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Dx: Evidence of Free Fluid Visible on Ultrasound
The image is of the elbow joint in approximately 90 degrees of flexion with the probe just posterior to the lateral epicondyle. The cortex of the radial head and lateral epicondyle of the humerus are somewhat hyperechoic (white) with some posterior shadowing, especially behind the lateral epicondyle. Between these two bones and within the joint, there is evidence of free ﬂuid, which appears hypoechoic (dark).
A picture is worth a thousand words when it comes to obtaining an informed consent. After seeing the difference between the normal and abnormal elbow ultrasound, your patient concedes and agrees to let you drain his septic joint. He signs the consent form; you set up for a sterile procedure, and a few minutes later the nurse is sending some cloudy looking ﬂuid to the lab for analysis. Back on track, you look for your colleague to let him now you have the “ﬁve A’s” down as well as the “U” for ultrasound.
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