What is funnel chest? Funnel chest is the most common chest wall deformity in children, which refers to a congenital thoracic deformity in which the lower part of the sternum is depressed inward and the adjacent rib cartilage is also depressed with it, forming a funnel-like appearance. The incidence is about 1-7/1000. The cause and danger of funnel chest The cause of funnel chest is still unclear, but it is generally believed to be a congenital developmental abnormality, some scholars believe that it is caused by the overgrowth of rib cartilage, and the overgrown rib cartilage bends backward, causing the chest wall to be depressed to form a funnel chest. The inward depression of the sternum squeezes the important organs of the chest cavity such as the heart and lungs, resulting in restricted growth of the thoracic organs, which can lead to recurrent respiratory infections such as colds, coughs, fevers, decreased activity tolerance, and shortness of breath. As children grow older, some serious complications such as scoliosis, asymmetrical funnel chest, sternal torsion, etc. may occur after school age. In addition to the physiological effects of funnel chest on the child, it can also cause greater mental burden and psychological stress to the child and parents. These children are often ashamed to expose their foreheads, refuse to wear tank tops in summer, are afraid to go swimming, are introverted and withdrawn, etc. Third, the grading of funnel chest is generally divided into light, medium and heavy. There are two general methods of grading: 1. Funnel Index (FI): FI=(a*b*c)/A*B*C (a: length of depression, b: width of depression c: depth of depression A: length of the sternum B: transverse diameter of the thorax C: shortest distance from the most concave part of the sternum to the front of the spine) 2. CT Index (Haller Index): transverse diameter of the thorax at the lowest point of depression / distance from the lowest point of depression to the front of the spine. In normal people the average index is 2.52, <3.2 mild, 3.2 to 3.5 moderate, and 3.5 severe.