Positioning device and a patient support device and a medical imaging device with the positioning device

The invention relates to a positioning device which is designed in particular to an active support of a bearing and / or positioning a patient on a patient support device, with a slide bearing unit to a movable mounting of the positioning device on the patient support device and a support unit with at least two contact areas, wherein at least a first of the at least two support areas to a storage and / or support is adapted to the patient support apparatus and at least a second of the at least two support areas designed for a positioning aid for positioning the patient.