abnormal hindbrain size increased hindbrain size expanded hindbrain expanded rhombencephalon csmith enlarged rhombencephalon 2013-11-14T09:53:41Z MP:0012265 enlarged hindbrain MPheno.ontology increased rhombencephalon size greater than average size of the part of the brain developed from the posterior of the three primary brain vesicles of the embryonic neural tube from which the metencephalon and myelencephalon are derived