Cardiopulmonary complications are known in intramedullary nailing, especially of the femur. Transesophageal echocardiography now allow intraoperative detection of embolized bone-marrow, recognizable as reflecting particles in the right atrium. In intramedullary nailing of a femoral fracture with a closed distal fragment bone-marrow embolism was detectable in the right atrium during reaming of the medullary canal. This technique should permit further research on the pathophysiology of pulmonary alterations during intramedullary nailing and also testing the effectiveness of pressure-relief in the medullary canal as proposed by drilling a bone-hole.