An experimental study of hematoma formation after arterial and venous puncture

Hematoma formation following the puncture of femoral veins or arteries of dogs was determined using mercury-filled strain gauges. Arterial bleeding always produced a hematoma. The duration of the swelling was prolonged if heparin was previously administered. Bleeding from the femoral vein did not produce a hematoma unless venous pressure was elevated by venous occlusion. The results indicate that the rapidly developing hematoma occasionally seen in dental practice following the administration of local anesthetics is of arterial origin.