Bulbospongiosus Muscle

In males, the bulbospongiosus muscles are united and surround the base of the penis. They assist in emptying the urethra. In females, these muscles are separated in the middle by the vagina and act to constrict the vaginal opening. They can also retard the flow of blood into veins, which help to maintain an erection in the penis of the male and the clitoris of the female.