The prostate is a walnut-sized gland located just below the urinary bladder. Its primary function is the secretion of seminal fluid, or semen, which functions to nourish and protect sperm. Because of its location, however, it is also intimately involved in urination. In fact, prostatic diseases such as benign prostatic hypertrophy, more commonly known as BPH, often manifest as difficulties with urination. For example, those with an enlarged prostate might find that they have to strain more than they did previously to start their urinary stream. In addition, they might find that they have to get up once, twice, or even three times during the night to urinate.

In order to understand diseases of the prostate and how they affect urination the process of urination must be understood. When men attempt to urinate, they contract the urinary bladder and relax the urinary sphincter. This allows urine to pass from the bladder and out of the body through the urethra, a tube that runs from the bladder through the prostate and the penis. The prostate completely surrounds the first part of the urethra. Thus, it is a conduit through which the urine must flow before leaving the body. Also, by virtue of its location just below the bladder, the prostate is involved to a certain degree in holding urine or what one can think of as the male continence mechanism or male urinary sphincter.

BPH is the nonmalignant enlargement of the prostate gland. Prostatic growth and enlargement is a natural process that occurs in all normal men. It occurs to varying degrees; in some men growth can be excessive and can obstruct the flow of urine.

Urine flows from the bladder through the urethra as it is excreted. The first part of the urethra traverses the prostate gland and therefore, urine essentially flows through a tube that runs through the prostate. The prostate is tightly confined within the body by a capsule and cannot expand outward. Therefore, as the prostate enlarges it is forced inward, into the urethra. The result is the obstruction of the urethra and the flow of urine. In some cases, obstruction of urine flow may occur without dramatic prostatic enlargement. For other patients, significant enlargement of the prostate can be present without noticeable urinary symptoms. Although urinary problems are more common as men age and the prostate enlarges, prostate size does not directly correlate with urinary symptoms or obstruction.

BPH primarily affects men over the age of 40, of all races and ethnic backgrounds. In fact, approximately 80% of men over the age of 70 have some degree of BPH. Fortunately, not all men will suffer bothersome symptoms. Currently, it is estimated that 25%-50% of men with an enlarged prostate have some degree of bothersome urinary symptoms and require some form of medical or surgical treatment.