A spacer for separating bones of a joint, the spacer comprising: a frame having a longitudinal axis, and having at least one ramped surface; a first endplate configured to engage a first bone of the joint, and having at least one ramped surface mateable with the at least one ramped surface of the frame, whereby when the first endplate is moved relative to the frame in a direction along the frame longitudinal axis, at least one end of the first endplate is moved in a direction away from the frame to open the spacer; a second endplate configured to engage a second bone of the joint; a link moveable with respect to the frame, the link having a projection pivotally engageable with the first endplate to thereby move the first endplate along the frame longitudinal axis when the link is moved with respect to the frame; and an actuating screw (110A-E) moveable with respect to the frame and connected to the link to cause movement of the link when the actuating screw (110A-E) is moved with respect to the frame, characterized in that the spacer is moveable from a collapsed position to an open position, wherein a distance between a distal end of the first endplate and a distal end of the second endplate in the open position is greater than the distance between the distal end of the first endplate and the distal end of the second endplate in the collapsed position and wherein a distance between a proximal end of the first endplate and a proximal end of the second endplate in the open position is less than or equal to the distance between the proximal end of the first endplate and the proximal end of the second endplate in the collapsed position. a frame having a longitudinal axis, and having at least one ramped surface; a first endplate configured to engage a first bone of the joint, and having at least one ramped surface mateable with the at least one ramped surface of the frame, whereby when the first endplate is moved relative to the frame in a direction along the frame longitudinal axis, at least one end of the first endplate is moved in a direction away from the frame to open the spacer; a second endplate configured to engage a second bone of the joint; a link moveable with respect to the frame, the link having a projection pivotally engageable with the first endplate to thereby move the first endplate along the frame longitudinal axis when the link is moved with respect to the frame; and an actuating screw (110A-E) moveable with respect to the frame and connected to the link to cause movement of the link when the actuating screw (110A-E) is moved with respect to the frame, characterized in that the spacer is moveable from a collapsed position to an open position, wherein a distance between a distal end of the first endplate and a distal end of the second endplate in the open position is greater than the distance between the distal end of the first endplate and the distal end of the second endplate in the collapsed position and wherein a distance between a proximal end of the first endplate and a proximal end of the second endplate in the open position is less than or equal to the distance between the proximal end of the first endplate and the proximal end of the second endplate in the collapsed position.