Abstract: An apparatus for displaying medial patient data has a first signal source for generating a first video signal for outputting on a display screen. The video signal contains image data for a first image foreground and a first image background, with the image foreground representing a first set of medical patient data. The apparatus also has a second image source for generating a second video signal. The second video signal represents a second set of medical patient data. A video signal superimposition unit is configured to superimpose the first and second video signals in a manner such that the image data from the first image background is overwritten with image data from the second video signal.