ABSTRACT
The human prostate gland has been described to consist of three anatomically distinct zones [1,2], the transitional zone, the central zone, and the peripheral zone (Figure 17.1). From the bladder, the prostatic urethra courses through the transitional zone of the prostate forming the verumontanum (seminal colliculus) and receives the paired ejaculatory ducts. Adjacent to the point of entry of the ejaculatory ducts into the verumontanum is present the prostatic utricle, which represents an embryological remnant of Mullerian duct. The urethra then exits the prostate coursing through the penis. The transitional zone of the prostate comprises as little as 5% of the total glandular tissue, although it is the location for the development of virtually all benign prostatic hyperplasia (BPH) pathologies and up to 20% of prostate cancers [1,2]. The somewhat larger central zone of the prostate, consisting of approximately 20% of total glandular tissue, lies adjacent to the urethra and transitional zone, and contains the paired ejaculatory ducts as they course from the ductus (vas) deferens. Less than 10% of adenocarcinomas may arise within the central zone of the prostate. The peripheral zone accounts for approximately 75% of the total glandular mass of the prostate. It surrounds both the transitional and central zones, and is bounded on one surface by the anterior fibromuscular stroma. The peripheral zone of the prostate is the location for the development of the majority
“1167_C017” — — #2
of adenocarcinomas. The posterior peripheral zone is accessible by digital rectal examination for palpation of nodular masses that may arise in the prostate.
