part of overlaps adult adult circulatory system adult dorsal vessel Dorsal vessel of the adult. It extends from the sixth abdominal segment to the dorsal anterior region of the brain (Curtis et al., 1999). The anterior portion, which is devoid of ostia, is the aorta, whilst the posterior (caudal) region, which has ostia, forms the heart proper. fly_anatomy.ontology FBbt:00003152 dorsal vessel