A flexible locking arm for use in an organ manipulator apparatus. The flexible locking arm has a flexible state, used to position the organ manipulator as needed, and a fixed state for mounting the manipulator in a desired orientation. Even in the fixed state, the organ manipulator maintains a limited freedom of movement, to allow the organ held to continue to move substantially according to its natural motion during functioning. For example, in an embodiment where a suction member exerts suction to retract a beating heart and suspend it in a retracted position during surgery by setting the flexible arm to the fixed state, as the retracted heart beats, a complaint joint allows it to expand and contract freely (and otherwise move naturally) at least in the vertical direction so that hemodynamic function is not substantially compromised.