Introduction: Asymmetrical cranial vaults resulting from external forces on an infant's head can be caused by abnormal sutural development (synostotic plagiocephaly) or abnormal external forces acting on an intrinsically normal, developing cranium (deformational plagiocephaly).
Discussion: The incidence of posterior plagiocephaly has increased dramatically since the initiation of the "Back to Sleep" campaign against sudden infant death syndrome. The majority of cases are due to deformational plagiocephaly, but rigorous diagnostic evaluation including physical examination and radiological imaging must be undertaken to rule out lambdoid synostosis in extreme or refractory cases.
Conclusion: Unique clinical features and radiological examination using computed tomography technology are helpful in confirming the correct cause of posterior plagiocephaly. Plagiocephaly is considered a benign condition, but with the recent increase in cases, new studies have revealed developmental problems associated with cranial vault asymmetries. Treatment of positional/deformational plagiocephaly includes conservative measures, primarily behavior modification, and, in some cases, helmet therapy, whereas lambdoid synostotic plagiocephaly requires surgical intervention, making differentiation of the cause of the asymmetry critical.