Bulbospongiosus (bulbocavernosus) muscle in men: where it is and what it does

This is the close-up. For the whole pelvic floor, layer by layer, see our guide to male pelvic floor anatomy. For the deeper muscle most people mean by "PC muscle", see what is the PC muscle.

What the bulbospongiosus is

Your pelvic floor has layers. The outer one, at the front, holds two muscles: the bulbospongiosus and the ischiocavernosus.¹ Together with the bulb and the crura of the penis, they make up the root of the penis.⁴

The bulbospongiosus is a striated muscle,³ the same kind as the muscles in your arms and legs, which you can tighten on purpose.

Bulbospongiosus or bulbocavernosus?

They're the same muscle. Bulbocavernosus is the older name, and you'll still see it in research papers and some textbooks. One StatPearls anatomy chapter uses both names for it.³

Where it sits in men

• In the superficial perineal space, the most superficial layer of the pelvic floor, between your scrotum and your anus, along with the ischiocavernosus and the transverse perineal muscle.²
• Over the bulb of the penis. In men, the bulbospongiosus covers the bulb of the penis.²
• Across the pelvic outlet, where it meets the superficial transverse perineal muscles.⁴
• Anchored at the back to the perineal body, the point where several pelvic floor muscles and their connective tissue meet. In men it has two matching halves, joined by a thin tendon down the middle.³
• Nerve supply: muscular branches of the perineal nerve, which also supply the ischiocavernosus and the superficial transverse perineal muscles.²

What it does

Men have a pelvic floor too. Two of its muscles sit at the base of the penis: squeezing them raises the pressure inside an erect penis, and they contract in rhythm during ejaculation. Erections start with blood flow, not with these muscles.^5,6,7

Those two muscles are the bulbospongiosus and the ischiocavernosus. Like the rest of the pelvic floor, they work as a team: an NHS physiotherapy leaflet lists the jobs of the male pelvic floor as bladder control, bowel control, sexual function, stabilising the pelvis and supporting the pelvic organs.¹¹

Its neighbours: the ischiocavernosus and the PC muscle

When people say "PC muscle", they usually mean the deep layer, or the whole pelvic floor. The bulbospongiosus isn't part of it. Our guide to the PC muscle covers the deep layer.

How to feel it

The NHS leaflet's cue is a good place to start: "tighten your back passage as if you're trying to stop yourself passing wind".¹¹ You should feel a small grip draw up and in, between your scrotum and your anus. Keep breathing, and keep your belly and buttocks soft. Then let it go completely.

You can see the outer layer working, too. In a mirror, the base of your penis should move nearer to your abdomen and your testicles should rise.⁸ Our guide to finding your pelvic floor has three checks and a labelled diagram.

Bulbospongiosus exercises: Kegels

There's no separate exercise for the bulbospongiosus that we've found tested. A Kegel works the pelvic floor as a whole, and the mirror check above is how you know the outer layer joined in. You don't need to aim for one muscle. The cues NHS and trial instructions use are for the whole pelvic floor.^11,8

Start with Kegel exercises for men, which has the four steps, a beginner routine and seven exercises from first squeeze to advanced. The free Kegel timer counts a short session out loud.

What the research does and doesn't show

The bulbospongiosus and the ischiocavernosus are the muscles the research on erections and ejaculation looked at. Studying a muscle isn't the same as showing that training it helps.

Pelvic-floor training has been studied for erection problems. The trials were small, mostly supervised clinic programmes with biofeedback, and their results were mixed. No guideline recommends training for erection problems, so treat it as one tool alongside a check-up with your doctor.^8,9,10 Our guide to whether Kegels work for men goes through the studies.

When to stop

See a doctor before you train if

• You have new or changing urinary symptoms, like a weak stream, straining, peeing more often or at night, or new leaks. See a doctor before starting pelvic-floor training.¹²
• You have had prostate or pelvic surgery or radiotherapy. Follow your care team's plan first. GoBeast isn't designed for recovery after surgery.¹³
• There is blood in your pee. Ask for an urgent doctor's appointment.¹⁴
• You can't pee at all. Get urgent medical help today.¹²
• You have erection problems that keep happening, or no erections at all, including on waking. See a doctor. Erection problems that keep happening can be an early sign of heart or blood-vessel problems, and that matters even if you're young.^15,10

Questions