How Does a Skull Grow?
A skull grows in response to the expanding brain, a process primarily driven by internal pressure. The skull's flexible sutures, which are seams between the skull bones, allow for growth in all directions, though slightly more at the back.
The brain's growth is the primary determinant of skull size and shape, especially during the first two years of life. As the brain increases in volume, it exerts pressure on the skull bones, stimulating their growth and expansion to accommodate the increasing size. This growth occurs predominantly through the sutures. [1, 7, 8] [Source: The skull grows and takes shape in response to pressure from the growing brain. The open sutures allow growth in all directions, with a slight preference for growth in the back. Brain growth determines the size and shape of the skull and is most dramatic in the first 2 years of life.]
Sutures: The Key to Skull Expansion
Sutures are fibrous joints between the skull bones. These flexible seams allow the skull to grow and adapt to the expanding brain. Premature closure of one or more of these sutures (craniosynostosis) can result in an abnormally shaped head. [4, 7, 9, 10] [Source: These skull bones are connected to one another by specialized structures called sutures. These sutures look like seams or spaces between the skull bones. The… sutures allow the skull to grow as the baby's brain grows.]
Shape and Growth: A Dynamic Process
The process of skull growth is dynamic. It isn't merely an increase in size but also a shaping process. The skull's shape is directly influenced by the brain's growth pattern. Any factors impacting the brain's development or the sutures can lead to variations in skull shape. For example, positional plagiocephaly, a flattening of the back of the head, can occur due to consistent sleeping position and is generally not a cause for concern. [5, 6] [Source: As the brain grows, the skull must grow in response to accommodate extra volume while providing a tight fit. These are very different growth…; A positional skull deformity does not affect a child's brain development… skull while allowing the head to gradually grow and round out on its…]
Abnormal Skull Growth: Craniosynostosis
Craniosynostosis is a condition where one or more sutures close prematurely. This early closure prevents the skull from growing normally, resulting in an unusual head shape. The severity depends on which sutures are affected. [7, 8, 10] [Source: Craniosynostosis occurs when one or more of the sutures closes early. Early suture closure can cause the skull to grow in an unusual shape.]
