74 SURGICAL APPLIED ANATOMY. [Chap. vi. 



between the second bicuspid teeth of either side. 

 The soft parts connecting the upper lip and nose to 

 the bone are divided without damaging the skin, and 

 the flap is dissected up until the nares are sufficiently 

 exposed. 



The posterior nares. If a little mirror, 

 somewhat similar to that used in laryngoscopy, be 

 cautiously introduced behind the soft palate through 

 the mouth, and illumined from the mouth, the following 

 parts may, under favourable circumstances, be seen : 

 the posterior nares, the septum, the, middle and 

 inferior turbinated bones, the Eustachian tube, and 

 the mucous membrane of the upper part of the 

 pharynx. 



This mode of examination is very difficult to carry 

 out, and is known as posterior rhinoscopy. The parts 

 just named can all be felt by the finger introduced 

 behind the soft palate through the mouth. The 

 posterior nares are often plugged to arrest severe 

 bleeding from the nose, and in order to cut a proper 

 sized plug it is desirable to bear in mind the dimen- 

 sions of the apertures. Each aperture is of regular 

 shape, and measures about half an inch transversely 

 by one and a quarter inches in the vertical direction 

 in a well-developed adult skull. 



As regards the nasal cavities generally, it is 

 well to note that the floor is wider at the centre 

 than at either end, that the vertical diameter is 

 greater than the transverse, and is greatest also about 

 the centre of the fossae. Forceps introduced into the 

 nose, therefore, are most conveniently opened if 

 opened vertically. 



From a reference to the relations of the nasal 

 fossce, it will be understood that inflammation of the 

 lining membrane (coryza) may extend to the pharynx 

 via the posterior nares ; may extend up the Eusta- 

 chian tube and cause some deafness ; may reach the 



