There are several major categories of diseases that orthopedics looks at. First, diseases of the extremities: such as muscle injury, muscle rupture, tendon injury and bone injury, including the major joints of the extremities of the whole body belong to the category of orthopedic diseases. Second, spine diseases: including lumbar disc herniation, cervical spondylosis, lumbar spinal stenosis, ligament calcification, etc., all belong to the spine category of diseases. Third, pelvic diseases: such as pelvic fractures, pelvic injuries. Fourth, motor system diseases: such as diseases caused by abnormalities of motor function. Fifth, hand and foot and ankle diseases: they belong to hand microsurgery and foot and ankle surgery in orthopedics.