800 



THE ORGANS OF SENSE. 



In white races this index is below 70 (leptorhines) ; in yellow races, between 70 and 

 mesorhines) ; and in black races, above 85 (platyrhines). 



CARTILAGINES NASI. 



Five chief cartilages are concerned in the formation of the nose ; they are th 

 lateral and greater alar cartilages, on each side, and the cartilage of the septum. 



Cartilage Nasi Later alls. The lateral cartilage (Figs. 669, 670) is triangular i] 

 shape and is situated immediately below the nasal bone. Its posterior edge is thii 

 and is attached to the maxilla and the nasal bone ; its anterior edge is thick, am 

 its superior part is directly continuous with the cartilage of the septum ; its inferio 

 margin is joined, by fibrous tissue, to the upper edge of the greater alar cartilage. 



Cartilago Alaris Major. The greater alar cartilage (Figs. 668, 669, 670 

 encircles the anterior part of the nostril and assists in keeping it open. It consist 



Frontal air-sinus 



Nasal bon 



Perpendicular lamina of 

 ethmoid 



Cartilage of septum 



Medial crus 

 of left greater 

 alar cartilage 



Palatine bone 



FIG. 668. VIEW OF NASAL SEPTUM FROM THE LEFT SIDE. 



of a lateral and a medial crus, which are continuous with each other in a rounde< 

 angle at the apex of the nose. The lateral crus is oval in shape and is attache< 

 to the lateral cartilage and the maxilla by fibrous tissue. Above and behind it an 

 two or three lesser alar cartilages, while sometimes a horizontal furrow cuts off > 

 narrow linear part from its superior margin. The inferior edge of the lateral cru 

 does not descend as far as the opening of the nostril, the ala being there devoid o 

 cartilage and composed of fatty and connective tissue covered with skin. The media 

 crus (Fig. 668) bounds the medial wall of the nostril and lies in the septum mobile 

 below the anterior part of the cartilage of the septum. The medial crura of tb 

 two cartilages are separated, in front, by a notch which corresponds with the ape: 

 of the nose, and the posterior end of each curves slightly lateralwards and ends ii 

 a rounded extremity. 



Cartilago Septi Nasi. The cartilage of the septum (Fig. 668) is of ai 

 irregularly quadrilateral form. Its postero-superior edge is attached to the perpendi 

 cular lamina of the ethmoid; its postero-inferior margin to the vomer and the maxillae 

 Its antero-superior border is thick, and is fixed above to the back of the internasa 



