Abdominal aortic aneurysm on ultrasound

Older patient, back or abdominal pain, low blood pressure: look at the aorta. A ruptured AAA can mimic renal colic, and bedside ultrasound finds the aneurysm in about a minute.

Live simulator — try itFull interactive lesson →

How to scan

Curvilinear probe, transverse, midline from the xiphoid to the umbilicus. Find the vertebral body (a bright arch with a shadow); the aorta sits on top of it, slightly to the patient’s left, with the IVC on the right. Use steady pressure to push bowel gas aside, then rotate to longitudinal.

Measure correctly

Measure outer wall to outer wall, anterior–posterior, perpendicular to the vessel. ≥ 3 cm is an aneurysm. Include mural thrombus — measuring only the black lumen undercalls the size.

If you can’t see it

Say “not visualised”, not “normal”. Try other angles or CT.

Real scans

Abdominal aortic aneurysm with mural thrombus (axial) — Cross-section of an aortic aneurysm. Grey thrombus lines the wall and the black flowing lumen is smaller than the vessel. — **Abdominal aortic aneurysm with mural thrombus (axial).** Cross-section of an aortic aneurysm. Grey thrombus lines the wall and the black flowing lumen is smaller than the vessel. Mikael Häggström, M.D. · CC0 · source

Abdominal aortic aneurysm (sagittal) — A markedly widened abdominal aorta (aneurysm) seen along its length. — **Abdominal aortic aneurysm (sagittal).** A markedly widened abdominal aorta (aneurysm) seen along its length. Mikael Häggström, M.D. · CC0 · source

Learn this with your hands. Sonoduck gives you a 3D patient, a probe and a coach that tells you what to do. Free to start, no signup.

Scan your first patient

FAQ

What size is an abdominal aortic aneurysm?

An infrarenal aortic diameter of 3 cm or more.

Can ultrasound see the rupture?

Often not — retroperitoneal bleeding is hard to see. An AAA in an unstable patient is treated as a rupture.

Related guides

The IVC on bedside ultrasoundHow to scan the inferior vena cava, what IVC size and respiratory collapse suggest about right atrial pressure, and the big caveats.
Hydronephrosis on ultrasoundWhat hydronephrosis looks like on ultrasound, how it differs from renal cysts, and how to use the bladder to find the cause. Live simulator and real images.
Linear, curvilinear or phased array?The three ultrasound probes explained — frequencies, footprints, image shapes and which to use for vessels, lungs, abdomen and heart — plus the probe marker convention.

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