FIG 5. MR images obtained in a 42-year-old female patient who presented with a foot drop after splint fixation around the proximal lower leg. This case exemplifies that MR imaging is capable of demonstrating the entire muscle, whereas EMG can only study parts of a muscle.

A, Axial T1-weighted image obtained just below knee level localizes affected muscles.

B, Axial TIRM image obtained at the level of A does not show signal intensity abnormality.

C, Axial T1-weighted image obtained approximately 4 cm below knee level localizes affected muscles.

D, Axial TIRM image obtained approximately 4 cm below knee level shows marked signal intensity increase in the TA, ED, and PL, findings consistent with a peroneal nerve lesion.

Initial needle EMG (not shown) obtained just below the knee level did not reveal denervation; however, follow-up examination further distally showed marked denervation in the TA, ED, and PL muscles.