Artefacts
Comet tail artefact
This is a type of reverberation artifact. It results in a short train of reverberations from an echogenic focus which has strong parallel reflectors within it .The comet tail artifact is a grey scale ultrasound finding seen in small calcific, crystalline or other highly reflective objects.
Study the first image to recognize the different layers. If you are sure about the layers, swipe to the second image to view the answer (if applicable).