Clinical exam · Kidney, genitourinary, breast and obstetric exam

Bladder examination: the distended bladder !

Exam technique

A full bladder that cannot empty forms a round lump above the pubic bone. It can be seen, felt, and sounds dull when tapped.

Updated 2026-11-01

See it in 3D: Urinary bladder · Pubic symphysis · Prostate

What it is

The empty bladder lies hidden behind the pubic bone and cannot be felt. When it fills and does not empty (urinary retention), it rises toward the umbilicus as a distended bladder: a midline, rounded, tense mass that is dull to percussion and brings on the urge to void when pressed. Recognising it stops a retention from being mistaken for oliguria, and checking for it is a daily nursing task after surgery, in older adults and in patients on opioids.

Landmark anatomy

The empty bladder is pelvic, behind the pubic symphysis; as it fills it rises above the pubis toward the umbilicus, against the front abdominal wall.
Bladder dullness is central with an upper border convex upward; the flanks stay tympanic.
In women the uterus lies just behind the bladder: a pregnant uterus or a fibroid can mimic a distended bladder.

Technique, step by step

Explain the exam, ask permission and ensure privacy; ask when the patient last passed urine and whether the bladder feels full.
Patient supine with the lower abdomen exposed; look for a rounded midline bulge above the pubic bone.
Palpate from the umbilicus down toward the pubis with a flat hand, feeling for the upper edge of a smooth, tense, rounded mass.
Percuss in the midline from the umbilicus downward: the change from tympany to dullness marks the bladder's upper border, convex upward.
Press gently over the mass and ask whether the urge to void increases or whether it hurts.
If in doubt, measure the volume with a portable bladder ultrasound or measure the post-void residual, following local protocol.
Record the time, findings and volume, and report the retention to the care team.

Abnormal findings

Painful distended bladder and inability to void: acute urinary retention, often from prostatic hyperplasia, anticholinergic medicines or opioids, anaesthesia, or severe constipation in older adults.
Painless distended bladder with constant dribbling: chronic retention with overflow incontinence, common in neurogenic bladder (diabetes, spinal cord injury).
In older adults, retention may present only as agitation or delirium.
'Oliguria' with a distended bladder is not renal oliguria: it is a low obstruction that resolves when the bladder is emptied.

Common errors

Confusing a distended bladder with ascites: ascites gives flank dullness and central tympany; the bladder gives the opposite.
Not thinking of the bladder in a restless post-operative patient or one with 'oliguria'.
In women, forgetting pregnancy or a fibroid as a cause of a suprapubic mass.
Percussing from the pubis upward and missing the change in note; percuss from the tympanic umbilicus down toward the pubis.

Test yourself

Think of the answer, then tap the question to see it.

What does the dullness of a distended bladder look like on percussion?

Central and suprapubic, with an upper border convex upward and tympanic flanks.

What should be looked for first in a post-operative patient with little urine and lower abdominal discomfort?

A distended bladder from urinary retention, before blaming the kidney for the oliguria.

What is overflow incontinence?

The constant leak of small amounts of urine from a chronically full bladder that cannot empty.

How does percussion separate a distended bladder from ascites?

In ascites the flanks are dull and the centre tympanic; in a distended bladder the dullness is central and the flanks tympanic.

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See it in 3D

The structures of Durgical's 3D anatomy where it is found.

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Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: Urinary Retention - NIDDK (National Institute of Diabetes and Digestive and Kidney Diseases, 2024); Urge incontinence: MedlinePlus Medical Encyclopedia (MedlinePlus (U.S. National Library of Medicine), 2024); Urine output - decreased (MedlinePlus (U.S. National Library of Medicine), 2024).

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Representative model, for educational purposes only.