The authors bring back the observation of a 48-year-old woman having induced a big painful left calf. The dread os a thrombophlebitis drew away the strarting of an anticoagulative treatment. This treatment was later supended in front of the putting in an a bvious place in echo-Doppler of a haematoma of the calf linked to a normal side of venous fluxes. This table made recall a syndrome of "coup de fouet". It is about a desease characterised by the unpromted rupture of a deep vein of the calf accomplishing a haematoma. It happens in repose or in step as at our patient. It posed a problem of differential diagnosis with a thrombophlebitis of lower limb. Evolution was favourable under treatment linking pause, an anti inflammatory and the haematoma paracentesis under echographique guidance .