part of part of organ part compact bone tissue bone tissue osteon haversian systems NCIT:C32714 haversian system UBERON:0014730 osteonum FMA:32693 volkmann's vessel SCTID:361726004 Wikipedia:Osteon haversian canal BTO:0004592 bone matrix haversian system A circular structural unit of bone tissue. It consists of a central hole, the Haversian canal through which blood vessels run, surrounded by concentric rings, called lamellae. MESH:D006253