724 



NOSE. 



nearly equal portions, but of which the lower 

 part alone reaches to the anterior aperture. 



The posterior aperture of the nasal cavities 

 is quadrilateral. It is bounded below by the 

 palatine plates of the palate bones, with the 

 posterior nasal spine formed at their junction ; 

 on each side by the internal pterygoid plate of 

 the sphenoid bone ; and above by the alee of 

 the vomer and the body of the sphenoid bone. 

 The posterior edge of the vomer divides it into 

 two equal lateral parts. 



The space of which these are the apertures 

 is altogether irregular in its form, but each of 

 the halves into which it is divided by the sep- 

 tum may be described as having four walls or 

 boundaries, a superior, inferior, and two late- 

 ral. The superior wall or vault of each cavity 

 of the nose is formed in front by the posterior 

 surface of the nasal bone ; above and in the 

 middle by the inferior surfaces of the nasal 

 spine of the frontal, and of the cribriform plate 

 of the ethmoid bone; behind by the anterior 

 and inferior surfaces of the body of the sphe- 

 noid bone, and its turbinated bone, and by the 

 ala of the vomer. The anterior part of this 

 wall looks downwards and backwards, and 

 presents shallow branched grooves in which 

 brandies of the internal nasal nerve lie, and 

 one or more apertures through which one of 

 those branches and an artery or two pass. The 

 middle part of the wall is nearly horizontal, 

 and is perforated by many apertures for the 

 branches of the olfactory nerve, and for the in- 

 ternal nasal nerve ; the posterior part looks 

 downwards and forwards, and presents an 

 aperture leading into the sphenoidal sinuses. 



The lower wall or floor of the nasal cavity 

 is nearly horizontal ; it is concave transversely, 

 a little raised at each end, and narrower before 



Fig. 399. 



View of the outer wall of tlie nasal cavity on the riyht 



side. 



1, nasal bone; 2, frontal bone ; 3, frontal sinus; 

 4, sphenoidal sinus ; 5, palatine surface of the hard 

 palate; 6, edge of the pjlate bone ; 7, anterior edge 

 of the superior maxillary boue. 



than behind. It is formed by the upper sur- 

 faces of the palatine plates of the superior max- 

 illary and palate bones, and its inner border is 

 a little prolonged both behind and before upon 

 their nasal spines. Near its anterior border it 

 is perforated by the superior orifice of the 

 anterior palatine canal. 



The outer wall is the most complicated. 

 (Fig. 399.) If a vertical line be drawn down- 

 wards from the base of the nasal spine of the 

 frontal bone (a), it will have in front of it the 

 plain part of this wall, a slighty concave tri- 

 angular surface, formed by the ascending pro- 

 cess of the superior maxillary bone (6), and 

 presenting nothing but some shallow grooves 

 for bloodvessels and nerves. And, if a similar 

 line be drawn downwards from the front of the 

 body of the sphenoid bone (c), it will have 

 behind it another plane surface formed by the 

 internal pterygoid plate (ci). Between these 

 vertical lines there is a large quadrilateral sur- 

 face divided into three parts by the three tur- 

 binated bones, whose edges project in nearly 

 parallel and horizontal lines, at about equal 

 distances one above the other. At the upper 

 part of this surface and anteriorly is a thin 

 quadrilateral plate (e) belonging to the cellular 

 portion of the ethmoid bone, made very rough 

 by grooves and apertures which lodge branches 

 of the olfactory nerve. The anterior part of 

 this plate forms the inner wall of the anterior 

 ethmoidal cells ; the posterior part (f) is a 

 little curved outwards, and leaves a space 

 between its surface and the body of the sphe- 

 noid bone into which the sphenoidal sinus 

 opens. The lower border of this plate is con- 

 tinuous anteriorly with the inner surface of the 

 middle turbinated bone, and posteriorly has a 

 free margin which is slightly curled outwards. 

 From the form of this margin the plate is called 

 the superior turbinated bone, (cornet .S-W/H- 

 rieur ; oberxte Muschel;) and the space which 

 it here covers, and which is a kind of horizon- 

 tal channel between its outer surface and the 

 wall of the adjacent ethmoidal cells, is the 

 superior mcatus of the nose. Into this meatus 

 the posterior ethmoidal cells open, usually by 

 two or more orifices concealed by the turbinated 

 bone ; behind and a little below it is the 

 spheno-palatine foramen (/<), at which the nasal 

 branches from the spheno-palatine ganglion 

 and the spheno-palatine vessels enter the nose; 

 and yet further backward, and nearly opposite 

 the end of the superior turbinated bone, is the 

 opening into the sphenoidal sinuses. 



Below this upper plate, and continuous with 

 it anteriorly, is the inner surface of the middle 

 turbinated bone (g), another portion of the eth- 

 moid bone, (cornet inoyen; mittlere Muschcl. ) 

 It is larger than the superior, more convex on 

 its inner surface, and presents a free margin 

 through the whole extent of its lower border, 

 which is thick, and abruptly curled outwards, 

 and sometimes has cavities within it (sinuses 

 of Suntorini), communicating with the eth- 

 moidal cells. The inner surface of the bone is 

 deeply grooved and perforated by bloodvessels 

 and branches of the olfactory and naso-pala- 

 tine nerves. Of the grooves, those which lodge 



