Fig. 4

a Focal fusiform thickening of radial nerve is noted (D3 marker) with normal calibre proximally and distally (D1 and D2 markers). The nerve is hypoechoic at the site of enlargement of the nerve. This anatomical abnormality was noted just deep to the scar at the site of bite on the skin. b Short axis view of focal thickening suggestive of radial nerve neuroma (between cross marks) seen distal to the spiral groove. The nerve is seen lying between the brachialis and brachioradialis. c Axial PD fat saturated sequence of the same patient showing a well-defined ovoid hyperintense lesion (black arrowhead) in continuity with the radial nerve. As the lesion was noted distal to the spiral groove, after supply to the triceps, there is no signal intensity change in the triceps muscle signifying normal innervation to the muscle. d Sagittal PD sequence showing a fusiform hyperintense lesion (black arrowhead) corresponding with the ultrasound findings. The scar site on the skin can also be noted (white arrowhead)