abnormal hippocampus morphology abnormal dentate gyrus morphology any structural anomaly of one of two interlocking gyri of the hippocampus formation that contains granule cells, which project to the pyramidal cells and interneurons of the CA3 region of the ammon gyrus MPheno.ontology dentate gyrus dysplasia abnormal dentate gyrus of hippocampal formation morphology abnormal fascia dentata morphology MP:0000812 abnormal area dentata morphology