282 SPECIAL ANATOMY. 



cess projects from it into the angle between lamina perpendicularis oss- 

 elhmoid. and Vomer. It separates the two halves of the nasal cavity. 



2. The muscles of the nose : levator labii alceq. nasi, compressor and dilata, 

 tores narium, depressor ales nasi, pyramidalis and depressor septi mobilis (see 

 Myology). 



3. The skin of the nose is very thick and strong on the alee nasi and below 

 the septum, and passes at the nares into the mucous membrane, the com- 

 mencement of which is beset with stiff hairs (vibrissce). It is also furnished 

 with many folliculi sebacei, which frequently appear as black punctules. 



4. Vessels and nerves. Arteries: branches of maxillaris externa , infra- 

 orbitalis, and ophthalmica. Veins form plexus nasalis. Nerves: branches of 

 plex. infraorbitalis and of N. ethmoidalis. 



519. B. The Cavity of the Nose, Nasus internus. 



The cavities of the nose,fossce nasales, are covered with the nasal 

 mucous membrane, membrana pituitaria s. Schneider iana, the 

 proper seat of the sense of smell. This membrane is thick, soft, 

 rosy red, very vascular and largely supplied with nerves (in the 

 neighbouring cavities, sinus frontales, ethmoidal., sphenoidal., and 

 antrum Highmori, we find .instead of it a delicate, fine periosteum 

 covered with ciliated epithelium.) Numerous mucous follicles cover 

 the free surface, whilst the external is firmly attached to the peri- 

 osteum and perichondrium. It continues upon the palate and pha- 

 rynx, the lacrymal canal, and Eustachian tube, the openings of 

 which, as well as those of the sinus, it generally covers like a veil. 

 [There is ciliated epithelium on the mucous membrane lining the 

 nose.] 



We observe in it the meatus narium: 



1. The superior nasal chamber, below the superior turbinate bones, with 

 the openings of the posterior ethmoid al and the sphenoidal cells. 



2. The central nasal chamber, below the middle turbinate bones, with 

 the openings of the anterior ethmoidal cells, the sinus frontalis, and 

 antra Highmori. 



3. The inferior nasal chamber, below the inferior turbinate bones, with 

 the openings of the canal, lacrymal. 



Vessels and Nerves: Art. sphenopalatina and ethmoidalis. Veins: form 

 very large plexuses, and pass into plex. pterygoid. and ven. maxillar. interna. 

 Lymphatics : form a very close superficial rete. 



Nerves : Nn. olfactorii, ethmoidales, naso-palatini Scarpcs, and nasales. 

 (Branches of Nerv. trigeminus). 



