Femoral neuropathy occurs when occult retroperitoneal bleeding impinges on the appropriate nerve roots. The syndrome involves the acute onset of groin and thigh pain with characteristic flexion and external rotation of the hip. It may mimic other conditions such as acute arterial occlusion. Thorough knowledge of the anatomy of the femoral nerve explains the clinical features and leads the clinician to suspect the occurrence of this syndrome. Three cases have been reviewed that exhibited this condition as a result of retroperitoneal bleeding, a complication of systemic heparin therapy. The hemophilia that afflicted Alexis, the Crown Prince of Russia and son of Tsar Nicholas and Tsarina Alexandra, resulted in this clinical syndrome. The consequences enabled the sinister starets, Gregory Rasputin, to become intimately involved with the royal family, influencing the response of the Tsar to the political events in Russia, thereby playing an important role in setting the stage for the 1917 Russian communist revolution.