A prospective electromyographic investigation of lower limb muscles in patients with different neurogenic disorders showed that complex repetitive discharges (CRD) were observed predominantly and often only in the iliopsoas muscle. Analysis of the EMG findings in acute and chronic lesions shows that CRD are a feature of a chronic proximal motor axon lesion. Furthermore, the frequently focal occurrence of CRD in the iliopsoas muscle in clinically distal diabetic polyneuropathies suggests that this muscle and its nerves represent a locus minoris resistentiae.