Teenager with right lower quadrant pain Transverse US of the right lower quadrant (above) shows a dilated, blind ending, non-compressible tubular structure (between the calipers) that is draped across the right psoas muscle and whose tip lies just above the right iliac vessels. Sagittal US of the right lower quadrant (below) showed the tubular structure to have a diameter of 9 mm The diagnosis was acute appendicitis.