Volkmann's canals, also known as perforating holes or channels, are anatomic arrangements in cortical bones that allow blood vessels to enter the bones from periosteum. They interconnect the Haversian canals with each other and the periosteum. They usually run at obtuse angles to the Haversian canals and contain anastomosing vessels between haversian capillaries. They were named after German physiologist Alfred Volkmann (1800–1878).