An adapter (10) is described for connecting at least one accessory device (12) to an operating table (14), comprising a first fixing device for attaching a base body of the adapter (10) to the operating table (14) and a second fixing device for attaching the accessory device (12) to the adapter (10). The base body is formed from an X-ray transparent plate (16), said X-ray transparent plate (16) including a part lying on a support surface (15) of the operating table (14) and another part extending beyond the support surface (15) and forming a support surface extension for supporting a patient, when said X-ray transparent plate (16) is attached to the operating table (14).
