TAN i 



KELATIONS AND CONNEXIONS OF THE STOMACH. 1173 



/eneral increase in length which takes place during distension, the pylorus is 

 r xtoved a variable distance to the right beneath the quadrate lobe of the liver, 

 ind at the same time the long axis of the whole organ becomes much more 

 )blique, running forwards, downwards, and to the right. Finally there is 

 leveloped a special dilatation of- the pyloric part, known as the antrum pyloricum, 

 ,vhich in extreme distension is carried so far to the right that it may even reach 

 }0 the hypochondrium. 



Shape and Position of the Stomach as seen by X-Ray Examination. Examination 

 of the stomach by means of X-rays after a " bismuth meal " has given important 

 .uformation about the shape and position of the stomach in the living, and about 

 ihe changes which occur as the stomach fills and empties. 



These examinations corroborate, in great part, the conclusions which have been 

 irrived at by the study of formalin specimens so far as the shape of the stomach, 

 ind its division into parts, is concerned. In regard, however, to the position and 

 lirection of the stomach, X-rays show that the stomach in the living, and especially 

 .n the erect attitude, is more vertical than it is after death, and when the body 

 3 examined in the horizontal position. In the upright position, in fact, the long 

 ixis of the organ appears to be nearly vertical. The general shape and position 

 )f the stomach in the vertical position, moderately distended, is shown in Fig. 923. 

 From this it will be seen that not only is the body of the stomach nearly vertical, 

 Dut that the greater curvature reaches down to the umbilicus, and may descend 

 3ven beyond it. The pyloric part is directed upwards, as well as backwards, and 

 :he pylorus is not usually the lowest point of the stomach. 



The other anatomical features of the stomach described above are well brought 

 )ut. Thus the fundus is a hemispherical dome, lying to the left of the terminal 

 portion of the oesophagus, and continuous in outline with the body of the stomach. 

 It usually contains gas, and appears translucent to X-rays. The body is of uniform 

 Dutline, and the pyloric part is marked off from it by the incisura angularis, on 

 ihe lesser curvature. Further, the pyloric part shows division into pyloric antrum 

 md pyloric canal. The incisura angularia and sulcus intermedius are distinct. 



The position of the stomach is greatly influenced by attitude and by the con- 

 lition of the abdominal muscles. Contraction of the abdominal muscles can elevate 

 ]he stomach from 5 to 13 cm., or 2 to 5 inches, and the change from the horizontal 

 ]0 the erect attitude alters the height of the inferior border from 2 to 10 cm. This 

 sinking which occurs in the alteration from the horizontal to the erect attitude, 

 iccounts largely for the differences found between the stomach seen in the post- 

 mortem room or on the operating table and the stomach displayed by means of 

 X-rays. Thus, if the stomach figured on p. 1167 be considered fixed at the cardiac 

 3nd, and somewhat fixed at the pylorus, and the pyloric antrum and greater 

 iurvature should sink downwards, the shape, as seen from the front, would closely 

 resemble the X-ray appearances found often in the living. 



The empty stomach is a contracted tubular organ, except at the fundus, where 

 it appears to be always dilated. When food is taken, when the individual is 

 standing or sitting, it runs down to the point where the gastric walls are in contact 

 with one another. The distal portion of the stomach dilates for some distance, or 

 it least as far as the pyloric canal. 



As the stomach becomes filled the whole of the body of the organ becomes 

 lilated, but the fundus and cardiac portion more particularly so, and these two latter 

 regions act as a storehouse. 



There is no definite division of this portion from the remainder of the stomach 

 by a permanent sphincter, but the peristaltic waves of contraction begin about the 

 middle of the organ, and form a fleeting constriction between the two parts. 



As peristalsis goes on, the tubular pyloric part relaxes somewhat. The waves 

 3f peristalsis here become so deep as to divide this portion into chambers. The 

 food substances are forced through the pylorus by successive waves of peristalsis, 

 and in the form, usually, of jets which impinge against the posterior aspect of 

 the duodenal wall. 



Should there be undigested masses, the pyloric valve relaxes to allow them also 

 to pass into the duodenum. 



