The pelvic cavity is a more difficult area to scan and takes experience.
Probe position
The typical appearance of small bowel loops floating in fluid is a give-away, but much smaller volumes of fluid in the retrovesical pouch in the male, or the pouch of Douglas in the female, can be diagnostic. The technique for selecting these areas needs to be mastered in a practical session.
NB: A small amount of fluid in the pouch of Douglas, in the female pelvis, may be normal following ovulation.
Normal scan: pelvis in transverse view
Normal scan: pelvis
Abnormal scans
Fluid in the pelvis
The small bowel loops are clearly seen floating in the fluid.