Fractured leg bones. Coloured X-ray of a double fracture in the lower right leg of a male patient. Both the thicker tibia (shin bone) and the thinner fibula behind it have broken in the same place. At upper left is the knee, where these bones meet with the femur (thigh bone). Such fractures are usually caused by severe force, such as a fall or a car accident. This fracture was treated by surgical realignment performed under anaesthesia. The bone ends were then immobilised, using metal pins and plates, to allow the broken pieces to reunite firmly. In an adult a weight-bearing bone such as the tibia may take up to six months to knit together completely. See M330/1681 and M330/1682 for the fracture after treatment.