730 



NOSE. 



the surface of the skin. Their secretion is 

 copious, so that after death a mass of seba- 

 ceous matter may be squeezed from the orifice 

 of each hair-follicle ; and their ducts as well 

 as the follicles themselves are said to be espe- 

 cially liable to be infested by the acurus Jol- 

 liculorum lately discovered by Dr. Simon.* I 

 find none of the simple utricular follicles de- 

 scribed by Cloquet and others in the skin of 

 the nose; probably they were empty hair fol- 

 licles. 



On the upper three-fourths of the nose, the 

 skin moves freely on the subjacent bones and 

 cartilages, a thin layer of pliant cellular and 

 adipose tissue being placed between them. In 

 the lower fourth, and especially about the base 

 of the nose, the skin is thicker and more com- 

 pact than it is above; there is very little fat 

 beneath it, and what there is is arranged in 

 small and discrete granules; and the cutis, 

 muscle, and fibrous membrane are so closely 

 connected that they are moved together as one 

 mass. 



At the nostrils the skin of the nose turns in- 

 wards and is continuous with the mucous 

 membrane, which, after lining the nasal fossae 

 and the cavities opening into them, is con- 

 tinued into the pharynx through the posterior 

 nares, and into the nasal duct and Eustachian 

 tube. The boundary between the skin and 

 mucous membrane cannot be strictly drawn. 

 It may be fixed, however, at the part just below 

 which those hairs are implanted which con- 

 verge from the inner circumference towards the 

 centre of the nostril, so as to entangle any light 

 body floating in the inspired air. These hairs 

 are of the kind named vibrissee. Like the eye- 

 lashes they are short, stiff, slightly curved, aud 

 pointed at their free extremities ; and they are 

 peculiarly well adapted for examining the mi- 

 nute structure of hair. In them also, as well 

 as in the eye-lashes, one may best see the mode 

 in which hairs are shed. In all which fall off 

 spontaneously, or which, being about to fall, 

 may be pulled away without pain, the conical 

 cavity at the lower end, into which the vascular 

 pulp fitted, is closed, having gradually con- 

 tracted and shifted itself off the pulp as the 

 hair ceased to be nourished and died. 



The follicles of these hairs are similar to 

 those of the hairs of the external integument, 

 and each of them is associated with sebaceous 

 glands, which, like those accompanying the 

 hairs about the orifice of the vagina, are more 

 numerous than in parts less exposed to the con- 

 tact of fluids. A whorl of four or more small 

 glands is often associated with a single hair- 

 follicle ; and when the hairs fall off, and their 

 follicles partially close, the glands open, as if 

 directly, by a common duct upon the surface. 



The mucous membrane (Schneiderian or pitu- 

 itary membrane) of the nose is far from uni- 

 form in its different parts. It is everywhere, 

 and in some parts inseparably, connected witli 

 the periosteum or perichondrium which imme- 

 diately covers the bones and cartilages, and 

 which is often spoken of as the internal or deep 



layer of the fibro-wucous membrane ; but, while 

 tiie latter is in all parts nearly similar, dirlering 

 only in thickness and degree of vascularity, 

 the mucous membrane itself presents con- 

 siderable diversities. 



In the antrum and other supplemental cavi- 

 ties of the nose the mucous membrane is thin, 

 but little vascular, and of the simplest kind, 

 having neither papillae nor glands embedded 

 in it. On the turbinated bones, the septum, 

 and the floor of the nostrils, it is thick, spongy, 

 red, and turgid with blood collected in the 

 plexus of large vessels in its areolar tissue. 

 These vessels seem to form in some parts a 

 distinct layer between the periosteum and the 

 proper mucous membrane, but they are ex- 

 actly analogous to those of the areolar or sub- 

 mucous tissue of other compound mucous 

 membranes, in all of which there is a plane of 

 large vessels from which those of smaller size 

 ascend to the apparatus disposed upon the 

 surface. In the Schneiderian membrane the 

 veins of this plexus far exceed the arteries in 

 size, and their close connection with the veins 

 within the skull may be a provision for re- 

 lieving the latter when subjected to an undue 

 pressure of blood. The epistaxis of plethoric 

 persons and of those who read hard probably 

 has its origin in this connection ; for the pres- 

 sure of the blood in the congested cerebral 

 vessels being communicated to the walls of 

 these of the mucous membrane, these will 

 burst more readily than those which are on 

 every side supported by scarcely yielding tis- 

 sues. The size of these veins, too, and the 

 facility with which they permit distension, 

 (almost resembling in this the veins of an 

 erectile tissue,) account for the rapidity with 

 which the membrane sometimes swells up, so 

 as in a minute or two to obstruct the passage 

 of the nose. 



The free surface of that portion of the mu- 

 cous membrane which lines the proper cavities 

 of the nose is smooth. It presents the orifices 

 of many simple follicles or crypts. They are 

 most numerous about the lower and anterior 

 parts of the walls of the fossae, are of various 

 sizes, and in many places lie in groups or rows. 

 The follicles themselves are hemispherical, or 

 deep and more or less elongated. At the lower 

 and anterior part of the septum, there is often 

 a single long duct running horizontally and 

 leading to a collection of gland-cells which all 

 appear to open into it ; and, generally, some 

 others of the larger orifices are connected with 

 composite glands. 



The epithelium of the nose is, in part, of the 

 laminated, in part of the ciliary, kind. Ilenle* 

 says that if an imaginary plane section of the 

 nose be made from the anterior free border of 

 the nasal bones to the anterior nasal spine of 

 the superior maxillary bones, all the mucous 

 membrane below and in front of this plane is 

 covered by laminated epithelium, and all above 

 and behind it by ciliary epithelium. The latter 

 covers not only all the walls of the nasal fossa;, 

 but is continued from them to the surface of 



Mullcr's Archiv. 1842, p. 218. 



Allgcmcinc Anatomic, p. 246. 



