Organ
Urinary bladder
A compliant pelvic reservoir with coordinated emptying
High-yield
Most of the bladder is extraperitoneal, with peritoneum covering its superior and upper posterior surfaces. This distinction helps explain different patterns of traumatic urine leakage.
Overview
The bladder stores urine behind the pubic symphysis and expands upward as it fills. Its shape and position change with volume, age and surrounding organs. A compliant wall permits low-pressure storage before a coordinated neural response activates emptying.
Reference facts
- Location
- Normally anterior in the lesser pelvis behind the pubis, separated by retropubic tissue; expansion can carry it into the lower abdomen.
- Parts
- Apex, body, posterior base and neck; the apex connects to the urachal remnant and the neck continues into the urethra.
- Blood supply
- Superior vesical arteries and variable inferior vesical or vaginal branches, with other communicating internal iliac contributions.
- Innervation
- Pelvic parasympathetic pathways promote detrusor contraction; sympathetic pathways contribute to storage and outlet tone. Pudendal fibers control the external sphincter, while sensory pathways coordinate filling and voiding.
- Venous/Lymphatic drainage
- Vesical veins drain toward internal iliac channels. Lymph follows external, internal and common iliac or sacral pathways according to region.
- Relations
- Male relations include rectum and seminal vesicles posteriorly and prostate inferiorly. Female relations include uterus above/posteriorly and vagina behind the base.
- Function
- Stores urine with relatively little pressure increase and empties by detrusor contraction coordinated with outlet relaxation.
Clinical correlation
Blunt injury to a distended bladder may rupture the peritoneal-covered dome, whereas pelvic fractures commonly produce extraperitoneal injury. Mixed patterns occur. The infant bladder lies relatively higher than the adult bladder, with position still influenced by filling.
Frequently asked questions
Where is the urinary bladder located?
Normally anterior in the lesser pelvis behind the pubis, separated by retropubic tissue; expansion can carry it into the lower abdomen.
What does the urinary bladder do?
Stores urine with relatively little pressure increase and empties by detrusor contraction coordinated with outlet relaxation.
What are the parts of the urinary bladder?
Apex, body, posterior base and neck; the apex connects to the urachal remnant and the neck continues into the urethra.
What is the blood supply of the urinary bladder?
Superior vesical arteries and variable inferior vesical or vaginal branches, with other communicating internal iliac contributions.