NOSE. 



733 



Fig. 404. 





Branches of the olfactory and naso-palatine nerres on 

 the septum of the nose. 



branches proceed which again form finer plex- 

 uses. They may be traced nearly to the lower 

 fourth of the septum. 



The external or labyrinthic branches are 

 rather more numerous and smaller. They 

 diverge and ramify like the preceding, lying in 

 the channels and grooves upon the upper two 

 turbinated bones. They have been traced to 

 the lower border of the middle turbinated bone, 

 but not to its outer concave surface, nor to any 

 part below it; yet the similarity of the structure 

 and arrangement of the inferior turbinated bone 

 and the mucous membrane over it makes it 

 very probable that they ramify on it also. The 

 middle branches are the longest; the posterior 

 ones form curves directed backwards towards 

 the sphenoidal sinuses, but not entering them. 

 At the posterior angle of the middle turbinated 

 bone some of them are described by Mr. Swan* 

 and by Soemmering as anastomosing with a 

 branch from the spheno-palatine ganglion ; but 

 Valentin -f could not find any such communica- 

 tion. A few branches in addition to these are 

 said to be distributed in the membrane covering 

 the cribriform plate itself (Cloquet). 



How the primitive filaments of the olfactory 

 nerve terminate has not yet been ascertained ; 

 their softness and the density of the tissue in 

 which they lie have hitherto prevented an accu- 

 rate observation of them in this part of their 

 course. 



Compared with the other nerves the olfactory 

 present many peculiarities of structure and 

 arrangement, especially in the part which is 

 within the skull. 1 . They are the softest of the 

 nerves within the skull, possessing only the 

 most delicate neurilema; and a rather less de- 

 gree of this softness is characteristic of their 

 branches, so thai their dissection is more diffi- 

 cult than that of any others of equal size. 2- 

 They have grey nervous matter both upon and 

 between their fasciculi, and their bulbs are not 



* Demonstrations of the Nerves, folio, p. 14, pi. 

 >:i. f. 3. 



f Loc. c. p. 303. 



like the ganglions of other nerves, but like 

 portions of the brain. 3. They are not, as 

 other nerves, cylindrical, but triangular in one 

 and flat in another part of their course. 4. 

 Their trunks converge, while those of all 

 others diverge from their origins. 5. They 

 lie in deep furrows on the surface of the brain, 

 and they leave the skull by several distinct 

 orifices. In many of these characters they are 

 more like portions of brain than nerves; and, 

 as Valentin observes, there is no other nerve 

 in the adult human body which shows its 

 origin as an immediate prolongation of the 

 central nervous mass so plainly as these do. 

 It was on account of these characters that the 

 olfactory nerves were regarded by the an- 

 cient anatomists as processes of the brain 

 (mamillary or papillary processes), through 

 the central canals in which they supposed 

 that the pituitary humour was carried from 

 the lateral ventricles to the nose, and air was 

 drawn into them by the nostrils. And al- 

 though this notion was derived from dissect- 

 ing the nerves of animals in which the trunks 

 remain hollow, yet their true nature was 

 doubted on the same grounds by many, even 

 after Willis had demonstrated their structure in 

 man.* 



In accordance with its numerous offices, the 

 nose receives, in addition to these, the nerves 

 of its peculiar sense, others for common sen- 

 sation, for the movements of its muscles, and 

 for the government, in some degree at least, of 

 the organic processes which are carried on in 

 it. Its sensitive and organic nerves are de- 

 rived from the internal nasal or ethmoidal 

 branch of the first or ophthalmic division of the 

 fifth, from the naso-palatine and numerous other 

 branches, from the spheno-palatine ganglion, the 

 nasal branches of the Vidian, palatine, anterior 

 dental, and infra-orbital nerves; all of which 

 are described under the title FIFTH PAIR OF 

 NERVES. Its motor nerves are supplied by 

 the facial or seventh pair [SEVENTH PAIR OF 

 NERVES]. 



Vessels of the nose. Its arteries are derived 

 from the ophthalmic, the iiiternal maxillary, 

 and the facial. The ophthalmic artery gives it 

 the anterior ethmoidal, which enters with the 

 ethmoidal nerve, the posterior ethmoidal, and 

 the nasal, which anastomoses near the angle of 

 the eye with the angular branch of the facial 

 artery. From the internal maxillary trunk the nose 

 and the adjacent cavities are supplied through 

 many branches, namely, the alveolar, which 

 sends branches into the antrum, the infra-or- 

 bitar, of which the terminal branches partly 

 supply the skin, the Vidian, anterior palatine, 

 pterygo-palatine, and spheno-palatine, each of 

 which, as it passes towards or through the canal 

 after which it is named, sends branches to the 

 mucous membrane of the adjacent part of the 

 nose or of the cavities opening into it. From 

 the facial artery branches are derived both 

 through the superior labial and from the trunk 

 itself. Indeed, the dorsal arteries of the nose 

 may generally be regarded as the termination 



* See Cloquet, and Metzger, 1. c., and S^rengel, 

 Histoire dc la Mcileciue, iv. p. t>9. 



