THE SI O?fA CH 1 273 



to Clendinning, is about four ounces and a half, and its capacity in the adult male 

 is five to eight pints. The stomach of a newborn child holds about one ounce. 



Alterations in Position. There is no organ in the body the position and connections of 

 which present such frequent alterations as the stomach. When empty, it lies at the back part 

 of the abdomen, some distance from the ventral abdominal wall, and is in the left hypochondriac 

 region and the left portion of the epigastric region. Its fundus is directed upward and backward 

 toward the Diaphragm. The long axis of the viscus is quite oblique. Its pyloric end is directed 

 toward the right, covered in front by the left lobe of the liver, and on a level with the first lumbar 

 vertebra. When empty and contracted the stomach assumes a more or less cylindrical form, 

 especially noticeable at its pyloric end, and resembles a piece- of thick-walled intestine. When 

 the stomach is distended, its surfaces become convex and the shape becomes pyriform, its long 

 axis being downward, forward, and to the right'. The greater curvature is elevated and carried 

 forward, so that the anterior surface is turned more or less upward and the posterior surface 

 downward, and the stomach is brought well against the anterior wall of the abdomen. Its 

 fundus expands and rises considerably above the level of the cardiac orifice; in doing this the 

 Diaphragm is forced upward, contracting the cavity of the thorax; hence the dyspnea complained 

 of as inspiration is impeded. The apex of the heart is also tilted upward; hence the oppression 

 in this region and the palpitation experienced in extreme distention of the stomach. The left 

 lobe of the liver is pushed toward the right. When the stomach becomes distended the change 

 in the position of the pylorus may be considerable; it is shifted to the right as much as two 

 inches from the median line, and lies under cover of the liver, near the neck of the gall- 

 bladder. In consequence of the distention of the stomach the pyloric antrum bulges in front 

 of the pylorus, concealing it from view, and causing it to undergo a rotation, so that its orifice is 

 directed backward. When the stomach is greatly distended its lower border may enter the um- 

 bilical and the left lumbar regions. During inspiration the stomach is displaced downward by 

 the descent of the Diaphragm, and it is elevated by the pressure of the abdominal muscles during 

 expiration. Pressure from without, as from tight lacing, pushes the stomach down toward the 

 pelvis. In fact, in the female, because of tight lacing, the body of the stomach may be to the left 

 side of the vertebral column and nearly vertical in direction, the pyloric portion being sharply 

 angled upward toward the pylorus, which lies underneath the liver. Besides the angulation, 

 the stomach may have a median constriction, and there may even be an hour-glass stomach. 

 In disease the position and connection of the stomach may be greatly changed, from the accumu- 

 lation of fluid in the thoracic cavity or abdomen, or from alteration in size of any of the surround- 

 ing viscera. ' 



Variations According to Age. In an early period of development the stomach is vertical, and in 

 the newborn child it is more vertical than later on in life, as owing to the large size of the liver 

 it is pushed over more to the left side of the abdomen, and the whole of the anterior surface is 

 covered by the left lobe of this organ. 



Interior of the Stomach. When examined after death, the stomach is usually 

 fixed at some temporary stage of the digestive process. A common form is that 

 shown in Fig. 995. If the viscus be laid open by a section through the plane of 

 its two curvatures, it is seen to consist of the two segments already described 

 viz., a large globular portion to the left, comprising the body and fundus, and the 

 tubular pyloric portion to the right. The mucous membrane lining the interior 

 is soft and velvety, red or reddish brown in the body and fundus, and of a pinkish 

 tinge at the pyloric end. It is thrown into numerous folds or rugae, chiefly longi- 

 tudinal in direction and most marked toward the pyloric end and along the greater 

 curvature. To the left of the cardiac orifice is the incisura cardiaca; the projec- 

 tion of this notch into the cavity of the stomach increases as the organ distends, 

 and has been supposed to act as a valve preventing regurgitation into the oesopha- 

 gus. In the pyloric portion are seen (a) the elevation corresponding to the 

 incisura angularis, and (6) the circular projection from the duodenopyloric con- 

 striction which forms the pyloric valve. The separation of the pyloric vestibule 

 from the pyloric canal is scarcely indicated, but the manner in which the pylorus 

 is invaginated into the duodenum is evident. 



The pyloric valve (valvula pylori} (Fig. 997) is formed by a reduplication of 

 the mucous membrane of the stomach, containing numerous circular fibres, which 

 are aggregated into a thick circular ring, the Pyloric Sphincter (m. sphincter pylori*); 

 some of the deeper longitudinal fibres turn in and interlace with the circular fibres 



