The bones of the human skull are joined by cranial
sutures (see figure 1). The anterior fontanelle is where the metopic, sagittal and coronal sutures meet. Normally the sutures gradually fuse within the first few years after birth. In infants where one or more of the sutures fuses too early the growth of the skull is restricted, resulting in compensation mechanisms which cause irregular growth patterns. Growth in the skull is perpendicular to the sutures. When a suture fuses too early, the growth perpendicular to that suture will be restricted, and the bone growth near the other sutures will be stimulated, causing an abnormal head shape. The expanding brain is the main stimulus for the rapid growth of the skull in the first years of life. Inhibited growth potential of the skull can restrict the volume, needed by the brain. In cases in which the compensation does not effectively provide enough space for the growing brain,
craniosynostosis results in increased
intracranial pressure. Craniosynostosis is called simple when one suture is involved, and complex when two or more sutures are involved. It can occur as part of a syndrome or as an isolated defect (nonsyndromic).
Scaphocephaly In scaphocephaly, the sagittal suture is prematurely fused. The sagittal suture runs from the front to the back of the head. The shape of this deformity is a long narrow head, formed like a boat (Greek
skaphe, "light boat or skiff"). The compensatory head-growth forward at the coronal suture gives a prominent forehead, frontal bossing and a prominent back of the head, called coning. The incidence of scaphocephaly is 2.8 per 10,000 births in the Netherlands; therefore, it is the most common form of craniosynostosis.
Trigonocephaly In trigonocephaly, the metopic suture is prematurely fused. The metopic suture is situated in the medial line of the forehead. Premature fusion of this suture causes the forehead to become pointed, giving the head a triangular shape when viewed from above (Greek
trigono, "triangle"). The incidence of trigonocephaly is 1 - 1.9 per 10,000 births in the Netherlands.
Brachycephaly In brachycephaly, both of the coronal sutures are prematurely fused. The shape of this deformity is a wide and high head. The incidence at birth is 1/20,000. ==Team==