The human head becomes formed by the late teens or early 20s. It grows steadily from birth, along with the rest of the bones in the body, until the development of the skeletal structure is complete. However, the shape of the head continues to change over the remainder of a person’s life. Although the head does not get much larger, skulls never completely stop changing throughout a person’s life.
A human’s cheekbones become drawn back as the forehead shifts forward. As cranial bones continue to shift throughout the decades, the skin and muscle connected to the bones move with them. The facial
bones also move forward, causing a person’s outer appearance to slowly change.
When considering the growth rate of the human head, a distinction needs to be made between the neurocranium, which is the part that houses the brain, and the visceral cranium, which is essentially the outer structure and face. The neurocranium grows quickly during a child’s early development and usually becomes fully developed by the age of three. A young child’s head is almost entirely neurocranium. The visceral cranium, on the other hand, grows at a much slower rate and is the part that never stops changing.