Fig. 2. Direct muscle stimulation, during which stimulating and recording electrodes are both placed in the muscle. In critical illness neuropathy, compound muscle action potentials are reduced or absent after conventional nerve stimulation but normal after direct muscle stimulation. In critical illness myopathy, compound muscle action potentials are reduced or absent after both conventional nerve stimulation and direct muscle stimulation. Reproduced with permission from Zink et al. and Macmillan Publishers Ltd: Nature Review Neurology, 2009.20