The "dog leg" sign is a secondary angiographic sign on popliteal angiography, which demonstrates an irregular lumen of the popliteal artery with acute bend in the course of the popliteal artery. It is characteristically seen in popliteal artery aneurysms with mural thrombus.
It is an important sign because 26% of popliteal artery aneurysms do not show dilatation on angiography 1. The presence of this sign should prompt investigation to assess for commonly associated other aneurysms namely contralateral popliteal, femoral, iliac and/or abdominal aortic aneurysms.
Other imaging modalities can accurately differentiate between these entities.
- 1. Holdsworth RJ, Raza Z, Naidu S et-al. The radiological appearance of atherosclerotic popliteal artery aneurysms: the "dog-leg" sign. J Cardiovasc Surg (Torino). 1997;38 (2): 181-2. Pubmed citation
- 2. Uppal A. The dog leg sign. Radiology. 2000;214 (2): 339-40. doi:10.1148/radiology.214.2.r00fe26339 - Pubmed citation