If the left and right legs are symmetrical with no special discomfort symptoms, it is considered to be due to congenital developmental abnormality. It may also be due to the patient is particularly thin, localized subcutaneous fat is too small. In adolescents, the herniation of the fibular tuberosity may be caused by X-shaped leg or O-shaped leg, resulting in knee valgus. All of the above are physiologic factors and generally do not require special treatment. If the protruding part has obvious pain or swelling and other symptoms, we should consider the possibility of pathologic factors, on the one hand, it may be due to local osteochondroma, or bone cysts leading to bone lesions, which need to be clearly diagnosed through X-ray examination. On the other hand, it may be due to local sebaceous adenoma, or lipoma and other soft tissue lesions, which need to be clearly diagnosed by local ultrasound examination. The protrusion of the fibular tuberosity in middle-aged and elderly patients is mostly due to osteophytes.