foramen oral foramen HAO:0000670 The foramen that is located anteriorly/ventrally on the cranium in which the mouthparts are positioned. buccal cavity epistomal opening foramen gnathale fossa of the proboscis mouth mouth cavity mouth opening oral cavity oral fossa porta epistomalis porta epistomatalis praecibarium proboscidial fossa rima oris sipho siphon sypho syphon