THE NOISE. 



885 



THE NOSE. 



The nose is the special organ of the sense of smell : by means of the peculiar 

 properties of its nerves it protects the lungs from the inhalation of deleterious 

 gases and assists the organ of- taste in discriminating the properties of food. 



Seen from below. 



Side view. 



Lower lateral cartilage. 



Sesamoid cartilages. 



FIGS. 521, 522. Cartilages of the nose. 



The organ of smell consists of two parts one external, the nose ; the other 

 internal, the nasal fossce. 



The nose is the more anterior and prominent part of the organ of smell. It is 

 of a triangular form, directed vertically downward, and projects from the centre 

 of the face immediately above the upper lip. Its summit or root is connected 

 directly with the forehead. Its inferior part, the base of the nose, presents two 

 elliptical orifices, the nostrils, separated from each other by an antero-posterior 

 septum, the columna. The margins of these orifices are provided with a number 

 of stiff hairs, or vibrissce, which arrest the passage of foreign substances carried 

 with the current of air intended for respiration. The lateral surfaces of the nose 

 form, by their union, the dorsum, the direction of which varies considerably in 

 different individuals. The dorsum terminates below in a rounded eminence, the 

 lobe of the nose. 



The nose is composed of a framework of bones and cartilages, the latter being 

 slightly acted upon by certain muscles. It is covered externally by the integument, 

 internally by mucous membrane, and supplied with vessels and nerves. 



The bony framework occupies the upper part of the organ : it consists of the 

 nasal bones and the nasal processes of the superior maxillary. 



The cartilaginous frametvork consists of five pieces, the two upper and the two 

 lower lateral cartilages and the cartilage of the septum. 



The upper lateral cartilages are situated below the free margin of the nasal 

 bones ; each cartilage is flattened and triangular in shape. Its anterior margin is 

 thicker than the posterior, and connected with the fibro-cartilage of the septum. 

 Its posterior margin is attached to the nasal process of the superior maxillary and 

 nasal bones. Its inferior margin is connected by fibrous tissue with the lower 

 lateral cartilage : one surface is turned outward, the other inward toward the 

 nasal cavity. 



The lower lateral cartilages are two thin, flexible plates situated immediately 

 below the preceding, and bent upon themselves in such a manner as to form the 

 inner and outer walls of each orifice of the nostril. The portion which forms the 

 inner wall, thicker than the rest, is loosely connected with the same part of the 

 opposite cartilage, and forms a small part of the columna. Its inferior border, 

 free, rounded, and projecting, forms, with the thickened integument and subja- 



