The inability to turn the foot upward may be related to the following reasons: 1. There may be injuries to the peripheral nerves, such as fractures of the head and neck of the fibula, which may lead to damage to the common peroneal nerve or part of the nerve below it, and then paralysis of the muscles on the front and outside of the lower leg, resulting in foot drop and inability to turn the foot upward. 2. This condition may be caused by damage to the muscles and tendons around the calf and ankle joint, such as knife cuts and serious soft tissue blunt contusions, which may lead to weakness in hooking the toe and dorsal extension of the foot, resulting in limited movement. 3. If the ankle joint is severely traumatized, or if there is osteoarthritis or traumatic arthritis, the joint mobility may be greatly reduced. In this case, if the patient extends the ankle joint dorsally, i.e., hooks the toe, he or she will often feel a limitation of movement.