ABDOMINAL CAVITY 



57 



The serous coat, derived from the peritoneal membrane, 

 can be best stripped off with the fingers. The subserous coat 

 is composed of a little areolar tissue which intervenes between 

 the muscular and serous strata. The branches of the two 

 vagi nerves can now be followed, as they spread out upon 

 both surfaces of the stomach. 



The muscular coat consists of involuntary or unstriped 

 muscular fibres, and these are disposed in three incomplete 

 layers each layer being distinguished by the direction of its 

 fibres. The stratum longi- 

 tudinale (O.T. external 

 layer) is composed of fibres 

 which run for the most part 

 in the longitudinal direction. 

 The longitudinal fibres of 

 the oesophagus, on reaching 

 the cardiac orifice, radiate 

 over the stomach in all 

 directions, but more par- 

 ticularly along the lesser 

 curvature, and they dis- 

 appear (with the exception, 

 perhaps, of some on the 

 lesser curvature) before 

 they reach the pyloric part 

 of the organ. On the body 

 of the stomach a new and 

 independent set of longi- 

 tudinal fibres take origin, 

 and these gradually form 

 a continuous layer which 



gains in strength and thickness as it sweeps onwards towards 

 the pylorus. The stratum circulare (O.T. middle layer) is 

 composed of circular fibres, which are continuous with the 

 more superficial circular fibres at the lower end of the 

 oesophagus. They do not form a continuous coating for 

 the stomach (Birmingham). Beginning as a series of loops 

 immediately to the right of the cesophageal opening, they 

 gradually increase in length as the layer is followed 

 towards the pylorus, and soon they completely encircle 

 the organ and form a continuous stratum. No fibres of 

 this layer encircle the fundus. At the pylorus the circular 



stomach. 



