Ultrasound Teaching Atlas
Draft — not yet peer-reviewedcoreAbdomen / Right upper quadrantBiliary

RUQ / Biliary (Gallbladder)

Evaluate the gallbladder for stones, wall thickening, and pericholecystic fluid, and measure the common bile duct.

This module is a content/teaching-structure draft. Images shown are illustrative schematics — real, de-identified, license-verified ultrasound clips replace them before peer review.

Learning objectives

  • Locate the gallbladder using the main lobar fissure ('exclamation-point' sign).
  • Image the gallbladder in both long and short axis.
  • Recognize gallstones, wall thickening, pericholecystic fluid, and a sonographic Murphy's sign.
  • Measure the common bile duct at the portal triad ('Mickey Mouse' sign).

Maps to

  • Resident: ACEP Emergency Ultrasound — Biliary: Image Acquisition
  • Resident: ACEP Emergency Ultrasound — Biliary: Cholecystitis findings
  • Tech: ARDMS Abdomen (AB) — biliary system

Acquisition — getting the view

Probe
curvilinear
Patient position
Supine; roll to left lateral decubitus and use deep inspiration if the gallbladder is hard to see.
Orientation convention
radiology
Probe placement
Right subcostal / intercostal, ~7 cm right of the xiphoid ('X-minus-7')
Marker direction
Indicator cephalad, then rotate 90° for short axis

Probe placement (3D)

Right subcostal / intercostal, ~7 cm right of the xiphoid ('X-minus-7')

Structures in the imaging plane (near → far): Abdominal wall · Liver · Main lobar fissure · Gallbladder · Portal vein / portal triad

Step by step

  1. From the xiphoid, move ~7 cm to the patient's right and place the curvilinear probe subcostally, indicator cephalad.
    Why: The 'X-minus-7' approach reliably lands on the gallbladder fossa.
  2. Confirm the gallbladder with the exclamation-point sign — the main lobar fissure pointing to the portal vein.
    Why: Avoids mistaking bowel or the IVC for the gallbladder.
  3. Sweep through the entire gallbladder in long axis, then rotate 90° for short axis. Find the CBD at the portal triad.
    Why: Stones can hide in the neck; the CBD must be measured at the triad.

Troubleshooting

Gallbladder not visible.
Roll the patient left lateral decubitus and have them take a deep breath to drop the liver and gallbladder below the ribs.
Cannot tell the CBD from the hepatic artery.
Apply color Doppler — the artery shows flow; the CBD does not.

Findings: normal

Normal gallbladder

A thin-walled, anechoic sac with no stones, an anterior wall < 3 mm, and a common bile duct < 6–7 mm.

Schematic of a normal gallbladder
Schematic: normal gallbladder, thin wall, no stones.
Original schematic, dedicated to the public domain (CC0).

Findings: pathology

Cholelithiasis / acute cholecystitis

Echogenic, gravity-dependent, mobile gallstones with posterior acoustic shadowing. Acute cholecystitis adds wall thickening > 3 mm, pericholecystic fluid, and a positive sonographic Murphy's sign.

Signs: Stone with posterior acoustic shadowing; Wall > 3 mm; Pericholecystic fluid; Sonographic Murphy's sign; WES sign (stone-packed gallbladder)

Schematic of gallstones with posterior shadowing
Schematic: gallstone with posterior acoustic shadow.
Original schematic, dedicated to the public domain (CC0).

Interpretation practice

Within the gallbladder you see an echogenic, mobile focus that casts a clean dark shadow behind it. What is it?

Echogenic focus with posterior shadowing in the gallbladder
Mobile echogenic focus with posterior shadow — interpret.
Original schematic, dedicated to the public domain (CC0).

Measurement practice

Measure the common bile duct, inner wall to inner wall, at the portal triad.

Common bile duct measurement at the portal triad
Calipers inner-to-inner across the CBD.
Original schematic, dedicated to the public domain (CC0).
mm

Check your understanding

Which sign best confirms you are imaging the gallbladder and not a vessel?

What anterior gallbladder wall thickness is considered abnormal?

References

Related modules

← All modules