Dx: A Little Prick

Your ultrasound image demonstrates a magnified view of the head of the metacarpal bone. The cortex is of the rounded head is hyperechoic (bright white), with some posterior shadowing. About 1 millimeter nearfield of the cortex a small, slightly hyperechoic foreign body can be seen (Cactus Spine). There is also a small amount of surrounding tissue edema and a very thin fluid collection, which is less than 1mm thick at its widest point. Comparing to the normal anatomy of the opposite hand is quite useful in this case.

You give the patient the good news that you now know why his infection is back and the bad news that he will need surgery to remove the retained vegetable material. He asks you to call his orthopedist to see if he can go home and have the surgery tomorrow. He gets his wish and leaves happy with the plan.

Brady Pregerson manages a free on-line EM Ultrasound Image Library and is the editor of the Emergency Medicine Pocketbook series. For more information visit www.emresource.org

Teresa Wu is the Assistant Residency Director, and Director of Ultrasound and Simulation Based Training for the Maricopa Emergency Medicine Program in Phoenix, Arizona.

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