children s health issues
Physical Growth of Infants and Children
Head Circumference
Head circumference is measurement around the largest area of a child's head. Doctors place the tape measure above the eyebrows and ears and around the back of the head. This measurement is important because the size of the head reflects the size of the brain, and this measurement lets doctors know whether the child's brain is growing at a normal rate. Head circumference is routinely measured until children are 3 years old. At birth, the brain is 25% of its future adult size, and head circumference is about 14 inches (about 35 centimeters). By 1 year of age, the brain is 75% of its adult size. By 3 years of age, the brain is 80% of its adult size. By 7 years of age, the brain is 90% of its adult size. 