THE NOSE. 



819 



nasi. 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 (sesamoid cartilages cartllac/ines 

 minores). Above, it is connected by fibrous tissue to the upper lateral cartilage 

 and front part of the cartilage of the septum ; below, it falls short of the margin 

 of the nostril ; the ala being formed by dense cellular tissue covered by skin, 

 la front the lower lateral cartilages are separated by a notch which corresponds 

 with the point of the nose. 



The cartilage of the septum is somewhat quadrilateral in form, thicker at ils 

 margins than at its centre, and completes the separation between the nasal fossae 

 in front. Its anterior margin, thickest 



above, is connected with the nasal ^ \ 



bones, and is continuous with the ante- 

 rior margins of the two upper lateral 

 cartilages. Below, it is connected to 

 the inner portions of the lower lateral 

 cartilages by fibrous tissue. Its poste- 

 rior margin is connected with the per- 

 pendicular lamella of the ethmoid ; its 

 inferior margin with the vomer and the 

 palate processes of the superior maxil- 

 lary bones. 



It mav be prolonged backward (es- 

 pecially in children) for some distance 

 between the vomer and perpendicular 

 plate of the ethmoid, forming what is 

 termed the processes sphenoidalis. The 

 srptal cartilage does not reach as far as 

 the lowest part of the nasal septum. 

 This is formed by the inner portions of the lower lateral cartilages and by the 

 skin ; it is freely movable, and hence is termed the septum mobile nasi. 



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

 tough fibrous membrane, which allows the utmost facility of movement between 

 them. 



The muscles of the nose are situated beneath the integument : they are (on 

 each side) the Pyramidalis nasi, the Levator labii superioris alseque nasi, the 

 Dilatator naris, anterior and posterior, the Compressor nasi, the Compressor 

 narium minor, and the depressor alse nasi. They have been described above 

 (page 306). 



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 and the alse of the 

 nose it is thicker and more firmly adherent, and is furnished with a large number 

 of sebaceous follicles, the orifices of which are usually very distinct. 



The mucous membrane lining the interior of the nose is continuous with the 

 skin externally and with that which lines the nasal fossae within. 



The arteries of the nose are the lateralis nasi from the facial, and the inferior 

 artery of the septum from the superior coronary, which supply the alae and 

 septum, the sides and dorsum being supplied from the nasal branch of the 

 ophthalmic and the infra-orbital. 



The veins of the nose terminate in the facial and ophthalmic. 



The nerves for the muscles of the nose are derived from the facial, while the 

 skin receives its branches from the infra-orbital, infratrochlear, and nasal branches 

 of the ophthalmic. 



Fio. 436. Bones and cartilages of septum of nose. 

 Right side. 



