The esthetic success of sagittal synostosis reconstruction is measured by cephalic index (CI). This limited measure does not fully account for the abnormal head shape in sagittal synostosis. In this retrospective study, we investigate a new objective measure, point of maximum width (PMW) of the skull from a vertex view, to determine where the head is widest for children with sagittal synostosis as compared with normal controls. Preoperative computed tomography (CT) scans of 27 children with sagittal synostosis and 14 postoperative CT scans at least 8 months after surgery were obtained. Normal CT scans were matched for age, sex, and race. Three-dimensional renderings were standardized for orientation. Mean (SE) PMW in patients with sagittal synostosis was 53% (1%) compared with 57% (1%) in controls (P < 0.001). Mean (SE) CI in patients with sagittal synostosis was 66.8% (0.8%) compared with 83.3% (1.0%) in controls (P < 0.001). The correlation between PMW and CI was weak in both controls (r2 = 0.002, P = 0.824) and uncorrected cases (r2 = 0.083, P = 0.145). After surgical correction, both CI and PMW significantly improved. Mean (SE) PMW in patients after surgical release of sagittal synostosis was 58% (1%) compared with 58% (1%) in controls (P = 0.986). The PMW is not a surrogate for CI but is a novel, valid measure of skull shape, which aids in quantifying the widest region of the skull. It is significantly more anterior in children with sagittal synostosis and exhibits a consistent posterior shift along the cranium after surgery, showing no difference compared with healthy children.