290 THE ABDOMEN AND PELVIS 



commences on the fundus (p. 289), cuts the left costal margin 

 at the tip of the ninth costal cartilage, descends not infrequently 

 almost to the umbilicus, and then ascends to the pylorus (vide 

 infra) ; in the erect posture it descends to the umbilicus, and 

 sometimes to a lower level. Along the greater curvature, the 

 two layers of peritoneum which clothe the stomach pass down- 

 wards to form the greater omentum, and on the left side they 

 pass backwards to the spleen as the gastro-splenic ligament. 



The Lesser Curvature forms the upper or posterior border 

 of the stomach. It passes downwards and to the right from 

 the cardiac orifice to the pylorus, curving round the tuber 

 omentale of the liver. It can be mapped out on the surface by 

 a line, concave upwards and to the right, joining these two 

 points. In the erect posture this line becomes more nearly 

 J -shaped owing to the descent of the pylorus and the fixation 

 of the cardiac end of the stomach. Along the lesser curvature 

 the lesser omentum leaves the stomach and passes to the liver 

 and diaphragm. 



The distal or pyloric portion of the stomach includes the 

 pyloric antrum, the pyloric canal, and the pylorus. The pyloric 

 antrum is a secondary dilatation of the stomach and is placed 

 proximal to the pyloric canal. The latter is tubular in shape 

 and is about one inch long. It communicates with the duodenum 

 through the pylorus. 



With the body in the supine position and the stomach 

 moderately distended, the Pylorus lies on the transpyloric plane, 

 half an inch to the right of the middle line ; but when the erect 

 posture is adopted, it may sink down to the level of the third 

 lumbar vertebra. In Fig. 91, where the radiogram was taken 

 in the vertical position, the pylorus is seen at that level. At 

 a subsequent operation it was found that, with the change of 

 posture, it had ascended to the transpyloric plane. 



The anterior surface of the pylorus lies in contact with the 

 liver, which hides it from view when the abdomen is opened. 



The Position of the Stomach is subject to wide variations. 

 It is affected by (i) attitude, (2) respiration, (3) the tonus of the 

 anterior abdominal wall, and (4) its contents and those of the 

 small intestines and transverse colon. In addition, apart from 

 differences due to pathological conditions, there is a large range 

 of individual variation. 



When the body assumes the erect posture, the postero- 

 inferior surface of the stomach slides downwards and forwards 



