Where is the urinary bladder located in the body?

The urinary bladder is situated in the anterior part of the lesser pelvis, posterior to the pubic symphysis. Its position varies with filling: it lies entirely within the pelvis when empty but expands into the abdominal cavity when full.

What is the trigone of the bladder and why is it important?

The trigone is a smooth, triangular region on the bladder's interior, located between the ureteric and urethral openings. Unlike the rest of the mucosa, it lacks rugae and is important for directing urine flow and preventing reflux.

How does the nerve supply control bladder function?

Bladder control involves parasympathetic nerves (S2–S4) for urination by contracting the detrusor and relaxing the internal sphincter, sympathetic nerves (T11–L2) for urine storage by relaxing the detrusor and contracting the internal sphincter, and somatic nerves (pudendal) for voluntary control of the external sphincter.

What are the main arteries that supply blood to the urinary bladder?

The primary blood supply comes from the superior and inferior vesical arteries, which are branches of the internal iliac artery. Additional supply may come from arteries like the obturator, inferior gluteal, uterine, and vaginal arteries.

What is a neurogenic bladder and what causes it?

A neurogenic bladder results from disturbed neural control of micturition. Common types include reflex (automatic) bladder from spinal cord transection above S2–S4, causing involuntary voiding, and autonomous bladder from destruction of S2–S4, leading to a flaccid bladder and overflow incontinence.

How does the bladder change shape and capacity with filling?

The bladder is tetrahedral when empty and becomes ovoid when distended. Its capacity ranges from 120–320 mL on average, with the urge to urinate starting around 250–300 mL and a maximum capacity of about 500–800 mL.

What are urachal anomalies and how do they present?

Urachal anomalies involve incomplete closure of the urachus, a fetal structure connecting the bladder to the umbilicus. They include urachal fistula, causing urine discharge from the umbilicus, and urachal cyst or sinus from partial obliteration, which can lead to infections.

What supports hold the urinary bladder in place?

The bladder is supported by true ligaments from pelvic fascia, like lateral and puboprostatic/pubovesical ligaments, and false ligaments as peritoneal folds, such as median umbilical and lateral folds.

Urinary Bladder – Anatomy, Trigone & Clinical

❓ Frequently Asked Questions