The prostate gland has an average volume of 25 mL. It is approximately 3.5 cm long, 4.0 cm wide and 2.5 cm deep from posterior to anterior – about the same size as a walnut (Tortora and Derrickson [162]).

The prostate is an extraperitoneal structure, lying anterior to the rectum and sitting around the neck of the bladder encircling the urethra. It comprises three distinct areas/zones: the central, peripheral and the transition zones, which conform to a cone or inverted pyramid. The base of the prostate lies against the bladder and the apex on the urogenital diaphragm, which is a fibrous supporting ring that also contains the urethra. The gland is surrounded by the prostate capsule and beyond that smooth muscle and connective tissue. Between the prostate gland and the rectum lies Denonvilliers’ fascia – a peritoneal plane or space (Turner and Pati [163], Turner et al. [164]) (Figure 20.7).