The quantitative study of the orientation of collagen in compact bone slices

• Published in: Bone (New York, N.Y.) Vol. 11; no. 1; p. 35
• Main Authors: Boyde, A, Riggs, C M
• Format: Journal Article
• Language: English
• Published: United States 1990
• Subjects: Animals; Bone and Bones - ultrastructure; Collagen - ultrastructure; Horses; Image Processing, Computer-Assisted - methods; Reproducibility of Results
• ISSN: 8756-3282
• DOI: 10.1016/8756-3282(90)90069-B

We describe and validate a simple method for the study of the proportion of collagen fibers (and apatite crystals) in a bone slice parallel with the plane of section. Viewed between crossed circular polarizers, all bone areas with collagen lying more nearly in the plane of section (i.e., transverse [TS] collagen) appear bright whatever its direction in this plane; longitudinal [LS] collagen appears dark, but not as dark as the background. The degree of brightness increases with section thickness, which must therefore be standardized--we chose 100 microns plane parallel sections. We transferred the circularly polarized light [CPL] image via a CCD TV camera to an image analyzing computer. Color-coded maps of the CPL image were used to compare regions within and between sections. The new analytical procedure makes more detailed studies of the fine-structural orientation in compact bone possible, but does this have any significance? To answer this question, a bone in which the in vivo strain pattern had been clearly documented was chosen for particular study. Transverse mid-diaphyseal sections of the equine radius showed a distribution of CPL bright areas which correlated closely with previously reported strain patterns.