An essential feature of mammals and particularly primates is the marked increase in brain volume that occurs following delivery. Head circumference increases from 35 cm at birth to 50 cm by age 3 yrs (average adult head circumference is just 5 cm more). This dramatic postnatal brain volume growth requires that the bones not be fused at birth to facilitate vaginal delivery and that fusion of cranial sutures occurs after age 2 yrs. Accordingly, premature fusion of cranial sutures may have an effect on cranial shape and less frequently on brain growth (primary craniosynostosis).
Abnormalities of head shape are a frequent concern of parents, particularly since the infant head is relatively larger than the adult head. Appropriate recognition and evaluation is important to manage craniosynostosis.
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Diagram of a neonate's skull demonstrating the location of the sutures.
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Frontal view showing a fused and ridged metopic suture on 3-dimensional CT.
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CT image demonstrating features of secondary craniosynostosis with cerebral atrophy. Cerebral atrophy is not present in primary craniosynostosis.
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Positional molding. Note the anterior displacement of the right occiput and of the right frontal region on the same side, which differentiate positional molding from posterior plagiocephaly craniosynostosis.
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Posterior view of 3-dimensional cranial CT demonstrating early fusion of the lambdoid suture.
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Isolated fusion of the metopic suture. Note that the remaining sutures are open.
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Trigonocephaly. Note the triangular shape of the head.
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Infant with primary craniosynostosis. The specific deformity of the skull is Kleeblattschadel or cloverleaf skull.
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Skull deformities associated with single suture synostosis.
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Positional plagiocephaly. Note anterior position of the ear on the side with occipital flattening.
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Sagittal synostosis and the associated scaphocephaly seen on skull radiograph and 3-dimensional craniofacial CT scan.
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Sagittal synostosis before and after cranial vault surgery and the associate improvement of scaphocephaly.
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Unilateral coronal deformity with retrusion of the orbit and harlequin eye deformity. Note the ipsilateral deviation of the nasal radix and the contralateral deviation of the nasal tip.
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Fusion of coronal sutures bilaterally. Note the increase transverse dimension and retrusion of the orbital rim.
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Intraoperative view of bilateral coronal synostosis. Note the decreased anterior-posterior dimension, increased transverse width and retruded orbital rim.
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Pre- and postoperative photos of metopic synostosis. Note the prominent forehead keel corrected after surgical repair.