A fontanel is the space created by the joining of two or more sutures. It is covered by thick membranes and the skin on the baby's head, protecting the brain underneath the fontanel from contact with the outside world. Identification of the two large fontanels on the top of the fetal skull helps you to locate the angle at which the baby's head is presenting during labour and delivery. The fontanels are shown in Figures 6.5 and 6.6. They are:
- The anterior fontanel (also known as the bregma) is a diamond-shaped space towards the front of the baby's head, at the junction of the sagittal, coronal and frontal sutures. It is very soft and you can feel the fetal heart beat by placing your fingers gently on the fontanel. The skin over the fontanel can be seen 'pulsing' in a newborn or young baby.
- The posterior fontanel (or lambda) has a triangular shape, and is found towards the back of the fetal skull. It is formed by the junction of the lambdoid and sagittal sutures.