STRUCTURE OF THE NOSE. 443 



with the forehead by means of a narrow bridge ; inferiorly, it presents two 

 openings, the nostrils , which overhang the mouth, and are so constructed 

 that the odour of all substances must be received by the nose before they 

 can be introduced within the lips. The septum between the openings of 

 the nostrils is called the columna. Their entrance is guarded by a num- 

 ber of stiff hairs (vibrissce) which project across the openings, and act as a 

 filter in preventing the introduction of foreign substances, such as dust or 

 insects, with the current of air intended for respiration. 



The anatomical elements of which the nose is composed, are 1. In- 

 tegument. 2. Muscles. 3. Bones. 4. Fibro-cartilages. 5. Mucous 

 membrane. 6. Vessels and nerves. 



1. The Integument forming the tip (lobulus) and wings (alee) of the nose 

 is extremely thick and dense, so as to be with difficulty separated from 

 the fibro-cartilage. It is furnished with an abundance of sebiparous folli- 

 cles, which, by their oily secretion, protect the extremity of the nose in 

 excessive alternations of temperature. The sebaceous matter of these fol- 

 licles becomes of a dark colour upon the surface, from the attraction of the 

 carbonaceous matter floating in the atmosphere ; hence the spotted ap- 

 pearance which the tip of the nose presents in large cities. When the 

 integument is firmly compressed, the inspissated sebaceous secretion is 

 squeezed out from the follicles, and taking the cylindrical form of their 

 excretory ducts, has the appearance of small white maggots with black 

 heads. 



2. The Muscles are brought into view by reflecting the integument : 

 they are the pyramidalis nasi, compressor nasi, dilatator naris, levator labii 

 superioris alasque nasi, and depressor labii superioris alseque nasi. They 

 have been already described with the muscles of the face. 



3. The Bones of the nose are, the nasal, and nasal processes of the su- 

 perior maxillary. 



4. The Fibro-cartilages give form and stability to 



the outwork of the nose, providing, at the same time, Fig. 198* 



by their elasticity, against injuries. They are five in 

 number, namely, the 



Fibro-cartilage of the septum, 

 Two lateral fibro-cartilages, 

 Two alar fibro-cartilages. 



The Fibro-cartilage of the septum, somewhat trian- 

 gular in form, divides the nose into its two nostrils. 

 It is connected above with the nasal bones and lateral 

 fibro-cartilages ; behind, with the ethmoidal septum 

 and vomer ; and below, with the palate processes of 

 the superior maxillary bones. The alar fibro-carti- 

 lages and columna move freely upon the fibro-cartilage 

 of the septum, being but loosely connected with it by 

 perichondrium. 



The Lateral fibro-cartilages are also triangular: they are connected, in 

 front, with the fibro-cartilage of the septum ; above, with the nasal bones ; 



* The fibro-cartilages of the nose. 1. One of the nasal bones. 2. The fibro-cartilage 

 septum. 3. The lateral fibro-cartilage. 4. The alar fibro-cartilage. 5. The 

 il portions of the alar fibro-cartilages which constitute the col R mna. 6. The ap- 

 pendix of the alar fibro-cartilage. .7. The nostril. 



35 



