THE STOMACH. 



1005 



stream outward in all directions with unequal lengths. They are thickest along 

 the lesser curvature. At the fundus and anterior and posterior walls there are 

 only a few delicate bundles which seem to pass deeply between the circular fibres. 

 The substantial longitudinal layer is united at the pylorus, where it is firmly 

 bound to the serous coat and wholly covers the circular layer. To this layer 

 belong the tigamtnt'i. />///"//</. This layer passes over the pylorus to the duode- 

 nal wall. The longitudinal layer stands in closest relation to the apertures of 

 the stomach. 



Circ itl'.tr fibres cover the whole length of the stomach in an uninterrupted 

 layer, but they are not everywhere collected with the same thickness and strength 

 (Fig. 628). They are fewest on 

 the fundus. where there is a sort 

 of whorl. They pass along the 

 stomach in circles at right angles 

 to its axis, and become thickest 

 at the pylorus, where they form 

 the sphincter pyloricus. On the 

 margin of the duodenum they 

 abruptly cease. Above they seem 

 connected with the circular coat 

 of the O2sophagus. By this set 

 the peristaltic movements of the 

 stomach are produced, carrying 

 the contents to the pyloric end, 

 where is experienced a strong 

 compression and after that a re- 

 laxation of the antrum pylori- 

 cam and of the pylorus, and 

 then the longitudinal fibres can 

 exercise their expulsive strength 

 on the whole circumference. 



The oblique lib res. like the longitudinal, form an imperfect layer. They lie 

 under the circular layer, and are thought to be derived from it. They can best 

 be seen when the stomach is turned inside out and the mucous membrane is 

 removed. This group is said to have no counterpart in any region of the digest- 

 ive tract. They are not believed to represent the ring fibres of the oesophagus. 

 They form a loose layer to the left of the cardia and pass superiorly and poste- 

 riorly toward the greater curvature. The upper edge of these fibres forms a 

 raised ligamentous strip on either side of the lesser curvature, about a finger's 

 breadth below it ; this goes in a flat curve (seen on inner surface of stomach) from 

 the left of the cardia on both sides toward the portio pylorica. At the apex of 

 the fundus and toward the greater curvature the fibres grow smaller and paler. 

 The bundles are apt to split into a sort of wicker-work, leaving longitudinal 

 clefts. Delicate fibres run from these to the submucosa and to the circular 

 fibres 



These fibres seem able to bring nearer together the cardia and pylorus, the 

 greater and lesser curvatures, and also the contiguous surfaces of the anterior 

 and posterior walls, resulting in the function of the pharyngeal groove in rumi- 

 nants. A sort of half canal is formed along the lesser curvature, where fluid 

 could be sent directly from oesophagus to pylorus or various juices could be sent 

 in the opposite direction. 



The mbmucmu <->:.it consists of loose, filamentous, areolar tissue, connecting 

 the mucous and muscular layers, thus allowing free movement to the former. It 

 supports the blood-vessels previous to their distribution to the mucous membrane. 

 The rugre of the stomach involve the mucous and submucous coats. 



The mucous membrane is thick, its surface smooth, soft, and velvety. In the 

 fresh state it is of a pinkish tinge at the pyloric end, and of a red or reddish- 



FIG. 6-28. Musculature of the stomach from within. The 

 stomach has been turned inside out. Circular and oblique 

 fibres. (Luschka.) 1. (Esophagus. 2. Antrum duodeni. 3. Cir- 

 cular fibres. 4. Oblique fibres. 



