You are working as a medic at a gymnastics competition, and one of the gymnasts has a bad landing after a vault, injuring her leg. Her leg is bent at an awkward angle and her tibia and fibula are obviously fractured. you palpitate her posterior tibia and dorsalis pedis pulses on her non-injured limb and they are 2/4. However, on her injured limb, they are 0/4. you also notice that her injured limb is becoming pale and cold to the touch distal to the injury. What has likely happened? Explain.