2. Angle between femoral head and articular fossa: The angle between femoral head and articular fossa is normally 90 degrees. When the angle is tilted backward or forward, it will go outside eight or inside eight. 3. The direction of the femoral head leaving the articular fossa: When the femoral head dislocates to the anterior side of the articular fossa due to dysplasia or traumatic dislocation of the hip joint, it will cause the internal splayed walking. If it dislocates on the inside, it will go eight feet away. 4. The position of the painful foot: When one foot is painful and the other foot is not painful or slightly painful, the dog will put the painful foot outward and the other foot inward to balance the strength. At this time, walking will be similar to the shape of the external eight, and problems of hip joint, knee joint, tarsal joint, metatarsal joint or orthopedics may cause pain. He is not a real external surgeon, and the pain may improve after it disappears. 5. Congenital or pathological changes in joint morphology: Congenital deformities of joints or alignment changes between joints caused by ligament rupture can also cause inner eight or outer eight when walking, and some deformities have nothing to do with the lower joint and hip joint, and can also cause inner eight or outer eight.