An adapter device for detachably fastening instruments and equipment to a side rail of an operating table includes a clamping device by means of which the adapter device can be clamped to the side rail of the operating table, a longitudinal profile onto which the instruments and equipment can be detachably fastened, and a joint having at least one pivot axis formed between the clamping device and the longitudinal profile so that the longitudinal profile is pivotable relative to the clamping device about the pivot axis of the joint.
