Fig. 10From: Non-visualisation of cavum septi pellucidi: implication in prenatal diagnosis?Pseudo-presence of the CSP: columns of the fornix. Axial ultrasound through the fornix at 25 weeks’ gestation demonstrates its tri-linear configuration, which can be mistaken for a normal CSP. The lateral echogenic lines (solid arrows) result from the lateral margins of fornices while the central line (dotted arrow) represents the interface between the fornicesBack to article page