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. 2025 Aug 28.
doi: 10.1007/s00256-025-05022-0. Online ahead of print.

Snapping low-lying articularis genu muscle belly: a rare and unexpected cause of superolateral knee pain and knee snapping

Fionn Coughlan  1   2   3 , Elise Chua  4   5   6 , Alexander Haenel  4   5 , Anne Drury  4   5 , Timothy Eanna Murray  4   5 , Mark Cresswell  4   5
Affiliations

Snapping low-lying articularis genu muscle belly: a rare and unexpected cause of superolateral knee pain and knee snapping

Fionn Coughlan et al. Skeletal Radiol. .

Abstract

We report a rare case of a low-lying anomalous muscle belly, the articularis genu muscle, as a cause of snapping and pain. The initial MR examination was reported as normal. Dynamic ultrasound evaluation allowed identification of the low-lying muscle as the etiology of the snapping and pain. Ultrasound-guided anesthetic injection confirmed the diagnosis with relief of symptoms and allowed subsequent further treatment with botulinum toxin. To our knowledge, the articularis genu muscle has not been previously described as a cause of knee snapping.

Keywords: Articularis genu; Dynamic ultrasound; Knee pain; Low-lying muscle belly; Magnetic resonance imaging; Snapping.

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Conflict of interest statement

Declarations. Ethics approval: Ethics approval was from the University of British Columbia. All images have been de-identified. Conflict of interest: The authors declare no competing interests.

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