Abstract: A connection device for adjustably connecting a surgical apparatus connected to a first end of the connection device to an attachment part on a stationary device, such as an operating table, which can be connected to a second end of the connection device. The connection device has a first holding arm and a second holding arm, connected to the first holding arm in a hinged fashion via a ball and socket joint. A clamping apparatus is provided for detachably clamping the ball of the ball and socket joint in the ball and socket joint receptacle. A hydraulic apparatus is also provided which, when operated, loads the clamping apparatus with a force opposing the clamping force. Further, a clamping force transformation apparatus transforms the force applied by the clamping apparatus into a larger clamping force.