An ultrasonic surgical tool comprises a substantially planar blade body having a pair of opposed lateral surfaces and a cutting edge. A shank integral on a distal side with the blade body is provided at a proximal side with a connector for operatively linking the blade to a source of ultrasonic mechanical vibrations. The blade body is provided in at least one of the lateral surfaces with a shallow recess which is nearly coextensive with that lateral surface. The blade body has a raised rim surrounding and defining the recess, the rim being narrow on the three sides between the recess and the cutting edge.