THE ORGANS OF DIGESTION. 



to the vertebral column. Some peritoneal folds also aid, as the lig. phrenico- 

 gastricuni connecting the cardia to the diaphragm. To the right this joins the 

 lesser omentum, which is very thin, but farther to the right is the strong lig. 

 hepato-duodenale, which confines the pylorus. The great omentum and gastro- 

 splenic afford no fixation to the stomach. The spleen has no firmness of position, 

 so the stomach gains nothing by that attachment. The great omentum hangs 

 free in front of the intestines, and could only modify the position of the stomach 

 when caught in a hernia. 



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

 which present such frequent alterations as the stomach. During inspiration it is displaced 

 downward by the descent of the Diaphragm, and elevated by the pressure of the abdominal 

 muscles during expiration. Its position in relation to the surrounding viscera is also changed 

 according to the empty or distended state of the organ. When empty it lies at the back part 

 of the abdomen, some distance from the surface. The left lobe of the liver covers it in front. 

 and the under surface of the heart rests upon it above and in front, being separated from it by 

 the left lobe of the liver, besides the Diaphragm and pericardium. This close relation between 

 the stomach and the heart explains the fact that in gastralgia the pain is generally referred to 

 the heart, and is often accompanied by palpitation and intermission of the pulse. When f/if 

 stomach is distended the greater curvature is elevated and carried forward, so that the anterior 

 surface is turned upward and the posterior surface downward, and the stomach brought well 

 against the anterior wall of the abdomen. 1 The Diaphragm at the same time is forced upward, 

 contracting the cavity of the chest ; hence the dyspnoea complained of, from inspiration being 

 impeded. The heart is also displaced upward ; hence the oppression in this region and the 

 palpitation experienced in extreme distention of the stomach. Pressure from vrim&ut, as from 

 tight lacing, pushes the stomach down toward the pelvis. In disease also the position and con- 

 nections of the organ may be greatly changed, from the accumulation of fluid in the chest or 

 abdomen or from alteration in size of any of the surrounding viscera. 



Structure. Its walls are composed of four coats named in order serous, mus- 

 cular, submucous or areolar, and mucous. 



The serous coat, peritoneum, is thin, smooth, and moist, allowing some -mo- 

 bility of the organ. It encloses the stomach between two layers, derived from 



the lesser omentum. Where the 

 layers come upon the surface and 

 leave it again greater and lesser 

 curvature they lie loosely and 

 leave a small interspace, in which 

 blood-vessels, nerves, lymph-vessels 

 and glands, take their course. Else- 

 where the serous layer is held so 

 tightly by subserous tissue to the 

 muscular coat that it can only be 

 removed artificially in small bits. 

 There is a small posterior area 

 near the cardia not covered by 

 peritoneum which touches the dia- 

 phragm. 



Musculature. Three sets of 

 unstriated muscular tissue are here 

 included longitudinal, circular, 

 and oblique. Their purpose is to 

 set the stomach contents in motion, 

 to push them on, and to empty 

 glandular secretion. 



The external or Ionfii1u<lil 

 layer is very incomplete and is 

 directly continuous Avith the longitudinal fibres of the oesophagus (Fig. 627). 

 There is a connected layer on the outer side of the cardia, from which fibres 



1 This is denied by Dr. Lesshaft of St. Petersburg, who states that " if the stomach is enlarged, 

 no one part can be alone displaced, but all parts are equally moved by the distention" (Lancet, 

 March 11, 1882, p. 406). 



FIG. 627. The external muscular coat of the stomach. 

 (Luschka.) 1. (Esophagus. 2. Cardia. 3. Fundus. 4. Pars 

 pylorica. 5. Lig. pyloricum. 6. Sulcus pyloricus. 7. Lesser 

 curvature. 8. Greater curvature. 9. Antrum duodcui. 



