Measurement of Osteoblastic Activity in Diaphyseal Bone

Fresh undecalcified sections are made and stained with basic fuchsin by Frost's methods. Only complete cross sections cut accurately perpendicular to the diaphyseal longitudinal axis may be measured. The percentage of the longitudinal vessels containing osteoid seams is measured by a counting technique. The average number of longitudinal channels/mm² of the cross section is next measured by a similar technique. Multiplying the seam percentage by the channels/mm² gives the seams/mm². For reasons which are discussed this is equivalent to seams/mm³. A suitable sampling method is used to obtain useful precision.