Figure 3.

Axial T2-weighted image of the left wrist (A) shows bulbous enlargement of the median nerve at the level of distal radioulnar joint (solid white arrow). Axial STIR (B) image of the right wrist shows bulbous enlargement of the median nerve (dotted white arrow) at the level of the pisiform, appearing heterogeneously hyperintense. Axial STIR (C) image shows flattening and angulation of the median nerve (dashed white arrow) at the level of the hook of hamate (H). Axial T1-weighted image (D) shows palmar bowing of the flexor retinaculum with raised bowing ratio of 21° (normal < 15°). Thenar muscles show a marked decrease in bulk with T1 hyperintensity (black arrow) within, suggestive of fatty atrophy