Absent bow tie sign – a sagittal MRI knee sign of a displaced meniscal tear (often bucket handle type). Normally the second (or even third) image through a meniscus ressembles the appearance of a bow tie with the central portion thinning out towards the inner free edge (left image, third slice of meniscus). When a bow tie is not seen on the second image then the absent bow tie sign is positive (right image) and a search for a displaced meniscus should ensue – by looking for a fragment-in-notch sign or double PCL sign.
from our tumblr blog
http://radiologysigns.tumblr.com/
