Inguinal hernia in children

What it is

Inguinal hernias are a common disorder in children. They are commoner in males as the testis migrates from its location on the posterior abdominal wall down through the inguinal canal, and a patent processus vaginalis may persist and be the site of subsequent hernia development. In males the cause is a patent processus vaginalis, and in females a patent diverticulum of Nuck.

How it comes about is set out: the processus vaginalis is an invagination of parietal peritoneum that comes before the migration and descent of the testicles in males, and the same invagination occurs in females; this peritoneal extension normally becomes obliterated after birth; and failure of the processus vaginalis to close causes a congenital inguinal hernia.

What is inside the sac differs by sex: bowel or omentum in boys, and the ovary or fallopian tube in girls, protruding into a patent processus vaginalis along the inguinal canal. These are mostly indirect inguinal hernias, where the sac originates at the level of the deep inguinal ring lateral to the inferior epigastric vessels.

A congenital patent processus vaginalis is also the common cause of the indirect type in general, whose pathway runs through the deep ring into the canal and possibly into the scrotum, lateral to the inferior epigastric vessels. The direct type differs at every point: it comes through the posterior wall at Hesselbach's triangle, lies medial to the inferior epigastric vessels, and follows acquired weakness rather than a congenital cause. When a direct and an indirect sac are present together, the hernia is called pantaloon or saddle-bag and sacs are found on both sides of the vessels. By size the hernia is a bubonocele when the sac stops within the inguinal canal after entering the internal ring, funicular when the sac emerges out of the external ring and stops just above the testis, and complete scrotal when the processus vaginalis is patent throughout and continuous with the tunica vaginalis of the testis, which is a congenital hernia commonly seen in children. The indirect hernia originates in the deep inguinal ring, 1.25 cm above the midinguinal point, and often descends into the scrotal sac or the labia majora.