This helps keep the knee "locked" to prevent hyperextension. When the knee is flexed, the posterior cruciate ligament helps prevent posterior slipping movements of the tibia. Why was Emily kept in the hospital overnight for observation? • She was kept in the hospital overnight for observation because of the blow to her head, she decided that it would be better if she spent a night in the hospital , as she was stunned and it took some time for her to regain composure from her fall. If she did hit her head while falling she would be at risk for a serious number of brain injuries. What are the purposes of the rehabilitation exercises Emily is expected to complete? • The purpose of rehab exercises is to strenghten any of the muscles and bones that were damaged during the injury. It will also help with the motion and use of the bones and muscles. If the injury is severe enough to where you wouldn’t be able to use it, it would result to loss of function and the purpose of the joint or ligament