Fig. 6

Popliteal artery entrapment syndrome (PAES) in a 31-year-old woman admitted to the hospital because of a 6-week history of right calf pain and numbness. Patient also reported half-block claudication. (a) Lower extremity digital subtraction angiography reveals obliteration of the popliteal artery (arrow). Given the lack of risk factors for an arterial thrombus, an anatomic etiology was suspected. (b, c) Axial selective partial inversion recovery (SPIR) MR images of the right knee showing an accessory slip of the lateral head of the gastrocnemius muscle (arrow) crossing anterolateral to the popliteal vessels, with resulting compression of the popliteal artery (arrowhead). The accessory slip (arrow) joins the lateral head of the gastrocnemius distally (star). This finding supports a diagnosis of PAES