The anterior and the posterior fontanelles is made up of the MESENCHYMAL CONNECTIVE TISSUES.
The anterior and the posterior fontanelles are two areas that are normally found on infant heads; at these areas, the skull bones did not cover the brain completely. The anterior fontanelles is located towards the front of the head while the posterior fontanelles is located at the back of the head. As the baby grow older, the mesenchmal tissues of the fontanelles turns into bone tissues.