396 OPERATIONS ON THE DIGESTITE APPAKATUS. 



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

 sels, in the male, and the blood vessels of the mamm?e in the 

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

 one side of the preiDubic 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 

 jDossessing two %:>s, edges or pillars, united together by two 

 commissures. The lii^s, 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 oblique, 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 stiperior inguiyial ring, and is situated in front of and dii-ectly 

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

 dilatation, placed also between the crural arch and the small 

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

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

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

 is open in horses, and often in bo\dnes also, and it allows a du-ect 

 commimication between the cavity of the vaginal sac and that of 

 the peritoneum — undoubtedly a predisj^osing condition to hernias, 

 not to be overlooked. The testicular sac ofi^ers 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 tieek situated just below that ring, 

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

 short distance from its origin ofi'ers a well marked contraction in 

 its diameter — this being the point where strangulation takes 

 place — a middle part, containing the sj^ermatic cord; and a 

 bottom, or true cul-de-sac, where the testicles and the ej)ididymis 

 are lodged. 



The special signification of the terms which have been else- 

 where and already 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 



