Medical device for leg support

A medical device for patient's foot support comprising a calf support coupled to a foot support and a ball joint connecting the calf support and the foot support, wherein the ball joint provides three rotational degrees of freedom and comprises a pin of the ball joint, a ball part of the ball joint and a housing, and wherein the ball part of the ball joint is arranged in the housing, the medical device further comprising a control member, a pressing element and a pre-biased spring, wherein the pre-biased spring is arranged between the pressing element and a fixed part of the calf support, and wherein, at an end distant from the ball part of the ball joint, the pre-biased spring abuts the fixed part of the calf support, and at an end near to the ball part of the ball joint, the pre-biased spring abuts the movable pressing element, which is coupled with the control member, wherein the pre-biased spring is operable to exert force on the pressing element to move the pressing element to press against an outer surface of the ball part and exert pressure on the ball part to releasably fix the calf support in a set position.