Anatomy of the Prostate

Prostate Anatomy

Objectives

  • Identify and describe surface, relational, and internal prostate anatomy on sonographic images, including the four prostatic zones.
  • Identify adjacent anatomical structures of the prostate gland.
  • Recognize whether sonographic images are transabdominal or transrectal.

Prostate Gland Anatomy

  • Location:
    • Retroperitoneal
    • Anterior to the rectum
    • Inferior to the urinary bladder
    • Surrounds the neck of the bladder and urethra
  • Structure:
    • Base: Adjacent to the neck of the bladder (base of pyramid)
    • Apex: Adjacent to the urogenital diaphragm

Anatomical Relationships

  • Adjacent Structures:
    • Urinary bladder
    • Rectum
    • Seminal vesicles (paired accessory glands that produce fructose and an enzyme for seminal fluid, located lateral to each vas deferens on the postero-inferior surface of the bladder and superior to the prostate)
    • Vas deferens
    • Ejaculatory ducts
    • Urethra (Penile urethra)
    • Pubic bone
    • Epididymis
    • Testis
    • Scrotum
    • Anal canal
    • Vertebral column

Prostate Volume

  • Normal Volume: 20 – 30 ml (cm3^3)
  • Calculation: L x H x W x 0.5233
  • Enlarged Prostate: > 30 ml
  • Measurement Method: Ultrasound, with measurements taken at right angles to each other for accuracy.

Ultrasound Approaches

  • TA (Transabdominal) approach
  • TR (Transrectal) approach

Seminal Vesicles

  • Paired accessory glands
  • Produce fructose and an enzyme for seminal fluid.
  • Lateral to each vas deferens on the postero-inferior surface of the bladder.
  • Superior to the prostate.

Prostatic Zones

  • Anterior Zone (non-glandular)
  • Peripheral Zone
  • Central Zone
  • Transitional Zone
  • Urethra
  • Ejaculatory duct
  • Area of seminal colliculus
  • External urethral sphincter
  • Penile urethra
  • Ampulla of ductus deferens