Urinary bladder
Vesica urinaria
UrinaryOrgansPelvis
- What it is
- Hollow muscular reservoir behind the pubic symphysis. Its wall is the detrusor muscle (interlacing smooth-muscle bundles) lined by stretchy urothelium that folds into rugae when empty.
- Function
- Stores urine at low pressure and empties it during micturition, when the detrusor contracts and the urethral sphincters relax.
- Size
- Capacity 400–600 mL (urge at ~150–250 mL); shown moderately full, about 8 cm across.
- Clinical note
- As it fills it rises above the pubis into the extraperitoneal space, so a full bladder can be drained by a suprapubic catheter without entering the peritoneum.