Malnourished children have a later chest circumference exceeding the head circumference due to poorer development of chest muscles and fat, which, in addition to nutritional factors, is related to the lack of emphasis on crawling and thoracic exercise. Chest circumference is the length of the nipple around the circumference of a week with a soft ruler. People than the body to see the “three circumference”, buy clothes to measure “three circumference”, identify certain diseases also need “three circumference” indicators. In contrast, the baby’s body from top to bottom is like a “tube”, there is really nothing “three circumference” can be said. Beijing Baodao Maternity Hospital experts said, in fact, the child also has a “three circumference”, but this “three circumference” is not his “three circumference”, that is, head circumference, chest circumference and abdominal circumference. First, the head circumference from birth to 2 years old, head circumference growth rate is very fast, 2 years old after the slowdown. Parents can use a soft ruler from the child’s eyebrows above a point to the back of the most prominent point of the brain around the circle measurement, usually newborns for 34 centimeters, 6 months for 43 centimeters, 1 year for 46 centimeters, 2 years for 48 centimeters. A head circumference that is too large or too small may indicate disease. If the head circumference is less than 2 standard deviations for babies of the same age and gender, and the ability to hold up the head, sit and stand, walk and speak cannot keep up with that of babies of the same age, it means that the brain development of the baby may be delayed. At this point, you should go to the hospital to have your baby’s development evaluated and have his/her intelligence tested. In addition, head circumference needs to be measured regularly. If your baby’s head circumference grows suddenly faster during the normal growth period, you should also suspect whether it is caused by a disease. In particular, if there is irritability, crying, vomiting, headache, convulsions, eye slanting or eyeballs can not look up, etc., we should be more vigilant, in order to prevent the child from suffering from hydrocephalus, brain tumors and other diseases. Because the chest cavity is mainly filled with heart, liver and lungs, the growth of chest circumference is very much related to physical development. When a child is born, the chest circumference is smaller than the head circumference by 1-2 centimeters, the head circumference is equal to the chest circumference from 12 months to 21 months old, and the chest circumference exceeds the head circumference after 21 months. In malnourished children, the chest circumference exceeds the head circumference later due to poorer development of chest muscles and fat, which, in addition to nutritional factors, is also related to the lack of emphasis on crawling and thoracic exercise. Chest circumference is the length of a week around the flat nipple with a soft ruler. It is 32 centimeters for a newborn, 44 centimeters at 6 months, 46 centimeters at 1 year, and 49 centimeters at 2 years. If you notice a significant depression or bulge in your child’s chest, you should have it checked by a doctor as soon as possible. Some diseases can cause chest deformity, such as rickets can form chicken breast or funnel shape, some serious congenital heart disease can make the left side of the sternum bulging. Third, abdominal circumference The child’s abdominal circumference is easily affected by intestinal changes, the normal range of expansion and contraction is very large. Healthy children can not be measured, the abdomen is abnormally large (such as ascites children) should be measured regularly for comparison. Significant chronic abdominal elevation may be due to rickets, tuberculous peritonitis and megacolon. Significant abdominal subsidence may be due to wasting and dehydration. However, it should be reminded that there is a slight difference between men and women, and it is best for parents to measure the head and chest circumference of their children at a regular specialist hospital. It is recommended that babies before the age of 6 months should be measured once a month at a specialist hospital; babies between 6 months and 1 year old should be measured once every 2-3 months; and after the age of 1 year old should be measured once every 3-6 months.