890 



ORGANS OF SPECIAL SEXSE 



projecting anterior nasal spine below. To this is added a yielding cartilaginous 

 portion, which completes the organ, and forms its chief part. 



The nose is enveloped in skin, lined by a mucous membrane, and supi^lied Avitli 

 vessels and nerves, and its cartilages are acted upon by small nmscles. 



The cartilages. — The principal cartilages are five in number : a i)air above, the 

 superior lateral; a pair below, the inferior lateral; and the cartilage of the 

 septum, the persistent unossified remnant of the facial segment of the chondro- 

 cranium (page 90). With these must be included a group of small irregular 

 cartilages known as sesamoid and accessory quadrate. 



The cartilages, ensheathed in perichondrium, are for the most part loosely 

 held together by tough intervening fibrous tissue, and this in turn becomes con- 

 tinuous with the periosteum of the surrounding bones. 



The upper lateral cartilages are nearly flat and somewhat triangular in shape, 

 each presenting an outer and an inner surface. 



Their anterior margins are continuous above with the rounded borders of a 

 shallow groove which furrows the cartilage of the septum; but below for about two- 

 thirds of their extent, though their edges are closely applied to the borders of the 



Fig. 513. — Antekiok View of the Nose, showing its Cartilages, etc. 



ORIFICE OF LACHRYMAL CANAL 



GROOVE ON ANTERIOR BORDER OF 

 SEPTAL CARTILAGE 



ACCESSORY QUADRATE CARTILAGES 1_ ^^ — -Z-"^ 



SESAMOID CARTILAGES 



CELLULAR TISSUE OF ALA 



«L NASAL PROCESS OF THE MAXILLA 



UPPER LATERAL CARTILAGE 



OUTER PLATE OF LOWER LATERAL 

 CARTILAGE 



groove, there is on each side a narrow cleft of separation Avhich opens out below 

 into an angular notch. 



Their curved posterior margins are firmly attached superficially by somewhat 

 jagged edges to the nasal bones; but deeply, and especially near the septum, they 

 underlie these bones for a considerable distance. 



The rest of the border is smooth, free, and loosely connected by intervening 

 fibrous tissue to the nasal process of the maxilla. 



Their inferior borders are connected with the lower lateral cartilages; one or 

 more narrow plates of cartilage occasionally intervene and fill the fibrous interval. 

 On account of their continuity Avith the septal cartilage, the upper lateral cartilages 

 should be regarded as its wings or lateral expansions. (Henle. ) 



The lower lateral cartilages are thin, pliant, and curved, and so folded back- 

 wards that each forms an inner and an outer plate. 



The inner plates are loosely attached to one another, where they meet below 

 the sejitum to form the tip of the nose and fore part of the columna. 



The outer plates are oval, and curve backwards above the masses of dense 

 cellular tissue which form the alee. They maintain the contour of the nostrils, 

 and serve to keep these orifices open. Posteriorly they are connected by fibrous 

 tissue to the nasal margins of the superior maxillary Itones. 



