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Patient information: PENIS

URO SPECIAL. Special pages for special problems. Information on frequent urological problems. Impotence - Interstitial Cystitis - Vasectomy Reversal   KIDNEY. An introduction about the location and form of the kidneys, and their function in daily human life. About what may go wrong and how to find out. And what can be done about it.   BLADDER. Where is it located and what is it for. Can it cause trouble; and if it does, what kind of trouble. Which examinations exist. Which kind of solutions are there when it does not function properly.   PROSTATE. An organ that, especially in the elderly, is quite often thought and talked about, although many do not know what it is for and/or where it can be found. How does one go about to find out whether the prostate does or does not do what it is intended to do, whether it is obstructing etc. How can problems be solved. Included is a questionnaire to get an estimate on the severity of urinating problems.   PENIS. An organ that, especially in the younger, is quite often thought and talked about, while most do know what it stands for and how it looks like. Many people, however, do not know how it (he) works and what can be done if it (he) does not work.   TESTICLE. Like the kidneys, the testicles are supplied in duplicate. They harbour two distinct functions. What can go wrong and how can we solve that. How can the testicles be tested.   UROLOGY. What kind of doctor is a urologist anyway, what does he/she do. Which part of the body 'belongs' to the 'urologic area'. Also the location of the small print. UROPANEL: questions to the urologists' panel.




PENISAlthough the penis (dick, rod, Latin: penis, hanger) is a rather ordinary, everyday organ (at least for about 50% of the population), it is surprising how little some people know about this part of the body.
In some animals, the penis is equipped with a small bone, not so in humans. In the adult male, the penis is about 2 to 3 inches long, although this can differ from day to day. When it is cold, the penis can withdraw into the fatty tissue overlying the pubic bone, which makes it seem shorter, especially in men with a lot of fat there. There is generally little variation in the 'real' length of the penis between different men; in some races it's somewhat longer, in others a bit shorter. During erection, the penile length varies between 6 and 8 inches.

Three major structures can be found in the penis: the urethra and two long cylinders, the erectile bodies.

  • The urethra, with a thick, spongy cylinder around it, is located below. The urethra is designed to conduct urine to the outside world, but can only be considered a tube when it does; after the urine is expelled, the elastic fibers in its wall make sure it collapses. The tube ends at the glans of the penis. The skin on the glans is very sensitive and is normally protected by the foreskin, which acts as a cover. The foreskin should be able to slide back and forth over the glans easily, although this is not always the case yet in children. To ease the sliding, small glands produce a kind of grease. When this area of the body is not cleaned regularly, the grease may become noticeable as smegma. In the middle of the lower part of the foreskin a small skin-slip can be found (Latin: phrenulum), running from the foreskin towards the opening of the urethra; the function of this slip of foreskin is unknown, but sometimes it can be painful during erections when it is too short.
  • The erectile bodies, long cylinders, that are located next to each other at the 'back' of the penis. They contain blood. During erection, the amount of blood inside the cylinders increases, because the inflow increases and the outflow of blood decreases; the cylinders are filled to the limit with blood and will stand upright, causing erection of the penis; it works just like those cylindric balloons. To ensure a good blood supply, several blood vessels run towards the erectile bodies and a dense web of small nerve fibers ensure the opening and closing of the right vessels during erection. Since there are no stiff structures, like bones or something similar, in the penis to give it rigidity, the penis is connected to the pubic bone by strong connective tissue; because of this, the erect penis is still rather stabile and pointing slightly upwards.



As you will undoubtedly know, the penis has three functions:

  • Urinating. This is a rather plain and simple function, where the penis serves as a extension of the urethra, thus enabling males to urinate easy anywhere they want without spilling any urine. In women this is more difficult and they will have to find a place to squat.
  • Sexuality. Simply put: an erect penis, i.e. a stiff one, can give pleasure. Having an erection is, however, a complicated procedure. In order to have an adequate erection three conditions must be fulfilled:

    1. a certain amount of lust is required (Latin: libido)
    2. a good inflow and outflow of blood is necessary
    3. the management, i.e. the nerve supply, must be functioning properly

    Getting and maintaining an erection is an automated process. It is mainly run from the nerve cells in the spinal chord. Of course, the owner of the penis does have some say in it, but only up to a limit, for instance by thinking or not thinking about someone/something (porn movies). The effects will generally be limited to erection or no erection; it is pretty hard to want to have only a bit of an erection. To show that the erection is governed by the spinal chord one can use a vibrator. The vibrations of the machine will excite the nerve endings in the glans of the penis and will elicit an erection via a reflex mechanism in the spinal chord (just like the knee-jerk reflex causes automatic contraction of the muscles in the leg). The 'erectile nerves' that run from the spinal chord to the penis will cause the inflow of blood to the erectile bodies to increase and the outflow to decrease, thus filling these bodies with blood and causing erection of the penis.
    If there is no sense of lust, the inflow of blood is too low or the nerves to the penis are damaged, then the erection will be limited or even non-existing.
  • Reproduction. In terms of evolution, erection has proven to be a good method to put male sperm into a womans womb. In ejaculation (coming) an amount of semen (prostatic fluid + sperm cells) is ejected into the urethra at the level of the prostate. The semen is propelled through the urethra by rapid muscular movements in its wall and ejected through the penis, on its way to the female egg-cell; to prevent the semen going the wrong way (to the bladder, which is closer by) the entry to the bladder is closed by a tiny sphincter at that very moment - that is the reason that ejaculation and urinating at the same time is impossible. Ejaculation is not called 'coming' for nothing: according to mother nature the goal is reached the very moment the semen came and erection is not needed any further.


Diseases, Signs and symptoms

Diseases of the penis can be subdivided into several categories:

  • Urinating.
    The urethra can become infected, which is often accompanied by an infection of the prostate (prostatitis). This causes a burning sensation while urinating and, if accompanied by an infection of the bladder (cystitis), may induce more frequent use of the toilet. Sometimes the infection is caused by a venereal disease, like gonorrhoea or a Chlamydia infection, but more often by ordinary bacteria, like common gut-bacteria.
    Another disease is a narrowing (stenosis) of the urethra, possibly the result of an earlier infection, causing difficulty in voiding and a weaker stream.
    Other voiding problems may be caused by a congenital aberration, in which the urethra does not end on the top of the penis, but before that point. This is a relatively common variation by mother nature, which does not always lead to problems; often the problem is merely an aesthetic one, which is found and surgically corrected early in life, because the parents want their son to look as normal as possible. In general, these variations do not cause many problems in adulthood, as long as the opening of the urethra is not too far from its normal location. Sometimes it can, however, cause a narrowing of the opening.
  • Phimosis.
    The foreskin is, in normal circumstances, very elastic and can be retracted easily to reveal the glans. Due to infections it can shrink to such an extend as to cause difficulty urinating. A foreskin that can not be easily retracted is too narrow (Latin: phimosis); this is often the case in young boys, but this will be corrected by itself when the child grows older, so medical attention is not needed - only when urinating is made difficult or in case of infections is therapy necessary. When retraction of the foreskin is not possible, the glans underneath can not be cleaned properly anymore and smegma will remain, causing further infections and narrowing. During erection the glans will automatically 'pop out'; if that is not possible, erection may be painful.
    At the underside of the glans a small skin-slip runs from the opening of the urethra towards the foreskin; this skin-slip is sometimes too short causing it to tear during intercourse (usually the first). Profuse bleeding is the result, followed by a nighttime visit to the emergency ward of the local hospital. Fortunately, the bleeding stops by itself and the tear lengthens the skin-slip so that it usually happens only once. In some cases, however, only a small tear results and evolving scar tissue will even shorten the slip.
    In a sense the opposite of a narrowed foreskin, which cannot be retracted over the glans anymore, is the socalled 'Spanish Collar'; In that case the foreskin is also narrowed, but its owner somehow managed to retract it over the glans, but is unable to get it back again. The foreskin will remain lodged behind the ridge of the glans, gets irritated and starts swelling, making it impossible to get it back over the ridge again. This condition is rather painful and usually requires medical attention.
  • Erection.

    1. Impotence literally means 'being unable to', so intercourse is not possible, either because of absence of erections or because erections are to weak. There was a time when it was thought that most disorders of potency were the result of psychologic problems. To an extend, this is certainly the case, but several physical disorders can also lead to impotence. Due to a narrowing of the blood vessels that supply the penis, the amount of blood flowing towards the erectile bodies during erection may be insufficient, causing lessening or even absence of erections. A 'leak' in the vessels that lead out of the erectile bodies can have the same effect. Sometimes, the nerves that have to control erections, do not function properly, are damaged, for example in patients with diabetes. Of course, psychological factors, like problems at work or in marriage, may worsen physical problems, or cause diminished potency or impotence on their own. An infection or an operation in this area of the body often leads to a temporary impotence, which is corrected once the infection or operation site is healed.
    2. Priapism. Priapos was the ancient Greek god of (male) fertility and is always depicted with a large penis, usually erected. Priapism is the medical term for a penis that will stay erect. Since this condition will lead to damage to the erectile bodies, because of the persisting high pressures inside them, this, although some might at first glance think otherwise, is not an ideal situation. In normal circumstances, the penis can stay erect up to 6 hours without too many problems, although it may cause discomfort and/or pain after a couple of hours. If erection persists beyond that period, the erectile bodies will get damaged, which could cause impotence. Priapism is usually caused by plugging of the vessels that normally take care of the outflow of blood from the erectile bodies; this may in turn be precipitated by certain diseases that cause problems in blood clotting, but may, for example, also be caused by injections in the penis by drug-addicts.
    3. A curved penis, also called Peyronie's disease. Scar tissue in one of the erectile bodies, for instance after an accident, may cause the penis to curve during erection, because the affected erectile body is somewhat less elastic than its counterpart due to the scar; the scarred erectile body is thus somewhat shorter during erection and pulls the penis into a curve. A slight curve will not be much of a problem, but some curvatures make it impossible to have intercourse. Such a scar sometimes arises out of thin air, without an accident having taken place - the cause is then unknown.

  • Peniscancer. Cancer of the penis is a rather infrequent disease. It is usually a disease of the elderly. It often starts off as a sort of wart on the glans or the foreskin. Like any cancer, it can spread to the surrounding tissues in the penis or elsewhere in the body. As a rule, the cancer grows and spreads relatively slowly. Unfortuna tely, it is often found in elderly men who also have a narrowing of the foreskin, thus masking the underlying cancer. In the beginning, the cancer is unobtrusive, but it can become painful later on. Often the first sign of cancer is a persistent infection underneath the narrowed foreskin.



There is not a large number of tests available for the penis.

  • The physical examination (the look and feel) of the penis usually gives a lot of information about it. The presence or absence of scar tissue can be determined as in penile curvature, a narrowed foreskin can be detected, but also the location and size of the opening of the urethra can be measured and possible cancer seen.
  • Blood samples are generally not useful, although sometimes the concentration of testosterone (the male sex hormone) may have its use in case of impotence, which may be related to a low testosterone level (which is seldomly the case).
  • Urine examination can be important to exclude an infection of the bladder, prostate or urethra. In a number of cases it will be necessary to use a cotton stick to 'scrape' some material (cells, bacteria) from the urethra, to be further examined in the lab. In this way, Gonorrhoea or Chlamydia infections can be checked.
  • In ultrasound of the penis, high pitched sound (which can not be heard) is used to produce an image of the penis (like SONAR in submarines). The examination is painless. Using ultrasound, it is possible to see the inner tissues of the penis, for example to determine the spread of penis cancer. A relatively new addition to the ultrasound is the use of Doppler; again by using ultrasonic waves, it is possible to get an impression of the function, or non-function, of the blood vessels. This may be important in case of impotence, where the blood supply to the penis may be insufficient.
  • Papaverine-injections in the erectile bodies of the penis can be used to analyse the possible cause(s) of impotence. If the blood supply to the penis and erectile bodies is sufficient, it is usually possible to induce an erection with such an injection. If a patient with a potency disorder shows a good erection after such an injection, this is a sign that the blood supply is sufficient (and another problem must be responsible for the loss of potency).

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It is impossible to present all possible therapeutic options for all diseases of the penis. More frequent forms of treatment will be mentioned.

  • Infections and strictures.

    1. The treatment of an infection of course depends on its cause, i.e. the type of bacteria involved. An 'ordinary' infection usually necessitates different antibiotics than a venereal disease like Gonorrhoea. Before starting therapy, one also needs to know whether only the urethra is infected or if there is a concurrent infection of the prostate, which needs to be treated as well. In some cases there might also be a stricture, a narrowing of the urethra, which, if not treated surgically, will induce a swift recurrence of the infection.
    2. The same goes for an infection of the glans of the penis, which is usually caused by a narrowing of the foreskin. In that case, treatment with antibiotics will prove to be useless. The diseased foreskin will need to be removed first (Latin: circum cisio). Since the penis is very easily anaesthetized, the circumcision is usually performed on an outpatient basis. To remove only the narrowed part of the foreskin is usually only of temporary benefit, because another stricture will quickly form at the joint of the two pieces of skin. In several religions (Jews, Islam) it is custom for the men to have their foreskin removed at a young age; usually this is done without anaesthesia and in some countries also without much knowledge of hygiene.
    3. In case of a 'Spanish Collar', in which there is also a narrow foreskin, a circumcision is the only solution. Unfortunately, it often happens that patients arrive at the doctors office rather late - some men need several days to overcome their stagefright. Most doctors have some tricks up their sleeves and are able to get the foreskin into its normal position again, but in later stages only the knife (and anesthesia) will be able to relieve the pain.
    4. Another (small) problem in need for a surgical solution is a too short skin-slip between the opening of the urethra and the foreskin. When this skin-slip really is too short, it will often tear during (the first) intercourse, thereby solving the problem ('loss of male virginity'). If this method fails, but the skin-slip remains too short, it may lead to painful intercourse. In that case, the skin-slip need to be surgically lengthened under local anaesthesia.

  • Impotence. The treatment depends on the cause of the impotence.

    1. If the problem is caused by an insufficiency of the blood flow towards the erectile bodies of the penis, it often happens that the involved blood vessels are not the only ones in the body that are insufficient. In a number of cases it is possible to reroute other blood vessels to the erectile bodies to supply them with enough blood; unfortunately, it often happens that other available vessels are also insufficient, so a bypass can not be made. In those cases, a penile prosthesis can sometimes be implanted. In that procedure, two plastic cylinders are implanted into the erectile bodies of the penis. Using a small pump, that is implanted in the scrotal sack, the cylinders can be filled with fluid, that is pumped from a reservoir put in the lower abdomen; an artificial erection is the result. Of course, this is not minor surgery and the operation should be well thought over.
    2. If an insufficient nerve supply is the cause of impotence, but the blood supply is functio ning properly, injections with papaverine or prostaglandin into the erectile bodies will often lead to near to normal erections. The patient will need to be prepared to inject his penis himself (or let his partner do it); one can not expect the urologist to do middle-of-the-night house-calls to his patients. Fortunately, this self-injection therapy is easy to learn. After the injection, the erection will usually last about 1 to 2 hours. One has to be careful not to inject too much of the solution. If the erection lasts more than 6 hours, an antidote has to be given to avoid permanent damage to the erectile bodies because of the priapism. Of course, it is important to inject properly and in a clean (sterile) way to avoid infections and damage to the erectile bodies. If improperly used, scar tissue of the erectile bodies can result, leading to penile curvatu re, although this complication is infrequent.
    3. If the impotence is caused by, or influenced by, psychological factors another course of action is needed. In these cases, a sexuologist, psychologist or social worker may be helpful. Although in these cases injection with papaverine also leads to favorable results, this is generally not a lasting, nor a justifiable solution.

  • A penile curvature ('Peyronie') may be such as to render intercourse painful or impossible. In those cases, treatment is necessary. Medication, including injections, has to date not proven to be effective, limiting treatment to surgical intervention. Usually, a cause for the curvature (like an accident) cannot be found. It may then be necessary to prevent further scarring of the cavernous bodies, before undertaking surgical correction. In order to inactivate the still forming scar tissue, low-dose radiotherapy can be used. The operation consists of creating an identical scar opposite the original one, either on the same or the other erectile body, thus pulling the penis straight again. This is done by inserting one or more non-absorbable stitches into the wall of the erectile body, while an artificial erection makes it possible to view the effect during the procedure. After the operation the penis will be a quarter of an inch shorter, but straight. The procedure can be done in day-care.
  • Penile cancer. With any type of cancer, it is necessary to act as soon as possible and try to destroy all tumor cells. Fortunately, penile cancer usually begins at the surface of the (glans of the) penis, looking like a wart, so it is often detected early. Unfortunately, it often happens that the glans is hardly visible due to a narrowed foreskin.
    If the tumor is still small and not spread to other parts of the body (like the nearby lymph nodes), a small resection (under general anaesthesia) of the tumor will often suffice; this can be done with very good cosmetic results using the Laser.
    If the tumor is too big, then often (part of) the penis has to be removed in order to be sure to remove all cancer cells. After such an operation, even a partial one, impotence is usually one of the inevitable complications, while urinating needs to be done while seated. If the disease has spread to other parts of the body, which can often be detected by X-rays (CT-scanning), the nearby lymph nodes need to be removed too. Fortunately, penile cancer can often be cured, especially when detected early.

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Last update: 22 February 2017.