The inability to cross the right leg may be due to the following reasons: 1. contracture of the right hip joint, there are many possible reasons for this condition, such as the existence of previous hip trauma, resulting in contracture of the hip capsule; due to the existence of internal inflammation of the hip joint, such as synovitis or osteoarthritis, resulting in reduced mobility of the hip joint, then the above symptoms will occur. 2, caused by trauma to the right side of the hip. For example, if there is a fracture or dislocation of the right hip, the above symptoms will occur. 3, a series of neurological sequelae, such as the sequelae of cerebral palsy, polio sequelae, etc., may appear the right hip can not cross the legs of the symptoms. 4, the hip or sacroiliac joint inflammation caused by, for example, there may be ischemic necrosis of the femoral head inside the hip joint, sacroiliac arthritis, Sacroiliac arthritis. These inflammatory diseases may lead to a decrease in the mobility of the patient’s hip during the attack, which may lead to the above symptoms.