A support assembly (10) optionally for supporting a patient during an operation or surgical procedure having an upper platform (11)； a base structure (13)； and a height adjustment mechanism which includes a pair of legs (14, 15) wherein each leg (14, 15) is located at opposed ends of the upper platform (11) and is pivotally attached thereto and is also pivotally attached to the base structure (13) and a pair of control links (40, 41) wherein each control link (40, 41) is pivotally attached to an adjacent leg (14, 15) intermediate its height and also pivotally attached to the base structure (13) characterised in that a lower end of each leg (14, 15) is movably mounted in an associated guide track (50, 51) or guide tracks (50, 51) located on the base structure (13).
