Fig. 2. Myocardial elasticity during embryogenesis. Histograms of elastic moduli (150 locations per sample) determined from quail embryos show two peaks, one indicating passive elasticity of contractile myocardium (E_Stiff) and a softer, second peak (E_Soft) which surrounds the myocardium and increases in frequency with development. Results for normal and infarcted rat myocardium are indicated for comparison (Berry et al., 2006).