Periosteal attachment fibers in the rat calvarium.

The anatomical relationships between the fiber tracts and bone lining cells within the rat calvarial periosteum have been studied by electron microscopy. Classical Sharpey's fibers were not observed in this location. Rather, thin unmineralized fibers originating from the periosteum traversed the cambial layer and passed to the bone surface between individual osteoblasts or groups of osteoblasts. The organizational relationship suggests that the osteogenic calvarial cell populations are compartmentalized into domains that might be particularly sensitive and responsive to the biomechanical forces of masticatory muscles.