abnormal hippocampal fimbria morphology increased hippocampal fimbria size 2013-12-04T22:39:39Z MP:0012465 MPheno.ontology csmith enlarged hippocampal fimbria greater size of the flattened band of efferent fibers arising from the subiculum and medial border of the hippocampus, which then thickens to form the fornix and fibers of the hippocampal commissure