20 SPRING-TIME SURGERY 



directed obliquely forward and outward in its 

 greater diameter. It is covered by a thin layer 

 of peritoneum, while its margins, the borders of 

 the great and small oblique muscles, are distin- 

 guished by their greater thickness and firmness. 

 This ring is located two to four inches upward, 

 outward and slightly forward from the external 

 abdominal ring. It is just opposite and very near 

 to the crural ring, and, by palpating outward 

 against the thigh, the operator easily recognizes 

 the pulsating femoral artery as it emerges from 

 the crural ring. 



In some cases the internal ring is unrecog- 

 nizable by palpation, but the determination of its 

 approximate location is nevertheless essential to 

 scientific cryptorchid castration. The recog- 

 nition of the ring is especially difficult in animals 

 previously operated upon unsuccessfully, and fol- 

 lowed by the formation of a large amount of 

 dense, cicatricial tissue. When the ring has been 

 recognized, if the operator will approximate his 

 thumb, index, and second fingers to constitute an 

 incomplete circle of one to two inches in diameter 

 and press the ends of the digits against the abdo- 



