THE ABDOMEN 781 



vein being internal to the arter\', and (2) the femoral branch of the 

 genito-femoral nerve, which lies close to the outer side of the artery. 

 The part of this lacuna internal to the external iliac vein forms the 

 crural or femoral ring, which is closed by the septum femorale. 



STRUCTURE AND DEVELOPMENT OF THE ABDOMINAL 



VISCERA 



Structure of the Stomach. 



The wall of the stomach is composed of four coats — serous, 

 muscular, submucous, and mucous. 



The serous coat is formed by the peritoneum, which covers 

 every part of the organ except (i) along the great and small 



CEsophagus 



Longitudinal Muscniar 

 Layer 



s Pyloric Sphincter 



V Fig. 333. — Dissection showing the Muscular Layers of the Stomach. 



*s 



I curvatures, and (2) the uncovered trigone, situated on the posterior 



|, surface, below and a little to the left of the cardiac orifice. 



The muscular coat {muscidaris externa) is composed of plain 

 muscular tissue disposed in three layers external or longitudinal, 

 middle or circular, and internal or oblique. The external or longi- 

 titdinal fibres are continuous with the longitudinal fibres of the 

 oesophagus, and at the pyloric end of the stomach they are 

 continuous with the longitudinal fibres of the duodenum. 

 They are most abundant along the small curvature. The middle 



