[SUMAN-SAJAN]

The most common groin hernia, the indirect inguinal hernia is a type of inguinal hernia which protrudes through the inguinal ring and is ultimately the result of the failure of embryonic closure of the internal inguinal ring after the testicle passes through it. In the fetus, the peritoneum gives a coat to the testicle as it passes through this ring, forming a temporary connection called the processus vaginalis. In normal development, the processus is obliterated once the testicle is completely descended. The permanent coat of peritoneum that remains around the testicle is called the tunica vaginalis. The testicle remains connected to its blood vessels and the vas deferens, which make up the spermatic cord and descend through the inguinal canal to the scrotum.

The internal inguinal ring, which is the beginning of the inguinal canal, remains as an opening in the internal oblique muscle, which forms the muscular outer wall for the spermatic cord. When the opening is larger than necessary for passage of the spermatic cord, the stage is set for an indirect inguinal hernia. The protrusion of peritoneum through the internal inguinal ring can be considered an incomplete obliteration of the processus. A hernia occurs when intra-abdominal contents, commonly including preperitoneal fatty tissues, abdominal fluid if present, the peritoneum itself, and eventually omentum and intestines, traverse the ring to enter the inguinal canal. As time passes, the hernia contents may enlarge, extend the length of the canal, and even exit the canal through the external inguinal ring, an opening in the external oblique fascia, into the scrotum.

A second means of indirect inguinal hernia formation in the spermatic cord is a failure of the processus vaginalis to close properly.


FROM WIKIPEDIA