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Fun with Free Fluid

3/12/13 - Thank you Dr. Katie Seal - on the advanced ultrasound rotation - for putting the following teaching points together! 

This week’s IOW comes to us from Dr’s Hudak, Dudley, Schrager and rotating med students Ira and Doris. Their images demonstrate free fluid in the pelvis and abdomen in a patient with ascites.  

The first image is a good example of free fluid in Morrison’s pouch (between the liver and right kidney). Notice the dark ("anechoic") stripe between the kidney and liver. When a patient is in the supine position the most dependant area in the upper peritoneum is Morison's pouch and the most dependant area in the lower peritoneum is posterior to the bladder in the male and the pouch of Douglas (posterior to the uterus) in the female. Placing a patient in the Trendelenburg position improves the sensitivity for detecting free fluid in the Morison's pouch view. 

Image 1

image 1

The second image s a sagittal slice thru the female pelvis. Note the free fluid surrounding the uterus and into the Pouch of Douglas. 

Image 2

image 2

In the transverse plane (Image 3), note the general appearance of the anatomy and fluid filled structures. 

Image 3

image 3

This transverse image is a great example of the “TIE fighter sign”. The free fluid completely surrounds the uterus and it appears to be floating in a sea of black fluid (urine in the bladder and free fluid in the Pouch of Douglas) bladder. For those who need a little more Star Wars background...TIE fighters are fictional starfighters in the Star Wars universe. See image for reference. In the US image, he “ball cockpit” is represented by the uterus and the “hexagonal wings” are attached by the uterine ligaments. 

Tie Fighter


John Lemos, MD, MPH
Clinical Instructor
Department of Emergency Medicine
Emory University