Bulbospongiosus Muscle

Bulbospongiosus muscle is one of the superficial muscles of perineum, covering the bulb of the penis and posterior portion of the corpus spongiosum.

Origin:

The bulbospongiosus muscle has slightly different origins in males and females. In males it arises from perineal body, midline raphe and inferior fascia of urogenital diaphragm. In females, the midline raphe is not involved in the origin of the muscle.

Insertion:

The insertion of the muscle is quite different in males and females. In males, the bulbospongiosus muscle is inserted into the dorsum and lateral borders of penile bulb. In females, it passes around the outside of vagina to insert into the dorsum of the clitoris.

Nerve supply:

In both males and females, the muscle is innervated by the deep (muscular) branch of the perineal nerve, which in turn is a branch of the pudendal nerve.

Blood supply:

Pudendal artery supplies blood to the muscle.

Action:

In males, the muscle contributes to erection, ejaculation and the feeling of orgasm. In addition, it also serves to compress the penile part of urethra and empty it of residual urine or semen.  In females it acts to close the vaginal canal. It also facilitates the ejection of clitoris and the feeling of orgasm.