The relationship between basic multicellular unit activation and origination in cancellous bone.

Activation frequency is often used as a measure of basic multicellular unit (BMU) activity in cancellous bone. However, activation frequency expresses the rate of BMU appearance in a histologic slide and not the rate of origination, which is a more physiologic indicator of remodeling activity and is necessary for the development of BMU-level bone remodeling simulations. Using identical assumptions to those for calculating the activation frequency, it is shown that the origination frequency in cancellous bone is equal to the activation frequency divided by the total distance traveled by the BMU and its width.