Fig. 1.

Lower limbs involvement in different stages of NLSD-M. T1-weighted images of lower limbs in NLSD-M patients of different severities: a P10, 74 years; b P1, 62 years; c P9, 25 years; d P6, 52 years; e P4, 45 years. Gluteus minimus, semimembranosus, gastrocnemius medialis and soleus are constantly affected muscles even if in different extents. Leg muscles are invariably more affected than thigh. Posterior compartment of both leg and thigh show more severe involvement than anterior compartment. Psoas, biceps femoris (short head) and rectus femoris show a mild involvement in late-disease course. Gracilis and sartorius are constantly spared