the invention relates to a surgical instrument, a comprehensive housing and a drive unit which is arranged on the housing distally, a surgical tool to act on a to work on tissue, especially bone, determined or specified.the tool from the drive unit antreibbar spinning or oscillate to balance and with angetriebenem tool a drivage of the instrument relative to the tissue is possible.such a tool to provide better manageability, erfindungsgem u00e4 u00df suggested that the instrument is a vortriebermittlungseinrichtung covers, with the advance of the instrument relative to the tissue in the operation of the instrument are detectable, a send eeinheit to send at least one signala reception unit to cover the at least one signal and an evaluation unit for determining the heading using the at least one signal includes, and that at least the sendeeinheit or the reception unit to the housing or the housing is arranged.
