Human Head Growth

The growth of the human head is a complex process, from the moment of conception all the way through adulthood. Head shape, size and structure change greatly over the years.

Features

The human skull consists of 22 bones. These bones are joined together either by amphiarthroses (slightly moveable joints) or synarthroses (immoveable joints).

Function

Sutures, which are fibrous membranes between the bones, allow for growth and expansion of the skull while it is still developing. Sutures that close too soon can affect head growth and brain development.

Time Frame

The head grows the most from birth to 7 years of age. The first year shows the most increase in the size of the cranial vault because of the amount of brain development during that period.

Normal Growth

According to the National Institutes of Health (NIH), a normal newborn’s head is about 2 cm larger than his chest size. Between 6 months and 2 years old, head size is equal to chest size. After 2 years old, head size is smaller than chest size.

Abnormal Growth

Pediatricians track a child's head circumference because abnormal growth could signal a problem. A large head could be caused by conditions such as Canavan disease, Hurler syndrome, or Morquio syndrome. A small head (microcephaly) could indicate the brain isn't developing properly.

References

• The John Hopkins Hospital: Skull Basics
• National Institutes of Health: Increase head circumference
• National Institutes of Health: Head circumference

Resources

• The Johns Hopkins Hospital: Glossary