develops from develops from embryonic structure heart primordium cardiogenic plate The first recognizable structure derived from the heart field. myocardial plate VHOG:0000975 UBERON:0004139 heart rudiment cardiac crescent EMAPA:16106 TODO - check plate vs rudiment vs primordium vs endocardial tube. See XAO (In vertebrates) The embryonic mesoderm is the source of both the cardiogenic plate, giving rise to the future myocardium as well as the endocardium that will line the system on the inner side.[well established][VHOG] cardiogenic crescent EHDAA2:0000215