The bulbospongiosus is a muscle found in the superficial perineal pouch which covers the bulb of the penis in males and the bulb of the vestibule in females.
- origin: median raphe and perineal body
- insertion: dorsum of penis/clitoris, perineal membrane
- innervation: pudendal nerve
- blood supply: perineal artery
In men, the bulbospongiosus arises from both the medial raphe and perineal body. Some of these fibers travel laterally to attach to the perineal membrane. However, the majority of fibers act to wrap around the bulb and the corpus spongiosum to attach to the dorsal side of the penis.
In females, the bulbospongiosus arises from the perineal body but are distinctly separated on each side. Fibers then travel to cover the vestibular bulbs and greater vestibular glands.
The bulbospongiosus acts to expel remaining urine from the urethra after the bladder has completed its emptying. In males it also aids in the final stages of erection by compressing the veins within the bulb of the penis to maintain tumescence.
In females it constricts the vaginal orifice and aids in expression of the greater vestibular glands. It also contributes to erection of the clitoris in a similar manner to penile erection described above.