Gallstones and cholecystitis on ultrasound

The gallbladder sits under the liver just below the right costal margin. Ultrasound is the first-line test for gallstones and acute cholecystitis.

Live simulator — try itFull interactive lesson →

Finding it

Curvilinear probe, subcostal on the right, beam aimed up under the ribs. Ask the patient to breathe in and hold to bring the liver and gallbladder down. Rotate until the black pear-shaped gallbladder is longest, then fan through all of it.

Stone vs polyp

A stone is bright, sits in the dependent part, casts a clean acoustic shadow and moves when the patient rolls. A polyp is fixed to the wall and does not shadow.

Acute cholecystitis

Stones (especially impacted in the neck) plus wall thickening > 3 mm, pericholecystic fluid and a sonographic Murphy’s sign. Wall thickening alone is non-specific — meals, liver disease and heart failure thicken it too.

Real scans

Gallstone with acoustic shadow — A bright stone in the gallbladder casts a black acoustic shadow straight down behind it. — **Gallstone with acoustic shadow.** A bright stone in the gallbladder casts a black acoustic shadow straight down behind it. Nevit Dilmen · CC BY-SA 3.0 · source

Acute cholecystitis: thick gallbladder wall — Thickened, layered gallbladder wall in a patient with acute abdominal pain; the uploader also reports gallstones and pericholecystic fluid. — **Acute cholecystitis: thick gallbladder wall.** Thickened, layered gallbladder wall in a patient with acute abdominal pain; the uploader also reports gallstones and pericholecystic fluid. Mikael Häggström, M.D. · CC0 · source

Gallbladder polyp — A small echogenic polyp sticks to the gallbladder wall (red arrow). Unlike a stone, it does not move or cast a shadow. — **Gallbladder polyp.** A small echogenic polyp sticks to the gallbladder wall (red arrow). Unlike a stone, it does not move or cast a shadow. James Heilman, MD · CC BY-SA 4.0 · source

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FAQ

Why do gallstones cast a shadow?

They reflect and absorb almost all of the sound, so nothing returns from behind them.

What is the sonographic Murphy’s sign?

Maximal tenderness when pressing the probe directly over the gallbladder.

Related guides

Ultrasound artifacts, explainedAcoustic shadowing, posterior enhancement, reverberation (A-lines), B-lines, mirror image and edge artifacts — why they happen and how they help diagnosis.
Knobology: the four knobs that matterHow to set ultrasound gain, depth, focus and frequency — with a live simulator so you can turn the knobs and see what happens.
Morison’s pouch on ultrasoundWhat Morison’s pouch (the hepatorenal space) looks like on ultrasound, how to find it, and how to recognise free fluid — with an interactive simulator.

Educational content for learners; follow local protocols and supervision. Simulated images are generated by Sonoduck’s physics model; real images are credited individually.