Orthopaedic cushion, comprising a shaped foam block which is provided with a holding cavity, being shaped in accordance with the shape of a body part, for holding the body part in order to position and support this body part, the orthopaedic cushion being provided with: - a ventilator for sucking in air and expelling this air via an outlet; - an air duct for the passage of air from the outlet of the ventilator and expelling this air via an outlet opening at the bottom of the holding cavity; - a fabric comprising a top layer, a bottom layer, and shaped spacers in between the top layer and the bottom layer, between which a space, which allows through-flow of air, is present, the fabric being fitted over the outlet opening in the holding cavity and up to lateral sides of the holding cavity for diffusing air and discharging this air via these lateral sides; characterised in that the outlet opening is provided in an aperture at the bottom of the holding cavity, and in that the orthopaedic cushion is provided with an air-distributing element which is removably provided in the aperture, for distributing air from the air duct across several outlet openings, the air-distributing element comprising: - a base which is arranged at the bottom in the aperture and forms a collecting tray for moisture in that it comprises a bottom which is delimited at the periphery of the bottom by a first upright edge and which comprises a passage opening in the bottom, wherein this passage opening is delimited by a second upright edge of the base and is connected to the outlet opening; and - an insert which is detachably arranged at the top of the base and which delimits said outlet openings; and in that the fabric is a three-dimensional fabric, which is fitted over these outlet openings in order to diffuse the air from these outlet openings. - a ventilator for sucking in air and expelling this air via an outlet; - an air duct for the passage of air from the outlet of the ventilator and expelling this air via an outlet opening at the bottom of the holding cavity; - a fabric comprising a top layer, a bottom layer, and shaped spacers in between the top layer and the bottom layer, between which a space, which allows through-flow of air, is present, the fabric being fitted over the outlet opening in the holding cavity and up to lateral sides of the holding cavity for diffusing air and discharging this air via these lateral sides; characterised in that the outlet opening is provided in an aperture at the bottom of the holding cavity, and in that the orthopaedic cushion is provided with an air-distributing element which is removably provided in the aperture, for distributing air from the air duct across several outlet openings, the air-distributing element comprising: - a base which is arranged at the bottom in the aperture and forms a collecting tray for moisture in that it comprises a bottom which is delimited at the periphery of the bottom by a first upright edge and which comprises a passage opening in the bottom, wherein this passage opening is delimited by a second upright edge of the base and is connected to the outlet opening; and - an insert which is detachably arranged at the top of the base and which delimits said outlet openings; - a base which is arranged at the bottom in the aperture and forms a collecting tray for moisture in that it comprises a bottom which is delimited at the periphery of the bottom by a first upright edge and which comprises a passage opening in the bottom, wherein this passage opening is delimited by a second upright edge of the base and is connected to the outlet opening; and - an insert which is detachably arranged at the top of the base and which delimits said outlet openings; and in that the fabric is a three-dimensional fabric, which is fitted over these outlet openings in order to diffuse the air from these outlet openings.