DISSECTION OF THE ABDOMEN. 339 



fibres course along the great curvature and across the right sac, some 

 of these being continued on to the duodenum. The middle or circular 

 stratum is composed of fibres that are for the most part disposed at 

 right angles to the long axis of the stomach, though some of those 

 belonging to the left sac have a somewhat oblique direction. They 

 form a thick ring of fibres around the pyloric orifice — the pyloric ring. 

 The internal or oblique stratum is represented by only a few strands of 

 fibres on the right half of the stomach, but it forms a thick layer in the 

 wall of the left sac. It is especially strong immediately to the left 

 of the oesophageal orifice, from which point its fibres diverge to the 



The Oesophageal Orifice as seen from the Interior of the Stomach, after removal 

 of the mucous and submucous coats. 



1. (Esophageal orifice; 2. Middle or circular muscular fibres; 3 and 4. The limbs of the horse- 

 shoe arrangement of the inner or oblique muscular fibres ; 5. Fibres of the middle or circular 

 stratum joining the anterior limb of the horse-shoe fibres. 



anterior and posterior walls of the stomach, in the form of two thick 

 bands which leave between them, at the lesser curvature, a considerable 

 area over which the middle or circular stratum comes into contact with 

 the submucous coat. Those fibres in proximity to the oesophageal 

 orifice may be likened to a horse shoe, which embraces the end of 

 the gullet to the left and before and behind, while to the right the 

 orifice is embraced by the circular fibres. The two sets of fibres 

 therefore suffice to form a strong sphincter, which is the more 

 efficient since a number of the circular fibres immediately to the 

 right of the oesophageal orifice are continued into the anterior limb 

 of the horse-shoe arrangement of the oblique fibres (Fig. 43). 



3. The Submucous Coat is composed of areolar connective-tissue, in 

 which the blood-vessels ramify before they pass into the next coat. 



