Use a soft tape measure to circle around the head, passing over the arch of the eyebrow and the highest part of the occipital ramus, and the length obtained is the head circumference.
Fix the tape measure to the upper edge of the left eyebrow arch (under the forehead, where the eyebrows are long, protruding like a bow), then pass the upper edge of the left auricle, pull the tape measure to the back of the head of the occipital bone (located in the middle of the back of the head, a piece of raised bone), and finally pass the upper edge of the right side of the back of the ear to return to the upper edge of the right side of the eyebrow arch, and finally back to the starting point, the length obtained is the circumference of the head.
Generally, the head circumference of a newborn baby is about 34cm, and within two years after birth, the head circumference can increase by more than ten centimeters, reaching about 48cm. This is a normal physiological phenomenon, because of the rapid development of the brain, so the head circumference also grows rapidly.
Adult head circumference is about 53cm, the brain will not develop again after adulthood, the head circumference is basically fixed. Therefore, measuring head circumference in adulthood has no great clinical significance.
Children within 2 years of age can have their head circumference measured at regular intervals, and if abnormalities are found, they need to go to the hospital for a detailed examination.