Fig. 4 in Palatal Biomechanics and its Significance for Cranial Kinesis in Tyrannosaurus rex

Fig. 4. The relationship between fiber length, pennation angle, and force in muscle physiology and its application to reconstructing function in fossil taxa using recent case studies. PCSA is a function of pennation angle and fiber length and is mapped as a heatmap with contour lines. We replotted the regression line from Bates and Falkingham, 2018 (labeled "B&F 2018") showing the classic prediction that increasing pennation in order to accommodate shorter muscle fibers increases PCSA. PCSA values from recent studies, Gignac and Erickson, 2017 (labeled "G&E 2017") and Bates and Falkingham, 2018, of Tyrannosaurus cranial biomechanics are also plotted to show similarities in approaches.