STKUCTUEE OF THE STOMACH. 



1175 



the cardia, and pass downwards and to the left on both surfaces. Further to the right 

 these looped fibres are succeeded by circles which surround the organ completely. Traced 

 towards the narrow end of the stomach, the circular bundles grow thicker, and at the 

 pylorus they undergo a further, in- 

 crease, giving rise to the pyloric 

 sphincter which surrounds the orifice 

 as a thick muscular ring. 



The fibrce obliquce, forming the 

 inner layer, consist of fibres which 

 are arranged on the fundus and ad- 

 jacent parts of the stomach, in much 

 the same manner as those of the 

 middle layer are on the body and 

 pyloric part of the organ (Fig. 926, 

 C). They are continuous above with 

 the deeper circular fibres of the in- 

 ferior end of the oesophagus, and form 

 U-shaped bundles which loop over 

 the stomach immediately to the left 

 of the cardia, and run very obliquely 

 i downwards and to the right for a 

 considerable distance on both surfaces 

 of the organ. These looped fibres, 

 as they pass to the left, gradually 

 become less oblique, and finally form 

 circles which surround the wide end 

 of the stomach completely, even as 

 far as the summit of the fundus. 

 The oblique fibres can be most readily 

 shown by removing the circular fibres 

 on either surface below the cardia. 

 When traced towards the right, they 

 will be found to terminate by turning 

 down and joining the fibres of the 

 circular layer. 



Tela Submucosa. The sub- 

 mucous coat is a layer of strong but 

 loose connective tissue, which lies 

 between and unites the muscular and 

 mucous coats (Fig. 924). It is more 

 loosely attached to the muscular and 

 more closely to the mucous coat, and 

 it forms a bed in which the vessels 

 and nerves break up before entering 

 the mucous membrane. 



Tunica Mucosa. If examined in 

 the fresh state soon after death, the 

 mucous coat is of a reddish -gray 

 colour and of moderate consistence. 

 When examined some time after 

 death, the colour turns to a darker 

 gray, and the whole membrane be- 

 comes softer and more pulpy. It is 

 thicker (over 2 mm.) and firmer in 

 the pyloric than in the cardiac part, 

 and is thinnest at the fundus, where it often shows signs of post-mortem digestion. 

 When the stomach is empty all three outer coats, which are extensile, contract ; whilst 

 the inextensile mucous coat, as a result of its want of elasticity, is thrown into 

 numerous prominent folds or rugce, which project into the interior and, as it were, occupy 

 the cavity of the contracted organ. These are, in general, longitudinal in direction, 

 ith numerous cross branches, and they are largest and most numerous along the 

 greater curvature. They disappear when the stomach is distended. 



When the surface of the mucous coat is examined in a fresh stomach, it_is seen to 



FIG. 926. THE THREE LAYERS OP THE MUSCULAR COAT OP 

 THE STOMACH. A, External or longitudinal layer ; B, 

 Middle or circular layer ; C, Internal or oblique layer. 

 a, Longitudinal fibres of oesophagus ; b, Superficial circular 

 fibres of oesophagus passing into circular fibres of stomach 

 in B ; c, Deep circular fibres of oesophagus passing into 

 oblique fibres of stomach in C ; d, Oblique fibres forming 

 rings at the fundus ; e, Submucosa. 



