SOME POINTS IN THE ANATOMY OF THE DIGESTIVE SYSTEM. 39 



very oblique, or almost vertical, and its abdominal opening 

 looks forwards and to the left, but only slightly downwards. 

 Above and in front, where it is bounded either by the posterior 

 ■edge of the central tendon, or by a few decussating fibres of the 

 muscular portion which meet behind the tendon, the oesophageal 

 orifice has practically no length, and consequently the oesophagus 

 here passes into the abdominal cavity immediately after leaving 

 the thorax. At the sides and below, on the other hand, the decus- 

 sating bands from the two crura, which embrace the orifice, are 

 so arranged that they turn a flat surface, not an edge, towards 

 the opening, and thus behind and at the sides the orifice or 

 •canal is of some length, and on these aspects there is a portion 

 of the tube in contact with the diaphragm for a distance of 1 to 

 1| cm. But this contact takes place not around a horizontal 

 line, but in a very oblique plane, corresponding to that of the 

 orifice. On the whole, it is perhaps more satisfactory not to 

 describe a separate diaphragmatic portion, but to say that the 

 oesophagus pierces the diaphragm very obliquely, and that at 

 the sides and behind it is in contact with the walls of the orifice 

 for a distance of ^ inch or more. 



The oesophagus in passing through the orifice is connected to 

 its boundaries by a considerable amount of strong connective 

 tissue, but it is extremely difficult, or impossible, to demonstrate 

 any direct naked-eye connection between the oesophageal 

 muscvilar fibres and those of the diaphragm. 



The anterior or right boundary of the oesophageal orifice, 

 formed of fibres derived from both crura of the diaphragm, is 

 very strongly developed and prominent, and usually lies in the 

 oesophageal groove, on the back of the left lobe of the liver, 

 which groove is rarely due, I believe, to the pressure of the 

 oesophagus itself. 



The abdominal portion of the oesophagus is very short, for 

 immediately after piercing the diaphragm the tube expands into 

 the stomach. However, when the empty stomach is drawn 

 forcibly downwards, a portion of the front and left side of the 

 tube, about half an inch in length (l-l'o cm.), is seen, to which 

 the above term is applied. This part is covered with peritoneum 

 derived from the great sac in front and on the left, whilst its 

 right and posterior surfaces are imcovered. It is generally 



