Prostate

The shape of the prostate has been compared to an inverted, compressed cone. It lies imediately below the base of the bladder, in front of the rectum, and encircles a roughly one-inch portion of the urethra as it leaves the bladder. The ejaculatory ducts, which are formed by the convergence of each seminal vesicle and its corresponding vas deferens, perforate the prostate posteriorly and empty into the prostatic urethra. Because the urethra has both excretory and reproductive functions, it can close the bladder neck temporarily at the time of ejaculation to separate urine and semen.

The prostate undergoes significant growth during fetal development and again during puberty. At age twenty the gland has reached normal adult size, approximately the size of a plum. It remains stable in size unless malignancy or benign prostatic hyperplasia causes further enlargement.