158 ANATOMY FOR NUKSES. [CHAP. XIV. 



end turned upwards, and its constricted end downwards to 

 end in the O3sophagus. It is about four and a half inches 

 long, and lies behind the nose, mouth, and larynx. Above, it 

 is connected with the base of the skull, and behind, with the 

 cervical vertebrae ; in front and on each side are apertures 

 which communicate with the nose, ears, mouth, and larynx. 



Of these apertures there are seven : two in front above, lead- 

 ing into the back of the nose, the posterior nares ; two, one on 

 either side above, leading into the Eustachiari tubes, which com- 

 municate with the ears ; one midway in front, the fauces ; and 

 two below, one opening into the larynx and the other into the 

 oesophagus. The mucous membrane lining the pharynx is well 

 supplied with glands, and at the back of the cavity there is a 

 considerable mass of lymphoid tissue. The muscular tissue in 

 the walls of the pharynx is of the striped variety, and when the 

 act of swallowing is about to be performed the muscles draw 

 the pharyngeal bag upwards and dilate it to receive the food ; 

 they then relax, the bag sinks, and other muscles contracting 

 upon the food, it is pressed downwards and onwards into the 

 oesophagus. 



The oesophagus or gullet. The oesophagus is a comparatively 

 straight tube, about nine inches long, extending from the 

 pharynx, behind the trachea, and through the diaphragm, to 

 its termination in the upper or cardiac end of the stomach. 

 The muscular fibres in the walls of the oesophagus are arranged 

 in an external longitudinal and in an internal circular layer. 

 The mucous membrane is disposed in longitudinal folds which 

 disappear upon distension of the tube. The mucous mem- 

 brane in the mouth, pharynx, and oesophagus is covered for 

 the most part by stratified epithelium. 



The stomach. The stomach is the most dilated portion of 

 the alimentary canal. It is curved upon itself, so that below it 

 presents a long, rounded outline, called the greater curvature, 

 and above a constricted, concave outline, called the lesser 

 curvature. 



It is placed transversely in the abdominal cavity, immediately 

 beneath the diaphragm, the larger expanded end lying in con- 

 tact with the spleen, and the smaller end under the liver. The 

 stomach has necessarily two openings : the one leading into the 

 oesophagus is usually termed the cardiac aperture; the other, 



