Figure 6From: A unifying hypothesis for hydrocephalus, Chiari malformation, syringomyelia, anencephaly and spina bifidaHypothetical graph showing the effect of posterior fossa size on the frequency of dysraphic lesions at different levels in males and females. Higher, more severe, lesions tend to be more frequent in females who have a smaller posterior fossa as illustrated by the curve on the left. Lower, less severe, lesions are more frequent in males with a larger posterior fossa, as illustrated by the curve on the right.Back to article page