Brachycephaly

The term "brachycephaly" is derived from the Greek words "brakhu" (short) and "cephalos" (head), which translates to "short head." Brachycephaly is an infant skull deformity characterized by a lower-than-normal ratio of the skull's length to its width. Infants with this form of skull deformity have a flattening of the cranium's occipital aspect; there is an apparent shortening of the skull in the anteroposterior dimension (length). Brachycephaly may be positional (non-synostotic) or synostotic. The incidence of infant positional skull deformities has increased since 1992. The rising incidence appears to be related to the introduction of the measure of infant supine sleep positioning by the American Association of Pediatrics as a means to prevent sudden infant death syndrome (SIDS). However, brachycephaly in infants can also occur due to craniosynostosis. The infant skull has the dual function of protecting the brain and allowing for its volumetric growth and development. Infants' cranial vault or calvaria comprises several bones separated by fibrous joints or cranial sutures. There are 2 frontal bones separated by a metopic suture and 2 parietal bones separated from each other by a sagittal suture. A coronal suture separates the 2 parietal bones from the 2 frontal bones, which includes the anterior fontanelle (future bregma). Paired squamosal sutures separate paired temporal bones on either side of the calvaria from the 2 parietal bones, and a lambdoid suture, which includes the posterior fontanelle (future lambda), separates a single occipital bone from the 2 parietal bones. The anterior fontanelle typically closes by 3 years old, while the posterior fontanelle usually closes by 3 months old. Craniosynostosis refers to the premature mineralization and fusion of one or more of these fibrous joints, which occur between the bones of the calvaria before the completion of brain growth and development in infants.