Abstract
Interstitial lamellae of cortical bone found in the shafts of long bones are served by systems of canaliculi shaped like a broom. The handle of the broom is crowded by canaliculi which open into a transverse communication between the longitudinal vascular canals of osteons. The existence of these systems of canaliculi has not been previously recorded. Their presence argues against the widely held view that interstitial lamellae are merely the remains of osteons which have been partially resorbed during remodelling of bone. A fresh look at the development of interstitial lamellae needs be taken.