396 OPEEATIONS ON THE DIGESTITE APPABATUS. 



through it pass the testicular cord and the testicular blood ves- 

 sels, in the male, and the blood vessels of the mammse in the 

 female, as they emerge from the abdominal cavity. Situated on 

 one side of the prepubic region, it observes an oblique direction, 

 downward, backward, and from without inward, being formed 

 posteriorly by the crural arch, and anteriorly by the fleshy portion 

 of the small oblique muscle of the abdomen. Inferiorly it has 

 an opening called the inferior inguinal ring, which is made 

 through the aponeurosis of the great obHque, oval in shape, and 

 possessing two lips, edges or pillars, united together by two 

 commissicres. The lips, divided^ into anterior and posterior, are 

 formed by the fibres of the aponeurosis of the great oblique 

 muscle of the abdomen, and a few of the muscular fibres of the 

 small obUque, reinforced by some bands of the tunica abdominalis. 

 The commissures, divided into external and internal, result from 

 the union of the extremities of the two pillars. The superior 

 opening of the inguinal canal is known also as the peritoneal 

 or superior inguinal ring, and is situated in front of and directly 

 opposite the crural ring. It represents a single slit, subject to 

 dilatation, placed also between the crural arch and the small 

 oblique of the abdomen, and allovsdng on its inner border the pas- 

 sage of the anterior pudic or posterior abdominal artery, it sur- 

 rounds the neck, and forms the entrance of the vaginal sheath. It 

 is open in horses, and often in bovines also, and it allows a direct 

 communication between the cavity of the vaginal sac and that of 

 the peritoneum — undoubtedly a predisposing condition to hernias, 

 not to be overlooked. The testicular sac offers to our attention, 

 from the point of view from which we now consider it, an 

 entrance, or true infundibulum, overlapping the internal opening 

 of the inguinal ring or canal ; a necJc situated just below that ring, 

 a continuation of the infundibulum or entrance, and which at a 

 short distance from its origin offers a well marked contraction in 

 its diameter — this being the point where strangulation takes 

 place — a middle part, containing the spermatic cord; and a 

 bottom, or true cul-de-sac, where the testicles and the epididymis 

 are lodged. 



The special signification of the terms which have been else- 

 where and ah-eady employed to designate and classify the varie- 

 ties of form and manifestation characterizing different varieties of 

 hernia are of interest, and should not be lost sight of. They are 



