In an ischemia-induced model of an acute motor neuron disorder, there is anterior horn cell damage with Wallerian degeneration in ventral roots; dorsal root ganglia and dorsal roots are unaffected. In a mixed nerve there is axonal degeneration reflecting loss of motor fibers. The sural nerve is normal showing that it does not contain motor fibers. This observation is relevant to the neuropathology of motor neuron disease where axonal degeneration found in the sural nerve suggests involvement of sensory fibers.