Figure 1.
Adult rat hearts were harvested, sliced, and stained for cells and collagen to analyze variations in the transmural orientation. (A) Masson's trichrome staining of a transmural block cut from the ventricular wall showing the macroscopic variation in fiber orientation across the wall. (B) Analysis of collagen fiber orientation revealed that the degree of alignment from the epicardial side to the endocardial side had a 100° shift. Adapted with permission from 20. Copyright 2017, National Academy of Sciences.