Chiari malformation is considered a congenital condition, although acquired forms of the condition have been diagnosed. Chiari malformations are often detected coincidently among patients who have undergone diagnostic imaging for unrelated reasons.
Immediately following birth, the baby’s brain undergoes an extremely rapid phase of growth and development. It is calculated that the volume and size of the newborn’s brain will double in size in nine months and triple in size in 36 months. In order to accommodate such rapid brain growth, your baby’s skull cap must expand rapidly as well. Rather than being one single large piece of bone, his/her skull is made up of several bones (frontal, parietal, occipital, squamosal) which are held together by fibrous-like hinges called “sutures.” These sutures respond to brain growth by “stretching” and producing new bone, thereby allowing the skull to grow along with the underlying brain.
Should any of these sutures close or fuse during early months after birth while the brain is growing, craniosynostosis occurs. The term cranial stenosis or simply synostosis are used to describe this condition. Because the brain is normal, it continues to grow at its programmed rapid rate. However, the closed suture delays proper and parallel bone growth which leads the brain to take the path of least resistance and ultimately the shape of the brain, skull and even face become distorted. Each suture premature closure will lead to a specific abnormal head shape and unique set of problems.