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Locating the bc muscle

P.C. or B.C. ?

I have had the intention to post this little lecture for quite some time. This question gives me the opportunity to help everyone understand the difference between men and women concerning the PC (pubococcygeus) muscle and the BC (bulbocavernosus) muscle.

There are three illustrations. They are attached to this and the next two posts. The fourth post down contains the explanation of why women contract their PC muscles to strengthen their vaginal and urinary systems and men contract their BC muscles for better ejaculation and stronger erections (and to test their LOT).

Please open all three illustrations before reading the text or view this thread with the illustrations presented in the text (en español aqui).

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Second illustration.

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Third illustration.

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I guess it doesn’t really matter what you call the muscle you contract when doing Dr. Kegel’s exercise, as long as you do it correctly and consistently. However, being a stickler for accuracy, I have to point out that men contract a different muscle than women when doing Kegels and it isn’t the PC (pubococcygeus). It’s actually the BC (bulbocavernosus). This is probably the only place on the Internet where you’ll find this distinction. Most will probably find it easier to “go with the flow” and conform to years of misconception by just calling it the PC.

Why isn’t it the same muscle? Men and women are different. Females have essentially internal sex organs, males essentially external. The PC muscle is located in such a way that it is above and behind the penis and it contracts up into the pelvis. While its action on the rectum may add a little to the pull on the penis, it isn’t the main muscle being exercised when men do Kegels. Of course men can contract their PC muscle. They do it every time they have a bowel movement. Some probably contract it while doing the Kegel exercise (by involving the anal area), but it isn’t necessary to do so for a stronger penis.

First part of the anatomy lesson. Please see the “Pelvic Muscles” illustration. The PC muscle, along with the Iliococcygeus muscle (IC) make up the Levator ani muscle which serves as the “floor” of the pelvis, keeping your abdominal contents from sliding into your perineum. It also plays a roll in bowel movements. Both the PC and IC are made of two flat sheets of muscle (one on each side). The PC is attached in the front to the pubic bone. The two halves sweep along the sides of the pelvis and attach at the rear to the coccyx (tail bone). The IC attaches to the pelvic bone on the sides and at the coccyx in the rear like the PC. In a side view (not shown) the Levator ani is a funnel shape surrounding the rectum/anus. One of it’s main purposes is to pull the rectum back up into position after a bowel movement.

Note how the PC forms a “U” shape as it wraps around the rectum. The urethra and vagina in women are much more in contact with the PC than the urethra is in men. In addition to forming a sling around the rectum, the PC passes by the sides of and inserts into the vagina and urethra in women. The contractions of the muscle can be felt by a finger in the vagina. This is why Dr. Kegel advised his female patients (he was a gynecologist) to exercise the PC muscle. It helps tighten the vaginal canal, rectum, and urethra, especially in women who have had children which can stretch these pelvic structures and cause urinary incontinence and uterine prolapse. Dr. Kegel showed that exercising the PC muscle could strengthen the female perineum and help cure the physical ailments as well as improve their sex lives.*

Where is the bulbocavernosus (BC) muscle? Please see the “Perineal Muscles” illustration for the second part of the anatomy lesson. Both sexes have a pair of BC muscles. In females it surrounds the vaginal opening. Some women can independently contract the BC and the PC. Most contract both at the same time. In the male, the two halves of the BC are joined in a “herringbone” pattern surrounding the bulb of the penis (the internal base of the corpus spongiosum).

The BC muscle has two main purposes. One is to force liquid (urine or semen) out of the urethra. It does this by way of the herringbone interlacing of muscle fibers which, as they contract, milk the urethra toward the meatus (opening at the tip of the glans). It also happens to cause the penis to be pulled into the body (the LOT tug-back). This happens every time a man urinates. It also happens with much greater force, and with rhythmic contractions, when he ejaculates. The BC muscle is the main ejector of semen. This is why ejaculation improves by exercising it.

The other function is to squeeze blood into the corpus spongiosum and the glans. The bulb of the penis is a reservoir of blood. At the time of greatest arousal voluntary or reflex contractions of the BC and Ischiocavernosus muscles force blood into the corpora. The Ischiocavernosus muscles surround the crura of the penis (legs of the corpora cavernosa). With both sets of muscles contracting on the base and legs of the penis, a maximum erection is achieved.

Locating the BC. The old adage about stopping the flow of urine is valid in locating the BC muscle in men. Even though the urethra does have a sphincter (just below the prostate) to stop urine flow, contraction of the BC will “milk” the urethra and let the man know which muscle to use for Kegel’s exercise. The BC muscle can also be felt with the fingers by placing them between the scrotum and the anus. Contractions felt through the skin at this point (in the midline) are from the BC muscle. The illustration “P.C. or B.C.” shows the relationship of the PC muscle in men as it passes by the prostate and surrounds the rectum (top two images). It also shows the location of the BC muscle at the base of the penis (two lower images).

Searching the Internet for instructions on how men should do Kegels will bring a wide variety of exercise plans. Some say start with 20 at a sitting, twice a day, and work up to 100 doing them daily for six weeks. Another site suggests working up to 300 per day, holding each contraction for a few seconds, and doing that many every day “for the rest of your life.” There’s no set answer. Each man must evaluate his situation and exercise accordingly. The plan that starts out gradually, with a few quick squeezes, and work up to a hundred holding each one for a few seconds, sounds like a good one to start with. A few days a week should be enough to evaluate your situation. If you don’t notice a change in the force of your ejaculations or the strength of your erections, then more exercise of the BC, not PC, might be in order.

*Here is Kegel’s original article for those interested.

Wow most excellent work! Is there any tests of the PC muscle to see how effective it is? Like if you can hold or flutter it for x seconds it is weak, strong, or average? I guess that is more grading criteria of how strong it is or isn’t.

“You see, I don’t want to do good things, I want to do great things.” ~Alexander Joseph Luthor

I know Lewd Ferrigno personally.

I’m not aware of any tests for men. Even most women these days do Kegels on their own without being told to do them by a physician. Usually it’s symptoms of a problem, like urine leakage, that is an indicator that the exercises might help.

You could devise a test I guess. Get erect and hang a weight on a string from the end of your cock. See if you can lift it by contracting the BC (not PC) muscle. Add weight until you can no longer lift it. However, I don’t really see what that would tell you. Each guy is different. Probably the best measurement of how strong your BC is would be the character of your erections and the force of your ejaculations and if they seemed adequate to you.

Excellent post Westla, thank you for passing along this vital knowledge to us all. I do have a question about this though.
When I do kegals, I am contracting the BC muscle, and as far as I know I am also contracting my PC muscle, is there a connection between the two muscles that prevents contracting one without contracting the other? Like when you bend your pinky finger, you ring finger also bends with it. I know that it really doesn’t matter as far as PE goes, all those muscles need exercise, but I have tried many ways and cannot get one to contract without the other.


IW8 4/2003 5.5 BPEL 4.5 EG 218 lbs 4/2004 6.875 BPEL 5.0 EG 198 lbs

Next stop 7.0 BPEL !

Most of the voluntary control of the perineal region (including penis and anus) share a common nerve pathway. So there is a connection of sorts. However, with practice you can contract only the bulbocavernosus. It’s a matter of how hard you squeeze. By starting off gently, you first contract the BC. With an increase in effort, the anal sphincter is involved and then the PC. It doesn’t hurt anything to exercise them all, it’s just not necessary for better penile health.


One of the best posts ever. Very well explained. I wish I had your writing ability.


West, is the BC also the muscle one would need to concentrate on to prevent ejaculation, or since this process starts much deeper in the body does the PC also come into play?

Twatteaser: the man, the myth, and the legend in his own mind.


It’s nice to be here at Thunder’s where we CAN be sticklers for such things. I remember the looks I got the one (and only) time I tried to explain to some friends about the difference between adrenalin and non-adrenalin. They didn’t want to learn anything new; in fact, I was in the wrong for going against common knowledge.

Running a Massive Co-Front.

Bib: Thanks. Your comment means a lot to me.

Originally posted by iamaru

It's nice to be here at Thunder's where we CAN be sticklers for such things.

I’m just trying to help make this the best FREE penis enlargement site by providing information guys can use and in a way that’s more easily understood. Thanks for your comment RU.

Originally posted by RB

West, is the BC also the muscle one would need to concentrate on to prevent ejaculation, or since this process starts much deeper in the body does the PC also come into play?

Yes, since it is the muscle that is the force behind ejaculation. By squeezing it just before the urge to ejaculate starts you can (sometimes) stop the inevitable. But you have to catch it just before that point of no return. The longer you can hold it in contraction the more it will be fatigued and then if the wave of ejaculation comes anyway the force will be diminished because the muscle will be weak.

The only PE I knew how to do up until I found Thunder’s was to “bounce” my erections, and then when I got better at it, bouncing with a wet washcloth. I learned this from Doctor Ruth on a TV talk show and started doing it when I read it on a web-site about a year ago.

This way, when your having sex with a female, you can bounce her g-spot. I do it when in missionary position, getting up on my knees and leaning back. Yeah, baby!!

Sep. 2003: 7" bpel x 5" eg June 2004: 7 & 1/4" bp x 5 & 3/8" eg Jan. 2005: 7.5 x 5.5 Goal: 8x6 "I always knew pe existed but didn't know where to start, until I found Thundersplace."

WestLA, I agree, this is one of the most informative posts ever…

I was looking at your diagrams and realised with a bit of squeezing, that each of the muscles is seperately contractable.

One thing though - out of my own ignorance, I thought that the BC was the PC up until now! D’oh!

So, is a PC contraction in men the bearing down that takes place when you are trying to take a dump?

What about in women? I have a bad feeling that I taught my girlfriend to squeeze her BC, instead of PC…. woops!

Originally posted by secjay

So, is a PC contraction in men the bearing down that takes place when you are trying to take a dump?

No, it’s the muscle that pulls the lower part of the rectum (anal canal) back to its resting position after the, uh, dump.

What about in women? I have a bad feeling that I taught my girlfriend to squeeze her BC, instead of PC…. woops!

Well, it should be easy to correct that error by following Dr. Kegel’s instructions on how the exercises should be done. You can tell if she’s doing it correctly by where you feel contractions with your finger in the vagina. If they are at the vaginal opening, it’s the BC, an inch or so deeper, it’s the PC.

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