Figure 1. Somatotopy of L5 and S1 lesion patterns at thigh level.

(A) Complete array of representative axial images of the sciatic nerve for each patient, at thigh level 17 cm proximal to the knee joint space. Lesioned fascicles within sciatic nerve are located anterolateral in patients with L5 neuropathy and posteromedial in patients with S1 neuropathy. Images are flipped horizontally from left to right in patients with left-sided affection to obtain comparability. Fibular and tibial divisions are separated from each other since they divide at different levels interindividually. (B) Color-coded spatial map of pathologically increased T2 signal, calculated as the group mean after intersubject image registration with 6 degrees of freedom. Note that, because of the calculation mode by relative signal intensity values, this map serves for visualization purposes alone and not as a fully quantitative probability map.