612 



ORGANS OF THE SENSES. 



Fig. 301.- 



-Bones and Cartilages of Septum of Nose. 

 Right Side. 



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 lony framework occupies the upper part of the organ ; it consists of the 

 nasal bones, and the nasal processes of the superior maxillary. 



The cartilaginous framework 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 outwards, the other inwards towards the 

 nasal cavity. 



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



below the preceding, and curved 

 in such a manner as to form the 

 inner and outer walls of each 

 orifice of the nostril. The por- 

 tion 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 

 outer extremity, free, rounded, 

 and projecting, forms, with the 

 thickened integument and sub- 

 jacent tissue, the lobe of the 

 nose. The part which forms the 

 outer wall is curved to correspond 

 with the ala of the nose; it is 

 oval and flattened, narrow behind, 

 where it is connected with the 

 nasal process of the superior 

 maxilla by a tough fibrous 

 membrane, in which are found 



three or four small cartilaginous plates, cartilagines minores or sesamoid cartilages. 

 Above, it is connected to the upper lateral cartilage and front part of the cartilage 

 of the septum ; below, it is separated from, the margin of the nostril by dense 

 cellular tissue ; and in front, it forms, with its fellow, the prominence of the tip of 

 the nose. 



The cartilage of the septum is somewhat triangular in form, thicker at its mar- 

 gins than at its centre, and completes the separation between the nasal fossse in 

 front. Its anterior margin, thickest above, is connected from above downwards 

 with the nasal bones, the front part of the two upper lateral cartilages, and the 

 inner portion of the two lower lateral cartilages. Its posterior margin is con- 

 nected with the perpendicular lamella of the ethmoid ; its inferior margin witl} 

 the vomer and palate processes of the superior maxillary bones. 



These various cartilages are connected to each other, and to the bones, by a 

 tough fibrous membrane, the perichondrium, which allows the utmost facility of 

 movement between them. 



The muscles of the nose are situated immediately beneath the integument ; they* 

 ure (on each side) the Pyramidalis nasi, the Levator labii superioris alseque nasi, 

 the Dilator naris anterior, and Dilator naris posterior, the Compressor naris, the 

 Compressor narium minor, and the Depressor ala? nasi (see p. 246). 



The integument covering the dorsum and sides of the nose is thin, and loosely 

 connected with the subjacent parts; but where it forms the tip or lobe and the 



