In the past, people who help relatives but not reason often say a common saying is “elbow to the inside”, in fact, the elbow is not to the inside, it is actually mildly to the outside. If you don’t believe me, you can stretch both upper limbs forward, palms up, and then you can clearly find that the elbows are really turned outward, which is clinically called “carrying angle”. If the elbow really turns inward, it is an abnormality called elbow inversion, except for a few due to congenital reasons, most of them are the sequelae of childhood elbow fracture. The supracondylar fractures on both sides of the elbow (what we call “medial epicondyle” and “lateral epicondyle”) are common. After healing of these fractures, elbow inversion may occur. The obvious manifestation of elbow inversion is that the affected limb slaps the buttocks when walking, and it will lead to the weakening of the muscles governing the movement of the elbow joint, deviation of the direction of force, weakness and inconvenience in lifting objects, and for a long time, traumatic arthritis may occur, causing pain. If elbow valgus exceeds the normal range, it is another deformity – elbow valgus, which occurs for similar reasons as elbow valgus. In addition to unsightly appearance, elbow flexion and extension or forearm rotation dysfunction may occur, traumatic arthritis can also occur, especially serious is that there is ulnar nerve passing through the inner posterior side of our elbow joint, if the elbow inversion is serious, the ulnar nerve is stretched, compressed and rubbed for a long time, which can cause chronic nerve damage, causing hand muscle atrophy, activity disorders, some skin sensory dullness, etc., called delayed ulnar neuritis. It is called delayed ulnar neuritis. Elbow inversion and elbow valgus are mostly seen in adolescents and should be treated orthopedically in hospital by surgical osteotomy according to the type and degree of deformity, and the bone will grow well in about a month, and with functional exercise, the elbow joint will soon return to function. In case of delayed ulnar neuritis, the ulnar nerve can be “moved” from the back to the front to prevent further strain injury. In fact, the growth and development of the upper extremity is mainly done by the bones of the shoulder and bowl, and the elbow is the one that plays a role. To prevent elbow inversion and elbow valgus deformity after fracture, the main thing is to prevent elbow injury in childhood, and after the injury, we should go to the hospital for doctor’s consultation in time for anatomical reset of fracture.