In the clinic, we often meet parents who bring their babies to the clinic, saying that the doctor has suggested that the buttock pattern is asymmetrical and they need to see a specialist. The parents are usually very nervous, especially worried that the baby may have some serious problems. The doctor will explain that the asymmetry of the lines indicates that the baby may have hip problems and will walk with a limp in the future! So, what is the reason for the asymmetry of the baby’s leg/hip lines? Usually, the skin lines of the baby’s lower extremities should be symmetrical, that is, the skin lines on the front or the back of the buttocks should be at the same level. There are two cases of asymmetric leg/hip lines: one is the abnormal development of the baby’s hip joint, especially unilateral subluxation or total subluxation, which simply means that the femoral head is not in its own nest and has gone outside, so that the femoral head that stays in its nest is not at the same level as the opposite one, and naturally the skin lines will not be symmetrical. In the other case, the hip joint is normal, but only the natural asymmetry of the skin pattern. This is because in about 30% of babies with normal development, the hip/leg pattern can be asymmetrical. It is important to be alert to the fact that a baby with bilateral total subluxation can have a symmetrical pattern. Therefore, it is not entirely scientific to simply emphasize the symmetry of the striae. A physical examination by a pediatric orthopedic specialist is needed and, if necessary, appropriate ancillary tests, such as ultrasound or X-ray, are chosen according to the age of the baby. So, what are some of the symptoms that a baby with abnormal hip development may have in addition to leg pattern asymmetry? The most common one is limited hip abduction, which is usually what we parents talk about when we can’t press the leg down. Under normal circumstances, when the hip joint is flexed and abducted, the baby’s thighs can be close to the bed, and both sides are symmetrical. If the baby’s bilateral abduction is not symmetrical, one side can be close to the bed surface, but the other side can not, it indicates that the baby’s hip joint development is more likely to be abnormal. The lower limbs are not equal in length, and in babies with hip dislocation or subluxation, the two legs are not the same length. Parents sometimes find this when bathing and need to pay special attention and go to a specialist for examination. In addition to asymmetry of the leg/hip pattern, limited hip abduction and unequal length of both lower limbs, there are also other clinical symptoms that need to be examined by a pediatric orthopedic surgeon and, if necessary, confirmed by ultrasound or x-ray. Early diagnosis of hip joint abnormalities is necessary so that early treatment can be given to the baby and the hip joint can be restored to normal at an early stage without affecting the toddler and walking.