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Absent bow tie sign (knee)

Last revised by Dr Daniel J Bell ◉ on 08 Dec 2021

Citation, DOI & article data

Citation:

Gaillard, F., Bell, D. Absent bow tie sign (knee). Reference article, Radiopaedia.org. (accessed on 18 Aug 2022) https://doi.org/10.53347/rID-7218

DOI:

https://doi.org/10.53347/rID-7218

Permalink:

https://radiopaedia.org/articles/7218

rID:

7218

Article created:

17 Sep 2009 by Assoc Prof Frank Gaillard ◉ ◈

Revisions:

19 times by 11 users - see full revision history

System:

Musculoskeletal

Section:

Signs

Tag:

knee

Synonyms:

Absent bow tie sign in knee

The absent bow tie sign represents the loss of the normal appearance of the menisci on parasagittal MRI images and is suggestive of meniscal injury.

Normally the medial and lateral menisci appear as low signal bow tie-shaped structures between the femoral condyles and tibial plateau. As the normal meniscus laterally measures 9-12 mm in width, it should be seen on a number of adjacent images (2-3 images if imaged with 3 mm thick slices with a 1 mm skip).

An absent bow tie sign is therefore when less than two sagittal slices demonstrate a normal body of the meniscus, and is indicative of meniscal pathology, including:

bucket handle tear with displacement (often with a double PCL sign)
flap tear with displacement (i.e. bucket handle, but the handle at one end has come loose)
free fragment with displacement (i.e. bucket handle, but the handle at both ends has come loose)

Other meniscal changes can, however, appear similar, including: