Surgical instrument having a magnetically driven detachable tool assembly

A medical instrument for use on a patient. The medical instrument includes a housing having a proximal end and a distal end, an electric motor mounted to the housing having a drive shaft rotatable about a drive axis, a drive magnet fixed to the drive shaft of said motor which rotates with the drive shaft about the drive axis, and a tool assembly coupled to the housing via a tool mount. The tool mount orients the tool assembly relative to the housing whereby guided rotational, translational, and/or oscillary motion of a tool within the tool assembly is achieved via the structure of the tool mount in conjunction with a magnetic coupling between magnets attached to both the motor and the tool.