A haemal arch is a bony arch on the underside of a tail
The hole so formed is the haemal canal.
It sometimes has a haemal spine on.
The blood vessels to and from the tail run through the arch.
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haemal arch — noun a structure arising ventrally from a vertebral centrum and enclosing the caudal blood vessels • Syn: ↑hemal arch • Hypernyms: ↑arch • Part Holonyms: ↑centrum … Useful english dictionary
haemal arch — the arch which encloses the caudal vein and dorsal aorta and is found on the ventral surface of the more posterior (caudal) vertebrae. In Acipenseridae it is continuous but interrupted in Actinopterygii … Dictionary of ichthyology
haemal funnel — the lengthening of the haemapophyses beyond the bridging of the haemal arch of the posterior abdominal vertebrae where they almost form a second arch but the haemapophyses never fuse, e.g. in Atherinops, Atherinopsis (Atherinidae) … Dictionary of ichthyology
haemal rib — a misnomer for a ventral rib (one of the ribs surrounding and protecting the viscera and articulating with the parapophyses of the vertebrae) based on the fallacy that it was homologous with a haemal arch bone. As some fish have ventral ribs on… … Dictionary of ichthyology
haemal spine — a spine extending downwards from the lower end of the haemal arch in posterior or caudal vertebrae. Also called haemacanth and haemapophysis … Dictionary of ichthyology
hemal arch — haemal arch … Dictionary of ichthyology
hemal arch — noun a structure arising ventrally from a vertebral centrum and enclosing the caudal blood vessels • Syn: ↑haemal arch • Hypernyms: ↑arch • Part Holonyms: ↑centrum * * * noun : a bony or cartilaginous arch extending ventrally from the spinal… … Useful english dictionary
vertebra — (plural vertebrae)) bony or cartilaginous elements surrounding the notochord or replacing it and often protecting the spinal cord and caudal vein. Vertebrae are composed of a centrum formed from two pleurocentra and two intercentra or parts of… … Dictionary of ichthyology
caudal vertebra — one of the posterior vertebrae lacking ribs, found behind the abdominal vertebrae and extending to the tail, each with a ventral haemal arch, canal and spine. The first caudal vertebrae is near the internal, dorsal tip of the first anal proximal… … Dictionary of ichthyology
processus spinosus inferior — (plural processus spinosi inferiores)) haemal spine (a spine extending downwards from the lower end of the haemal arch in posterior or caudal vertebrae. Also called haemacanth and haemapophysis) … Dictionary of ichthyology
