The relationship between the testis and tunica vaginalis changes with age

Background/aim Anatomy of the testis and tunica vaginalis (TV) is taught to pediatric surgeons from adult postmortem material. Textbooks describe the testis as 'behind' the TV, but at pediatric orchidopexy it appears to be inside the TV. We aimed to study whether testis and TV anatomy changes with age. Methods After ethical approval, postmortem photographs and measurements of testis length, width, and mesenteric attachment length (mm) in 37 adults (22-92 years), one infant (4/12), and one fetus (19/52) were compared with intraoperative orchidopexies (x6) after opening TV (n = 4; 7/12-14 years). Testis length, area and perimeter and ratios for mesentery attachment were plotted against age. Results The fetal and pediatric testes were intraperitoneal with a mesentery (mesorchium), but after 50 years secondary adhesions between TV and testis obliterated the mesorchium, so in advanced age the testis appeared to be behind the TV. Discussion These results show that in childhood testes were 'intraperitoneal', but after 50 years of age the TV progressively shrinks and adheres to the testis, making it appear to be behind the TV. This difference between anatomical texts and childhood anatomy suggests that pediatric surgery may need anatomy texts that specifically highlight age differences.