(EN) An apparatus comprises a number of separate pulse oximetry sensors 6, 8, 10 respectively measuring pulsatile signals at different locations within the peripheral tissue of a body part. A further sensor (30, figure 2) associated with each pulse oximetry sensor may be provided to determine if a body part overlies the pulse oximetry sensor. The apparatus is used to assess the level of tissue oxygenation in the body and so can detect localised abnormalities in peripheral blood oxygenation levels, indicative of existing or potential tissue damage. The apparatus may be incorporated into a prosthetic limb 2 and also may be used to control a variable pressure mattress (22, figure 2) or cushion, compression devices (e.g. to prevent DVT), and reconfigurable articles of furniture.
