- Urinary bladder: muscular reservoir of urine in the anterior pelvis, emptied via the urethra.
Location, Shape and Capacity
- Location: lesser pelvis, behind the pubic symphysis; in front of rectum (male) or uterus (female).
location of the urinary bladder in the male pelvis, with peritoneal reflection Location of the urinary bladder in the male pelvis, with peritoneal reflection.
- Shape: tetrahedral when empty, ovoid when distended.
- Position varies with volume: empty, it lies entirely within the lesser pelvis; distended, it expands upward and forward into the abdominal cavity.
- In children the bladder is abdominopelvic even when empty, as the neck lies at the pubic symphysis's upper border; it enters the pelvis by age 6 years, becoming fully pelvic only after puberty.
- Capacity: 120 to 320 ml, mean 220 ml.
- Desire to micturate arises beyond 220 ml; usually emptied at 250 to 300 ml; filling to 500 ml is tolerated with pain; beyond 800 ml, micturition passes beyond voluntary control.