Table 3.

Explanation of Meaning of Confusing Histomorphometry Terms

Term	Explanation
Active versus inactive	Should be more explicit. May indicate the presence of bone cells or imply their vigor.
Resorptive parameters	Precisely which measurement is used should be clearly stated. The best measure of resorption is the osteoclast number or surface.
Eroded surfaces	The eroded surface is composed of osteoclast surface plus the reversal surface and is an unfaithful measure of bone resorption. Treatment with an antiresorptive agent will decrease the osteoclast surface and increase the reversal surface.
Formation parameters	Precisely which measurement is used should be clearly stated. Osteoid is not an index of bone formation because it can accumulate with increased bone formation or from delayed mineralization. The only measure of bone formation is the tetracycline-based bone formation rate.
Coupling and balance	Coupling refers to the appearance of osteoblasts at the site where osteoclasts have recently eroded bone cavities. Balance indicates that the new bone deposited by osteoblasts exactly equals the amount previously removed by osteoclasts.
Osteoblasts and osteoclasts: surface or areal referent?	Osteoblasts and osteoclasts can only be on bone surfaces. The appropriate referent is the bone surface. Only osteocytes are correctly reported per bone area.
Activation frequency	The incidence of new remodeling cycles (which usually refers to cancellous bone) can be estimated by dividing the bone formation rate by the wall width, an index of the amount of bone made by a previous team of osteoblasts.
μCT histomorphometry	This is a misnomer. μCT does not reveal excess osteoid, woven bone, or embedded cartilage cores, features that are easily noted with histologic assessment of the cancellous microarchitecture. The quantification of bone cells and the rate of turnover can only be done by a histologic examination.