Testicular descent involves 2 phases: intra-abdominal and extra-abdominal (Hughes ,2008). During the intra-abdominal phase, the testis originating at the urogenital ridge, is attached to the diaphragm by the craniosuspensory ligament, its regression results in transabdominal migration of the testis between 8 and 15 weeks …show more content…
The second phase occurs between 25 and 35 weeks of gestation. The testis descends from its intra-abdominal location through the inguinal canal, drawing with it an extension of the lining peritoneum, which defines the processus vaginalis guided by the gubernaculum.( Skandalakis, …show more content…
The exact cause of the obliteration of the processusvaginalis is still unknown, but some studies reported that calcitonin gene-related peptide (CGRP), released from the genitofemoral nerve, may have a role in the fusion( Al Shareef , 2007). The prevalence of PPV is highest during infancy and declines with age(Osifo, 2008). The processus vaginalis typically obliterates around the 36th and 40th week of gestation. It is thought that 40 % close in the first few months after birth and by age 2 years an additional 20 % closes( Kokorowski, 2014).
Failure of luminal obliteration to occur, the patent processus vaginalis (PPV), which is a ready-made sac is present where abdominal contents may herniate(Rekky and Larsen, 2012). Even when the processus vaginalis is patent, the entrance may be adequately covered by the internal oblique and transverse abdominal muscles, preventing escape of abdominal contents. Failure of fusion can result not only in an inguinal hernia, but also in a communicating or noncommunicating hydrocele (Kaneda et al.,