Figure 4.

Collagen fiber orientation. Picro-Sirius stained sections from the human cervix. (A) Longitudinal section of a biopsy including epithelium (Bar: 500 μm); (B) collagen fibers in the center of the grid were divided into three categories based on their orientation (longitudinal axis of sections horizontal): 1) longitudinal or "parallel" fibers (deviating less than ± 45° from the longitudinal axis), 2) perpendicular fibers, (deviating between 46° and 90° or -46° to -90° from the longitudinal axis) representing circular or radial fibers, and 3) fibers shorter than 27 μm (not oriented parallel with the sectioning plane) representing circular, radial or wavy longitudinal fibers (arrows point at a longitudinal collagen fiber. Bar: 25 μm).