There are seams between the thighs, there are two common cases, people with legs together and upright, double ankle change position, the normal human thighs will exist a certain gap. There are differences due to different degrees of fatness and thinness, and people with thin body types are more obvious, which is a normal physiological phenomenon. There is also a common case of inversion of the knee, which is often referred to clinically as O-leg, is a human knee deformity, mostly due to congenital development and acquired nutritional deficiencies, as well as trauma and other reasons. If there is no symptom, no treatment can be given, but if the knee is turned inside out and there is knee pain, limited movement and other symptoms of osteoarthritis of the knee joint, you need to go to the orthopedic surgery department of the hospital. Depending on the condition, non-surgical and surgical treatment will be performed.