The bulbocavernosus is one of the perineum muscles in the human body. It is a superficial part of the muscular system, meaning it resides near the surface of the body. The bulbocavernosus in men is somewhat different than the muscle in women, but in both sexes it ensures waste is disposed from the urethra. Bulbocavernosus is the more traditional name of the muscle; later medical texts refer to the muscle as the bulbospongiosus.
In males, the muscle is located around the bulb of the penis, which is centered near the base of the organ. In females, the muscle is situated around the vestibular bulb in the internal part of the clitoris. The bulbocavernosus of both sexes is positioned in the center of the perineum and in front of the anus. It is comprised of two symmetrical sections united along a center line. The muscle contains an offshoot of the perineal nerve, which is itself an offshoot of the pundendal nerve, making it a vital muscle in experiencing sexual pleasure.
The muscle fibers of the bulbocavernosus are divergent and do not run parallel to one another. Their exact arrangement can be compared to the fine barbs of a feather. The fibers are positioned in a series of layers. The outermost layer is very thin, and the middle layers envelop either the penile or vestibular bulb.
The muscle plays an important role in the sexual functions of both sexes. In men, the muscle aids in maintaining an erection, facilitating healthy ejaculation, and intensifying orgasms. The front part of the bulbocavernosus narrows during an erection and exerts pressure on the deep dorsal vein of the penis, which aids in sustaining the erection. The nerves in the muscle are then stimulated by the movement of the penis.
In women, the muscle helps achieve a clitoral erection and increases the pleasure of orgasms. As in males, the conglomerations of nerves in the muscle are aroused by the appropriate movements, heightening sensation and pleasurable feelings. The bulbocavernosus also serves to close and clench the vagina.
Immediately after a member of either sex relieves his or her bladder, urine will still reside in the canal of the urethra. The fibers of the bulbocavernosus are involved in eliminating urine from this region. During urination, the fibers of the muscle are relatively inactive. Only toward the end of the process do the fibers move into action, ejecting lingering waste from the urethra canal.