Zebrafish Anatomical Dictionary

Structure description: Hemal arches (of preural centra)

by Paula Mabee and Nathan C. Bird

Name: Hemal arches (preural)

Abbreviation: ha(pu)

Synonyms: none


hypurals (larval, 5.8mm)

hypurals (adult)

Description: Specialized preural hemal arches and spines.
Hypurals: The hypurals are expanded and laterally flattened hemal arches and spines. They support the lepidotrichia of the caudal fin. The hypurals form ventral to the posterior tip of the dorsally-flexed notochord. In zebrafish condensations of the hypurals begin forming at approximately 6 dpf (4.1 mm NL, notochord length).
Parhypural: Hemal arch and spine of preural centrum 1. The parhypural is defined as the most posterior hemal arch with an open canal through which the ventral aorta passes. The parhypurapophyses (also "hypurapophyses") are the paired bony lateral extensions off the hemal arch of the parhypural. They serve as origin for the anterolateral bundle of the hypochordal longitudinal muscle (Lundberg and Baskin 1969).
Unlike the other (more anterior) hemal arches and most neural arches, the hemal arches of the preural centra form autogenously, with the remaining undergoing intramembranous ossification. The cartilaginous precursors of the hemal arches of preural centra 1 and 2 develop as blocks on the ventral surface of the preural centra. These arches will eventually fuse with the hemal spines.



Parents (forms from): sclerotome


Group (member of):