abnormal hippocampal commissure morphology decreased hippocampal commissure size MP:0008222 MPheno.ontology decreased size of hippocampal commissure reduced size of commissure fornicis reduced size of commissure hippocampi reduced size of commissure of fornix reduced size of delta fornicis reduced size of hippocampus commissure reduced size of the triangular subcallosal plate of commissural fibers resulting from the converging of the right and left fornix bundles which exchange numerous fibers and which curve back in the contralateral fornix to end in the hippocampus of the opposite side reduced size of ventral hippocampal commissure reduced size of vhc