Fontanelles and Sutures of the Infant Skull

Topic Overview

A baby's skull consists of five thin, curved bony plates that are held together by fibrous material called sutures . The skull is soft enough so that it can expand as a baby's brain grows. Usually, the area within a baby's skull doubles in the first 6 months of life and doubles again by age 2. Some sutures begin to close at about this time. After age 2, the skull and brain grow at a much slower rate.

The sutures gradually harden (ossify) to join the skull bones together. The spaces where sutures meet are called fontanelles or " soft spots ."

If any of the sutures close too early, it may affect normal skull development, sometimes resulting in a misshapen head or other problems.

Babies born with certain conditions may have irregular fontanelles and sutures. For example, a baby born with congenital hydrocephalus may have wider sutures than normal, and the tissue covering the fontanelles may bulge.