STOMA( 



Component Parts of the Stomach. A plane passing through the incisura angularis on the lesser 

 curvature and the left limit of the opposed dilatation on the greater curvature divides the stomach 

 into a left portion or body and a right or pyloric portion. The left portion of the body is known 

 as the fundus, and is marked off from the remainder of the body by a plane passing horizon- 

 tally through the cardiac orifice. The pyloric portion is divided by a plane through the sulcus 

 intermedius at right angles to the long axis of this portion; the part to the right of this plane 

 is the pyloric antrum (Fig. 1046). 



Antrum cardiacwm 



Incisura angularis 3 



Pylo roduodenal 

 opening 



Pyloric antrum 

 Sulcus intermedius 



Pyloric part 



FIG. 1046. Outline of stomach, showing its anatomical 

 landmarks. 



FIG. 1047. Diagram showing shape and position 

 of empty stomach. Erect posture. (Hertz.) 



If the stomach be examined during the process of digestion it will be found divided by a 

 muscular constriction into a large dilated left portion, and a narrow contracted tubular right 

 portion. The constriction is in the body of the stomach, and does not follow any of the 

 anatomical landmarks; indeed, it shifts gradually toward the left as digestion progresses, i. e., 

 more of the body is gradually absorbed into the tubular part (Figs. 1047, 1048, 1049). 



1048. Diagram showing shape and position of 

 moderately filled stomach. Erect posture. (Hertz.) 



FIG. 1049. Diagram showing shape and position of 

 distended stomach. Erect posture. (Hertz.) 



Position of the Stomach. The position of the stomach varies with the posture, with the 

 amount of the stomach contents and with the condition of the intestines on which it rests. In 

 the erect posture the empty stomach is somewhat J-shaped; the part above the cardiac orifice 

 is usually distended with gas; the pylorus descends to the level of the second lumbar vertebra 

 and the most dependent part of the stomach is at the level of the umbilicus. Variation in the 

 amount of its contents affects mainly the cardiac portion, the pyloric portion remaining in a more 

 or less contracted condition during the process of digestion. As the stomach fills it tends to 

 expand forward and downward in the direction of least resistance, but when this is interfered 

 with by a distended condition of the colon or intestines the fundus presses upward on the liver 

 and diaphragm and gives rise to the feelings of oppression and palpitation complained of in 

 such cases. His 1 and Cunningham 2 have shown by hardening the viscera in situ that the con- 

 tracted stomach has a sickle shape, the fundus looking directly backward. The surfaces are 

 directed upward and downward, the upper surface having, however, a gradual downward slope 

 to the right. The greater curvature is in front and at a slightly higher level than the lesser. 



1 Archiv fur Anatomic und Physiologic, anat. Abth., 1903. 



2 Transactions of the Royal Society of Edinburgh, vol. xlv, part i. 



