abnormal hindbrain size decreased hindbrain size 2013-11-14T09:53:41Z MP:0012263 MPheno.ontology csmith decreased rhombencephalon size reduced hindbrain size reduced rhombencephalon size size reduction or truncation 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 small hindbrain small rhombencephalon truncated hindbrain truncated rhombencephalon