March 19, 2008 10:00 AM

Things You Didn't Know About Your Penis

(WebMD)  Here are some things you might have wondered about your penis, but were
afraid to ask.

No. 1: Your Penis Does Have a Mind of Its Own

You've probably noticed that your penis often does its own thing. You may remember times when it was completely inappropriate to have an erection; and yet you couldn't wish it away.

It's true that you have less command over your penis than body parts like your arms and legs. That's because the penis answers to a part of the nervous system that's not always under your conscious control. This is called the autonomic nervous system, which also regulates heart rate and blood pressure.

Sexual arousal usually isn't voluntary. The conscious mind is complicit in it, but a lot of sexual arousal goes on in the sympathetic nervous system. In addition, impulses from the brain during the REM phase of sleep cause erections, whether you're dreaming about sex or about a test you forgot to study for. Heavy lifting or straining to have a bowel movement can also produce an erection.

Just as the penis grows without your consent, sometimes it shrinks. "The flaccid penis varies in size considerably within a given man," says Drogo Montague, MD, a urologist at the Cleveland Clinic. Exposure to cold water or air makes your penis shrink. That's a function of the sympathetic nervous system.

Psychological stress also involves the sympathetic nervous system, and stress has the same effect as a cold shower, Montague says. When you're relaxed and feeling well, your flaccid penis looks bigger than when you're stressed out.

The penis is "kind of a barometer of the sympathetic nervous system," Montague says. So the greeting, "How's it hanging?" is more apt than you might have realized.

No. 2: Your Penis May Be a 'Grower' or a 'Show-er'

Among men, there is no consistent relationship between the size of the flaccid penis and its full erect length.

In one study of 80 men, researchers found that increases from flaccid to erect lengths ranged widely, from less than a quarter inch to 3.5 inches longer.

Whatever the clinical significance of these data may be, the locker-room significance is considerable. You can't assume that a dude with a big limp penis gets much bigger with an erection. And the guy whose penis looks tiny could surprise you with a big erection.

An analysis of more than thousand measurements taken by sex researcher Alfred Kinsey shows that shorter flaccid penises tend to gain about twice as much length as longer flaccid penises.

A penis that doesn't gain much length with an erection has become known as a "show-er," and a penis that gains a lot is said to be a "grower." These are not medical terms, and there aren't scientifically established thresholds for what's a show-er or a grower.

Kinsey's data suggest that most penises aren't extreme show-ers or growers. About 12 percent of penises gained one-third or less of their total length with an erection, and about 7 percent doubled in length when erect.

No. 3: Your Penis Is Shaped Like a Boomerang

Your penis is shaped like a boomerang. Just like you don't see all of a big oak tree above ground, you don't see the root of your penis tucked up inside your pelvis and attached to your pubic bone.

In an MRI picture, the penis looks distinctly boomerang-like, as noted by a French researcher who studied men and women having sex inside an MRI scanner.

One method of surgical "penis enlargement" is to cut the ligament that holds the root of the penis up inside the pelvis. This operation may give some men a little extra length if more of the penis protrudes from the body, but there are side effects. This ligament, called the suspensory ligament, makes an erection sturdy. With that ligament cut, the erect penis loses its upward angle and it wobbles at the base. The lack of sturdiness can lead to injury.

No. 4: You Can Break Your Penis

There is no "penis bone," but you can break your penis all the same. It's called penile fracture, and it's not a subtle injury. When it happens, there's "an audible pop or snap," Montague says. Then the penis turns black and blue. And there's terrible pain.

Penile fracture is rare, and it typically happens to younger men because their erections tend to be quite rigid.

Here's how to avoid penile fracture: don't use your penis too roughly. A common way that penile fracture happens, Montague says, is when a man is thrusting too hard and fast during sex, and slams into his partner's pubic bone. Also, a woman who moves wildly while on top of a man during sex can break a man's penis.

Peyronie's syndrome is a related condition that tends to show up more in older men, Montague says. An older man's erection may not be as rigid, but still is hard enough for sex. Over time, if the penis bends too much a certain way during sex, small tears in the tissue can form scars, and the accumulated scar tissue gives the penis an abnormally curved shape.

Not all penis curvature is a problem, however. "There is a lot of variability in what normal is," Cummings says.

No. 5: Most Penises in the World Are Uncut

A report by the World Health Organization (WHO) and the Joint United Nations Programme on HIV /AIDS (UNAIDS) estimates that worldwide only 30 percent of males aged 15 and up are circumcised.

Rates vary greatly depending upon religion and nationality. Almost all Jewish and Muslim males in the world have circumcised penises, and together they account for about 70 percent of all circumcised males globally.

The United States has the highest proportion of males circumcised for non-religious reasons. A whopping 75 percent of non-Jewish, non-Muslim American men are circumcised. Compare that to Canada, where only 30% are. In the U.K. it's 20 percent; in Australia it's merely 6 percent.

The practice of circumcising baby boys for medical and cosmetic reasons has become controversial in the U.S. But recently the World Health Organization (WHO) and the UUNAIDS recommended circumcision for adult men, based upon evidence that men with circumcised penises have a lower risk of being infected with HIV.

The CDC estimates that about 65 percent of all newborn boys get circumcised in the U.S.

By Martin Downs
Reviewed by Louise Chang
©2008 WebMD, Inc. All rights reserved

© 2008 WebMD, LLC.. All Rights Reserved.
Add a Comment See all 175 Comments
by MIO42 January 12, 2012 12:55 PM EST
Never let the little Head tell the big Head what to do !
Reply to this comment
by tleeuw January 4, 2012 7:56 PM EST
Thank you, tleeuw. This article is so old, and the part on circumcision was clearly copied by CBS with zero thought. Like the six african nations where AIDS rates are higher among the circumcised. And the very first study truly detailing the unnecessary loss of tissue, and its impact on sensation only just came out in 2009. It's really tough to realize US doctors aren't going to steer you to the right decision on this important matter.
Reply to this comment
by tleeuw January 4, 2012 7:51 PM EST
WebMD MUST reverse its support of circumcision and CBS needs to pull down this article that blindly parrots non-credible studies. Some doctors make a lot of money on it by generating arguments that it prevents disease. Ever notice that AIDS first spread in the USA where there was 100 percent circumcision?? Where's the prevention there?! It never helped slow VD transmission either. But mask the facts with millions of dollars of free procedures in Africa, and who needs ethics?
Then they hide the fact that it removes 90 percent of the most erogenous tissue, resulting in at least a 50% reduction in sexual pleasure.
If you didn't already know, we have it in the USA because John Kellogg the inventor of instant breakfast cereal wanted to stamp out masturbation, then thought to be not only a sin, but a cause for madness.
http://etext.lib.virginia.edu/etcbin/toccer-new2?id=KelPlai.sgm&images=images/modeng&data=/texts/english/modeng/parsed&tag=public&part=11&division=div1
It's distressing that CBS takes as a fact the findings from three STUDY, paid for and backed by Bill Gates and CDC -- the 2007 Uganda study, which was set up to get desired results --
Somehow three studies trump the conclusions of the world's MEDICAL SOCIETIES in UK, Netherlands, Australia, Canada; Even medical societies of Israel and the US never backed the correlation. The USA promotion of male genital cutting in Africa -- when medicines, condoms, partner selection, education are the real solutions -- is shameful.
CBS and CDC's trumped up numbers are used to persuade Americans to do it to healthy babies, thereby depriving them of a complete sex life.
The problems with the Africa studies is they don't prove the cause, they find a correlation. They associate circ to lower rates. But the study was not double blind (of course it couldn't be); The correlation was probably actually because the subjects couldn't have sex while the immense cut healed. They perhaps were pre-disposed not to have a sexual lifestyle if they were willing to get cut; etc.etc.
The US is the country with the most entrepreneurial medical system, and this system won't check itself from continuing a bronze-age initiation ritual and sexual repressive practice ... all because money, and of course the population has no idea what they're missing.
Hope you realize this removes half the skin, the most sensitive part and is not practiced in Europe, Russia, South America, China Japan, Canada, That's roughly the whole world except middle east and USA. Reason: medically unnecessary and a senseless waste of erogenous tissue.
This is the most harmful bunk and You by propagating it are endangering newborn American males.
Reply to this comment
by knewster January 25, 2012 8:39 PM EST
"Ever notice that AIDS first spread in the USA where there was 100 percent circumcision??"

Ever notice penile cancer in CIRCUMSIZED men is very RARE in the USA?
Circumsized is why!
by tleeuw January 26, 2012 3:01 PM EST
Well Knewster, yes, the evidence on penile cancer -- a disease that NEVER TURNS UP, and IS NOT LIFE THREATENING -- is stronger in terms of prevention, than AIDS certainly. Of course remove half of something, you know, and maybe diseases on that part may go down, maybe by ... half?
by mecanik-2009 December 27, 2011 8:00 PM EST
Now I know more then I ever wanted to know about it.
Reply to this comment
by Transatlantique December 22, 2011 10:51 PM EST
I'm sorry, but you are DEAD WRONG ABOUT "CIRCUMCISION," as it is euphemistically termed.
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-"The practice of circumcising baby boys for medical and cosmetic reasons has become controversial in the U.S. But recently the World Health Organization (WHO) and the UUNAIDS recommended circumcision for adult men, based upon evidence that men with circumcised ******* have a lower risk of being infected with HIV.

-The CDC estimates that about 65 percent of all newborn boys get circumcised in the U.S."
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It is controversial for a reason. The WHO recommendations are fraudulent because the "studies" that prompted them were only conducted in impoverished Africa where there are questionable sex practices, and not in continental Europe, where virtually no one is mutilated. Even Jews in Scandinavia are 60% intact. Even if the WHO recommendations were true, this would not prevent women from contracting it from bisexual men. A condom is far more effective in preventions, and it preserves the 25 thousand nerve endings that are robbed from men daily as babies.

Last year 63 percent of boys in America were NOT "circumcised," and quite contrary to your so called statistics. This is because intelligent parents are learning that being intact is just fine, and that most of the so called benefits are only to benefit the "doctor's" bank account.

Two hundred boys die each year from "circumcisions," and just who do we need to see about that? Eighty five percent, not 70, are intact and living proof that "circumcision" is a lie. It is a man's right to his own body to remain intact and anyone who denies this baby-to-be-a-man his right is a hypocrite, a child abuser, and a man hater. SHAME ON YOU CBS FOR GETTING YOUR FACTS WONG!
Reply to this comment
by TexFandango January 26, 2012 8:12 PM EST
I suggest you try a decaffeinated coffee.
by Overruled1 September 20, 2011 10:50 PM EDT
So, it's true, you do have 2 heads
Reply to this comment
by Overruled1 September 20, 2011 10:49 PM EDT
I still have questions, like in space how does the **** behave?
Does weightlessness contribute to fatigue?
If a boner is achieved in space, does it get flaccid or stiffer?
I'm just curious, since I cant afford space travel, I can dream though...lol
Reply to this comment
by ddog88 September 10, 2011 12:16 PM EDT
"Honey-I didn't cheat on you, it was Dick, you know where his mind is at".
Reply to this comment
by lorne46 August 9, 2011 7:34 PM EDT
Well, hello down there. How ya' hangin?
Reply to this comment
by pwgrant December 29, 2011 1:30 PM EST
The most intelligent post on any news site today.
by JUNKIENOT July 19, 2011 3:05 PM EDT
Oh i never knew that, i thought it was just to pee out of..Thanks
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