March baby leg lines asymmetry is common in the following cases: 1, belongs to the normal phenomenon. Baby leg pattern asymmetry in the middle of the thigh, one side of the leg pattern, the other side is not, most because the baby obese, double lower limbs without support weight caused by most no abnormalities, X-ray radiographs belong to normal phenomenon. 2, congenital hip dislocation can also appear hip pattern asymmetry, sometimes accompanied by double lower limbs leg length or thickness, X-ray radiographs can be clear, if necessary to give orthopedic or surgical treatment. 3, congenital Femoral head dysplasia. Most of them have leg pattern asymmetry and one side muscle strength is lower than the other side, which can be clarified by X-ray, and most of them can be corrected by orthopedic brace within one year old.