abnormal brain commissure morphology abnormal posterior commissure morphology 2011-03-04T10:12:41Z MP:0010893 MPheno.ontology abnormal epithalamic commissure morphology any structural anomaly of the band of nerve fiber tracts that span the longitudinal fissure beneath the habenula of the pineal body and over the cerebral aqueduct, interconnecting the left and right pretectal regions and some midbrain nuclei csmith