Figure 37. Ulnar nerve encased by fibromatosis. Photograph (bottom) shows the area scanned. A 22-year-old woman complained of a painful nodule in the hypothenar region of the palm. US scans in transverse (Tr) and sagittal (Sag) views show a lobulated hypoechoic nodule (arrows) encasing the ulnar nerve (arrowheads). The nodule proved to be fibromatosis.