892 



ORGANS OF SPECIAL SENSE 



It divides in its passage downwards, one slip being inserted into tlie eartilage of 

 the wing, the other extending to the ui)per lij) to l)lend with its nmscidar fibres. 



The tAvo foregoing niuseles may be regarded as extraordinary- or reserve muscles 

 of dilatation. 



The dilator naris consists of two small muscular slips, requiring a lens for 

 their proper demonstration; in some cases they are absent. 



The dilator naris anterior is a small and indistinct muscle. It is placed 

 between the skin and cartilage of the ala. 



The dilator naris posterior arises from the edge of the nasal notch of the 

 maxilla and the sesamoid cartilages, to be inserted into the margin of the nostril. 

 In paralysis of the facial nerve, a deep insjdration through the nostril j^roduces 

 complete collapse of its cartilaginous wall, thus showing tlie importance of the 

 dilator muscles in keeping patent the nasal orifices. 



The constrictors, or compressors. — The compressor naris arises from the 



Fig. 515. — Section showixg Boxy and Caetilagixous Septum. 

 The dotted lines indicate the coarse of the anterior palatine canal. 



Frontal sinus 



Sphenoidal sinus 



UPPER LATERAL CARTILAGE 



Groove between septal 

 and upper lateral 

 eartilage 



LOWER LATERAL 



THICKENED BUKUEH OF CARTILAGE RESTING I \ Pouch at upper 



UPON ANTERIOR NASAL SPINE Incisive papilla \ extremitv of St( 



ORIFICE OF EUSTACHIAN 

 Sten- TUBE 



SEPTAL CARTILAGE 8°°'^ °^°^1 SOFT PALATE 



maxilla near the incisive fossa, its fibres mixing with those of the levator anguli 

 oris. It expands as it passes inwards, to end in a thin aponeurosis, which joins 

 with its fellow as well as with the pyramidalis, and it also blends with the sul)- 

 cutancous tissue over the bridge of the nose. 



The depressor alae nasi arises from the incisor fossa; its fibres pass upwards 

 to the septum and ])osterior part of the Aving. 



The compressor narium minor consists of a few indistinct fibres, occasionally 

 found between the alar cartilage and skin over the tip of the nose. 



Tliese muscles are all supplied by the facial nerve. 



The skin covering the nose is for the most part thin and freely movable ujjon 

 the subjacent parts, Init at the tij) and over the cartilages it is much thicker and 

 more adherent and furnished with numerous sebaceous glands. 



The mucous membrane becomes continuous with the skin at the nasal orifices, 

 and ])osteriorly with the membrane which lines the nasal fossse. 



