower lateral cartilages by its anterior margin. 

 Its posterior margin is attached to the front of the perpendicular 

 plate of the ethmoid, and its lower margin to a groove on the 

 vomer and the ridge between the superior maxillae. 



