A connection device for an adjustable connection of a medical device, preferably a head restraint, to an accessory of a stationary device, preferably an operating table, is provided. The medical device can be connected to one end, and the stationary device can be connected with the other end of the connection device, and this connection device has at least two holding arms (10a, 10b, 10c) connected via a ball and socket joint, with the first holding arm (10a) comprising a joint socket (110a), the second holding arm (10b) a ball joint (12a) matched thereto. The ball and socket joint can be fixed in a desired angular position by a detachable clamping device. Here, the ball joint (12a) and the holding arm (10b) supporting it are inserted on a common connecting cone (25, 25c, 25d, 25e) and are clamped thereto in the axial and radial direction.
