Fig. 1

Assessment of fascicle differentiation, fascicular ratio (FR), and roundness. (A–C) Fascicle delineation on cross-referenced histological sections (HCS), magnetic resonance microscopy (MRM), and high-resolution ultrasound (HRUS) images. Fascicles delineated in yellow indicate single fascicles (SF), and green highlights fascicular clusters (FC) on MRM and HRUS. One fascicle outlined in red is classified as non-depicted (ND), as it is not visualized on HRUS. (D) Calculation of FR, defined as the ratio of the total cross-sectional area (CSA) of all fascicles (purple) to the nerve CSA (black). (E) Calculation of fascicle roundness, with CSA and major axis length delineated.