Abstract: An ankle stress machine particularly suited for use in the X-ray examination of ankles is disclosed. The ankle stress machine includes a planar base (11) having an aperture (12) near one end suitable for receiving a standard X-ray cassette (14). Mounted on the base (11) is a calf restraining mechanism (13). The calf restraining mechanism (13) supports the calf of a patient in a horizontal position and includes braces for preventing lateral horizontal movement in at least one direction. Mounted on the base (11) above the cassette aperture (12) is a turntable (15). Mounted atop the turntable (15) is a foot support and stress assembly (17) that includes a foot cup (93) and a radial arm (75). The foot cup (93) is vertically oriented and receives the foot of a patient. The foot cup conforms to the heel of the patient's foot, and encloses the bottom and sides of the foot between the heel and the end of the metatarsal bones of the largest foot to be accommodated.