Butterfly bone protrusion in 12-year-old girls may be due to long-term hunchback, malnutrition, winged scapula and so on. 1. Long-term hunchback: If a 12-year-old girl hunches over for a long time, making the back spine overly curved, it can lead to butterfly bone protrusion. 2. Malnutrition: When 12-year-old girls suffer from malnutrition due to excessive weight loss or anemia, it can cause the fat layer around the butterfly bone to be too thin, making the butterfly bone protrude. 3. Pterygoid scapula: if 12-year-old girls have damage to the long thoracic nerve and parasympathetic nerve due to long-term strain or disease, which paralyzes the anterior serratus and trapezius muscles, resulting in the butterfly bone not being able to tightly adhere to the chest wall, the pterygoid scapula, or butterfly bone protrusion, will occur. Butterfly bone protrusion in 12-year-old girls, there may also be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.