Structure
The male urinary bladder has a pyramidal shape with the base directed posteriorly and inferiorly when deflated. It is capable of great distension and is highly folded when empty. The bladder wall contains the thick detrusor muscle, which is an important barrier for malignant spread.
The apex faces the upper part of the symphysis pubis.
The superior surface is covered with peritoneum, and frequently related to the small bowel or omentum.
The inferolateral walls extend from the superior surface to meet inferiorly. They are closely related to the pubis bone of the pelvis, and the pubococcygeus muscle that arises from it.
The base is covered with peritoneum superiorly before becoming extraperitoneal on its inferior aspect. This inferior part is in close relation to the seminal vesicles and the rectum. The peritoneal fold between the rectum and bladder is the rectovesical pouch.
The most inferior part of the bladder is the neck, which is continuous with the urethra. It projects inferiorly and may be surrounded by prostatic tissue.
Relations of the Male Urinary Bladder
Superiorly, with the peritoneal cavity and the small bowel within.
Inferiorly, with the prostate gland and the periprostatic venous plexus.
Laterally, with smooth bowel (if distended) and the obturator internus muscle in the pelvis.
Posteriorly, with the rectovesical pouch and rectum (superiorly), with the seminal glands intervening more inferiorly.
Anteriorly, with the anterior abdominal wall and the pubic symphysis.
Microscopic Structure
The bladder is lined internally by urothelium (transitional epithlium). This is a special type of epithelium which is relatively flexible. Beneath the epithelium is the submucosa which contains vessels and nerves. The detrusor muscle is a thick coat of smooth muscle. The superior aspect of the bladder is covered by peritoneum; the inferior parts are coated with loose connective tissue.
