At birth, there are 6 fontanelles (soft spots on the skull). Five of these close within the first two months, however, the anterior fontanelle remains open up to 18 months. Our cranial bones join along what are called “suture lines”. These cranial sutures are maintained through adult life and allow for movement between each of the cranial bones. Diminished movement of our cranial bones often results following birth. The combination of a very soft skull after being confined within the uterus and the birth process may lead to a strain within the cranial dural system. The strain and tension remains in the system and limits the ability of your baby to move freely. They will find a new neutral position for their head and body, and due to the softness of their skull, and back sleeping, it will begin to mould to their favoured side.