Introduction: Intracranial hypertension due to craniosynostosis is a dreaded potential complication that affects the developing brain. We hypothesized that craniosynostotic patients have significantly reduced jugular foramen (JF) when compared with age-matched controls. This may partially account for the observed increase in intracranial pressure (ICP) seen in some of these patients. We also estimated the potential effects on ICP using the Hagen-Poiseuille equation. Materials and Methods: Two institutional review board-approved groups were included in this study. Group 1 consists of 14 randomly selected craniosynostotic patients (7 boys and 7 girls; mean age, 9.33 mo; range, 0.6-21 mo). Group 2, the control group, consists of 27 children without craniosynostosis (13 boys and 14 girls; mean age, 8.71 mo; range, 0.23-45 mo). The same neuroradiologist used axial computed tomographic scans to measure the greatest anterior-posterior (AP) and lateral diameters of the jugular bulb. Results: The right JF AP diameter is 23.02% smaller in group 1 than in group 2 (P = 0.0066, 2-tailed t-test). The left JF AP diameter was also smaller for group 1 but was not statistically significant (P = 0.257, 2-tailed t-test). Group 1 also had a nonsignificant increase in both lateral diameters (P > 0.05). Discussion: The study showed a significant decrease (23.02%) in the right JF AP dimension in children with craniosynostosis. On the basis of the Hagen-Poiseuille equation, a 23.02% AP diameter reduction in 1 JF may theoretically increase the ICP 63.5% or 6.35 mm Hg, keeping all other variables, such as blood flow, constant. Although not supported by aspect ratio analysis, the slight increase in the lateral diameters of the patients' JFs may lessen this effect.