THE XOSE 



891 



In this tissue are embedded several extremely tliin and irregular cartilages 

 named sesamoid, and above these commonly a pair still smaller, called accessory 

 quadrate. 



The septal cartilage fills in the triangular interval of the bony septum. The 

 anterior border is attached to the nasal bones at their junction below the crest. 

 Beyond it presents a shallow groove, the borders of M-hich are at first continuous 

 with the upper lateral cartilages, as already described. This groove becomes 

 narrowed by the gradual approximation of its borders, which ultimately meet in a 

 faint transverse ridge below. Still lower, it dips for a short distance between the 

 inner plates of the lower lateral cartilages, Avhich meet bej'ond it to form the tip 

 of the nose. 



The posterior border is connected with the perpendicular plate of the ethmoid, 

 wdiilst its inferior is attached to the vomer, which is often channelled like the 

 ethmoid plate to receive it. The anterior part of the lower border is attached to 

 the anterior nasal spine. 



The cartilage does not simply dip into the groove which is more or less marked 

 on the upper surface of the nasal spine, Vjut broadens out to obtain the widest 

 possible, though somewhat lax, attachment to it. Viewed from below, it appears 

 to embrace the spine. The border of its rounded angle in front is somewhat 



Fig. .514. — Uxder Vikw of the Xose, showixg its Cartilages, etc. 



septal cartilage 



OUTER PLATE OF LOWER LATERAL 

 CARTILAGE 



INNER PLATE OF LOWER LATERAL 

 CARTIUGE 



NASAL SPINE OF THE MAX'LLA 



SEPTAL CARTILAGE 

 Cellular tissue of ala 



thickened before terminating in a thin smooth edge. It is extremely thin near the 

 centre. 



The shape of the sejital cartilage varies in relation to the extent of ossification 

 in the bony septum, and even in the adult a strip of cartilage may extend for a 

 varying distance backwards and upwards between the vomer and ethmoid, some- 

 times even reaching the body of the sphenoid bone. 



It may be here noted that the septum of the nose is almost always straight in 

 children and in aboriginal skulls (eighty per cent.); but in Europeans it is deflected 

 to one or other side in the proportion of three out of every four. 



Jacobsonian cartilages. — In the septal cartilage above the opening of Stenson's 

 canal there is a small pouch which presents a minute opening below. This is the 

 representative of the so-called .lacobsonian organ. A strip of cartilage underneath 

 this, firmly adherent, but distinct from the septal cartilage, is known as the Jacob- 

 sonian cartilage. 



Muscles. — The muscles are seven in number, and may be grou]ied as dilators 

 and constrictors. The latter are comparatively feeble in their action. 



The dilators. — The pyramidaUs nasi is a downward prolongation of the 

 oceipito-frontalis. Each muscle descends on the side of the nose, to blend, after 

 becoming tendinous, with the compressor nasi. They diverge from one another as 

 they pass downAvards. The levator labii superioris alaeque nasi arises from the 

 nasal process of the maxilla. 



