Plagiocephaly and the cranial dural system
The brain and spinal cord are protected by a 3-layered meningeal (dural) system. It adheres to the surface of the brain and spinal cord and attaches to the inside of the skull. The dura is also anchored at numerous points along the spinal column and finally at the base of the spine. This system contains the cerebrospinal fluid (CSF) that flows through, and around, our brain and spinal cord. CSF is made and re-absorbed at a rate of 20mL/hour and we have 80-150mL at any one time. It is the movement of our cranial bones during breathing, and our sacrum and spine when moving, that encourages the fluid to move within this system. Failure of our cranials and spine to move well may impede this flow.
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.