Why is the baby's buttocks pattern asymmetrical?

From a clinical point of view, there are two reasons for the asymmetry of the lines on the baby's buttocks. One is a natural phenomenon that will not cause any impact on the body. The other is caused by abnormal development of the hip joints of infants and young children. Therefore, if the mother finds that the baby has asymmetric buttocks lines, she must check it in time. If it is the second situation, surgical treatment must be performed, otherwise it will affect future walking.

1. Is asymmetric buttocks a disease?

Asymmetric buttock lines are one of the early signs of abnormal hip development in infants and young children. Similar signs include tight leg separation, unequal leg lengths, etc. These signals often indicate that the baby may have early hip developmental abnormalities and require further examination by a specialist to determine whether this disease exists.

The medical name of this disease is "developmental dysplasia of the hip", abbreviated as DDH in English. This name is a general term for congenital or developmental structural abnormalities of the hip joint in infants and children, including hip dysplasia, hip subluxation and hip dislocation.

How common is developmental dysplasia of the hip (DDH)? How serious is it?

DDH is the most common musculoskeletal system (pediatric orthopedics) disease known in infancy, and the incidence of the disease is generally believed to be around 0.1-0.3%. This data may not seem significant when viewed alone, but do you know the incidence of breast cancer, which is a serious threat to women's health? In 1992, the incidence of breast cancer in Shanghai was only about 25.6 cases per 100,000 people. The difference is more than a thousand times!

Even with orthopedic surgical correction in severe cases of hip dislocation, some children still find it difficult to avoid sequelae such as unequal length of lower limbs, lameness, limited hip joint movement, and premature traumatic joint injury. Some scholars believe that about half of degenerative arthritis in adult women is caused by DDH that was not discovered in infancy or was not treated satisfactorily.

3. Is DDH congenital? Is it hereditary?

Answer: Usually a certain proportion of suspected DDH cases can be found in the physical examination of newborns, but a certain proportion of these children can recover on their own during their postnatal development. Clinical epidemiology has found that DDH is highly prevalent in regions or ethnic groups where there is a custom of wrapping newborns in "candle wraps" or tying up girls' calves, such as the Indian tribes in North America and parts of northern my country. On the contrary, in Africa or parts of southern my country, where parents hold their children with their lower limbs separated due to hot weather, the incidence of DDH is significantly lower. These phenomena make it difficult for us to explain them in terms of innateness. Therefore, the current medical name uses "developmental hip dysplasia" instead of the previously used "congenital hip dysplasia".

Regarding genetic issues, we have also discovered interesting phenomena in our research and clinical treatment. Some scholars believe that the HOX series of genomes that dominate the development of the lower limbs may be related to the occurrence of DDH, but the specific mechanism of occurrence needs further study. In clinical terms, in Europe and the United States, if DDH occurs in a direct relative, it is considered routine diagnosis and treatment that the child must undergo formal examination by a specialist in the neonatal period. Shanghai is one of the first cities to carry out DDH screening in children's health examinations, and has achieved remarkable results. The number of severe cases in the late stage that require corrective surgery is decreasing significantly year by year.