scrotum

For the obsolete dinosaur fossil name, see Megalosaurus#”Scrotum humanum”. The scrotum is an anatomical male reproductive structure that consists of a suspended sack of skin and smooth muscle that is dual-chambered, present in most terrestrial male mammals and is located under the penis. The left testis is lower than the right to avoid compression in the event of impact. The perineal raph is a small, vertical, slightly raised ridge of scrotal skin under which scrotal septum exists. It appears as a thin longitudinal line that runs front to back over the entire scrotum. The scrotum contains the external spermatic fascia, testes, epididymis, ductus deferens. Stream-lined, aquatic mammals such as whales and seals typically lack an external scrotum. It is an distention of the perineum and carries abdominal tissues some into its cavity including the testicular artery, testicular vein and pampinform plexus. In humans and some other mammals, the scrotum becomes covered with pubic hair at puberty. The scrotum is biologically homologous to the labia majora in females.