Structurally, the scrotum is actually segregated into two distinct segments. The compartments are created length wise and maintain their separation via a fibrous scrotal septum. This internal segregation helps to protect testes from being infected or damaged via disease of the other one. To help protect against damage, the left testis descends farther down than the right to avoid compression in the event of impact. The surface of the testes provides evidence of the scrotal septum with the appearance of a longitudinal line that runs front to back over the entire testis, with the exception of where it attaches to the body. This ridge is referred to as perineal raphe.
Get to know your scrotum, fellas!