Volkmann canals, also known as perforating holes, are microscopic structures found in compact bone. They run within the osteons perpendicular to the Haversian canals

Haversian canals

Haversian canals are a series of tubes around narrow channels formed by lamellae. This is the region of bone called compact bone. Osteons are arranged in parallel to the long axis of the bone...

, interconnecting the latter with each other and the periosteum. They usually run at obtuse angles to the Haversian canals and contain anastomosing vessels between Haversian capillaries. The Volkmann canals also carry small arteries throughout the bone. They were named for German physiologist Alfred Volkmann (1800-1878).