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

eFAST — Right Upper Quadrant (Morison's Pouch)

The most sensitive view for free intraperitoneal fluid in the supine trauma patient: the hepatorenal recess.

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

  • Obtain a RUQ coronal view using the liver as an acoustic window.
  • Identify the hepatorenal recess (Morison's pouch), the subphrenic space, and the inferior pole of the kidney.
  • Recognize anechoic free fluid and the costophrenic angle for hemothorax.

Maps to

  • Resident: ACEP Emergency Ultrasound — FAST: Image Acquisition (RUQ)
  • Resident: ACEP Emergency Ultrasound — FAST: Free-fluid identification
  • Tech: ARDMS Abdomen (AB) — peritoneal free fluid

Acquisition — getting the view

Probe
curvilinear
Patient position
Supine. Trendelenburg increases sensitivity for upper-quadrant fluid.
Orientation convention
radiology
Probe placement
Right mid-axillary line, ~10th–11th intercostal space
Marker direction
Indicator cephalad (coronal plane)

Probe placement (3D)

Right mid-axillary line, ~10th–11th intercostal space

Structures in the imaging plane (near → far): Flank soft tissue · Liver · Hepatorenal recess (Morison's pouch) · Right kidney · Diaphragm

Step by step

  1. Place the curvilinear probe in the right mid-axillary line around the 10th–11th rib space, indicator toward the head.
    Why: Uses the liver as an acoustic window onto the kidney interface.
  2. Slide and angle through the entire liver–kidney interface, from diaphragm to the inferior pole of the kidney.
    Why: Free fluid can collect at the inferior pole or the subphrenic space, not just Morison's pouch itself.
  3. Angle cephalad to bring the diaphragm and costophrenic angle into view.
    Why: Screens for hemothorax above the diaphragm.

Troubleshooting

Rib shadows interrupt the image.
Rotate the probe slightly oblique to align with the intercostal space.
Bowel gas obscures the view.
Move more posterior ('knuckles toward the bed') and use the liver as the window.

Findings: normal

Normal hepatorenal interface

The liver and right kidney meet at a bright interface with no anechoic stripe between them.

Schematic of a normal hepatorenal interface
Schematic: liver–kidney interface with no free fluid.
Original schematic, dedicated to the public domain (CC0).

Findings: pathology

Free intraperitoneal fluid

An anechoic (black) stripe in Morison's pouch, at the inferior pole of the kidney, or in the subphrenic space indicates free fluid — blood in the trauma context.

Signs: Anechoic stripe in the hepatorenal recess; Spine sign above the diaphragm suggests hemothorax

Schematic of free fluid in Morison's pouch
Schematic: anechoic free fluid in the hepatorenal recess.
Original schematic, dedicated to the public domain (CC0).

Interpretation practice

An anechoic stripe appears between the liver and right kidney in a hypotensive trauma patient. What does this represent?

RUQ view with anechoic stripe at the hepatorenal interface
What is the black stripe between liver and kidney?
Original schematic, dedicated to the public domain (CC0).

Check your understanding

Why is the RUQ the highest-yield FAST view in a supine patient?

Which probe and orientation are standard for the RUQ FAST view?

References

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