Prostate Gland Anatomy
The prostate is a small gland (about the size of a walnut) that wraps around the urethra, the tube that carries urine from the bladder to outside the body. When describing the prostate's anatomy, it is divided into both zones and lobes. Your surgeon may refer to a specific zone, a specific lobe, or both when describing your surgery or diagnosis.
Zones of the Prostate
The prostate anatomy can be divided into zones, categorized by the function of the prostate tissue. The prostate is made up of the peripheral, central, and transitional zones.
The peripheral zone is the outermost area of the prostate, resting closest to the wall of the rectum. It makes up approximately 70% of a healthy prostate gland.
The next layer is the central zone, which is approximately 25% of the prostate tissue. This area contains the ejaculatory ducts, which help move semen through the urethra and out of the body.
The transitional zone of the prostate, resting next to the urethra, makes up around 5% of the prostate at puberty. This zone continues to increase in size throughout adulthood.
Lobes of the Prostate
The anatomy of the prostate is made up of three lobes: the central lobe and lobes on either side, called the anterior lobes.
The central lobe of the prostate is pyramid shaped and rests between the ejaculatory ducts and the urethra.
The anterior lobes of the prostate rest near the urethra. This tissue is non-glandular, meaning it does not secrete fluids. It is made up of muscle and fibrous tissue.
Anatomy of the Prostate Gland. The Ohio State University Hospitals. Accessed May 2010. http://medicalcenter.osu.edu/patientcare/healthcare_services/prostate_health/anatomy_prostate_gland/pages/index.aspx