The penis contains two cylindrical, sponge like structures that run along its length, parallel to the tube that carries semen and urine (urethra). When a man becomes sexually aroused, nerve impulses cause the blood flow to the cylinders to increase about seven times the normal amount. This sudden influx of blood expands the sponge like structures and produces an erection by straightening and stiffening the penis.

Continued sexual arousal or excitation maintains the higher rate of blood flow, keeping the erection firm. After ejaculation or when the sexual excitation passes, the excess blood drains out of the spongy tissue, and the penis returns to its non-erect size and shape.

THREE STEPS TAKE PLACE TO PRODUCE AND SUSTAIN AN ERECTION: Arousal: The first step is sexual arousal, which men obtain from the senses of sight, touch, hearing and smell, and from thoughts. Nervous system response: The brain communicates the sexual excitation to the body's nervous system, which activates increased blood flow to the penis. Blood vessel response: A relaxing action occurs in the blood vessels that supply the penis, allowing more blood to flow into the shafts that produce the erection.

If something affects any of these three factors - arousal, nervous system response or circulatory system response - or the delicate balance among them, erectile dysfunction can result.

Nonphysical causes may account for impotence. The most common nonphysical causes are stress, anxiety and fatigue. Impotence is also an occasional side effect of psychological problems such as depression. Negative feelings toward your sexual partner - or expressed by your sexual partner - such as resentment, hostility or lack of interest also can be a factor in erectile dysfunction.

Still, the cause of erectile dysfunction isn't always psychological. Physical causes account for many cases of erectile dysfunction. These causes include diabetic neuropathy, cardiovascular disorders affecting the blood supply to the pelvis, prescription medications, operations for cancer of the prostate, fractures that injure the spinal cord, multiple sclerosis, hormonal disorders, and alcoholism and other forms of drug abuse. In fact, erectile dysfunction may be one of the first signs of an underlying medical problem.

The physical and nonphysical causes of erectile dysfunction commonly interact. For instance, a minor physical problem that slows sexual response may cause anxiety about attaining an erection. Then the anxiety can worsen your erectile dysfunction.

There are many underlying physical and psychological causes of erectile dysfunction. Reduced blood flow to the penis and nerve damage is the most common physical causes. Underlying conditions associated with erectile dysfunction include the following:

Vascular Diseases

Arteriosclerosis, the hardening and narrowing of the arteries, causes a reduction in blood flow throughout the body and can lead to impotence. It is associated with age and accounts for 50% to 60% of impotence in men over 60.

Risk factors for arteriosclerosis include:

• Diabetes Mellitus
• High Blood Pressure
• High Cholesterol level

Smoking, which can lead to any of the above risk factors, is perhaps the most significant risk factor for impotence related to arteriosclerosis.

Diabetes Mellitus

Chronic high levels of blood sugar associated with diabetes mellitus often damage small blood vessels and nerves throughout the body, which can impair nerve impulses and blood flow necessary for erection. About 60% of men with diabetes experience impotence.

Medications

Over 200 commonly prescribed drugs are known to cause or contribute to impotence, including drugs for high blood pressure, heart medications, antidepressants, tranquilizers, and sedatives. A number of over-the-counter medications also can lead to impotence. Long-term use of alcohol and illicit drugs may affect the vascular and nervous systems and are associated with erectile dysfunction.

Hormone Disorders

Hormone disorders account for fewer than 5% of cases of impotence. Testosterone Deficiency, which occurs rarely, can result in a loss of libido (sexual desire) and loss of erection. Among other conditions, an excess of the hormone prolactin, caused by pituitary gland tumor, reduces levels of testosterone. Hormone imbalances can also result from kidney or liver disease.

Neurologic Conditions

Spinal cord and brain injuries (e.g., paraplegia, stroke) can cause impotence when they interrupt the transfer of nerve impulses from the brain to the penis. Other nerve disorders, such as multiple sclerosis (MS), Parkinson's disease, and Alzheimer's disease, may also result in impotence.

Trauma, Surgery, Radiation

Trauma to the pelvic region or spinal cord can damage veins and nerves needed for erection. Surgery of the colon, prostate, bladder, or rectum may damage the nerves and blood vessels involved in erection. Prostate and bladder cancer surgery often require removing tissue and nerves surrounding a tumor, which increases the risk for impotence.

New nerve-sparing techniques aimed at lowering the incidence of impotence to 40% to 60% are now being developed and used in these surgeries. Temporary impotence is also associated with these procedures, even those in which nerve-sparing techniques were used. It can take as long as 6 to 18 months for full erections to return.

Radical cystectomy (for bladder cancer) and prostatectomy (for prostate cancer) require cutting or removing nerves that control penile blood flow. These nerves do not control sensation in the penis and are not responsible for orgasms; only erection is affected by these procedures.

Small or Deformed Penis is now Treatable!

New treatments are being offered by The Male Sexual Enhancement Center, a medical practice dedicated to the improvement and reconstruction of the male sexual organ. This center is affiliated with the renowned Men's Health Care Center that provides a complete range of medical services to maintain male health including prostate disease, incontinence and erectile dysfunction.

There are many congenital and acquired malformations and deformities of the male genitalia that are now treatable due to recent advances in reconstructive surgery that provide correction of soft tissue deformity and undersized penis.

What is a normal penis size?
A study published by the Journal of Urology concluded that the average flaccid penis length is about 3.5 inches and the average erect penis length is about 5 inches. A penis that falls substantially below these values is referred to as a Micropenis or Inconspicuous Penis. Although this generally does not prevent a man from being sexually active this condition may have psychological effects especially when teased by peers.

What may cause Inconspicuous Penis?
There are a number of conditions that are characterized by a penis that is small or appears to be small. (See figure 1 below). Additionally, penile retraction following a spinal cord injury is common and boys born with a condition known as Epispadius generally have penile shortening. Further study is needed to determine the natural history of these disorders and to better define beneficial treatment options.

What is penile soft tissue deformity?
There are several types of soft tissue deformity of the penis with a common one known as Peyronie's Disease. This deformity is characterized by a slow progressive bending of the penis especially during an erection and generally results in pain on erection or during sexual intercourse. Soft tissue deformities may involve the skin, subcutaneous tissue, or a combination of both.