Revisiting the Cephalic Index: The Origin, Purpose, and… : JPO: Journal of Prosthetics and Orthotics
ment, but reference values and norms are lacking for infants, especially in the first year after birth. Discussion Key publications were reviewed by the authors to provide a narrative review of the 1) origin of the cephalic index (CI), 2) adaptations of the measure over time, 3) anatomical landmarks and alignments used, 4) clinical tools, 5) necessary considerations for different ethnic, sex, and cultural influences, 6) value and limitations of CI measurements, and 7) appropriate use of the CI in the documentation of infant skull deformities. The CI calculation has remained constant since the 1840s, although the cranial shape classifications have changed many times over the years. Conclusions Used in isolation, the two-dimensional (2D) and linear nature of the CI fails to describe the magnitude of the three-dimensional (3D) head deformity. However, the CI can and should be used in conjunction with other 2D and 3D measurements to provide a more detailed description and understanding of