Abstract: Objective To investigate the pathological features of sural nerve biopsy in patients with motor neuron disease （MND）. Methods 22 patients with amyotrophic lateral sclerosis (ALS) underwent sural nerve biopsy and routine electrophysiological examination. The transected images were captured and morphometrically analyzed.Results The myelinated fiber density decreased in ALS patients' sural nerves, and larger fibers were involved mostly. The thinly myelinated fibers increased. Conclusion The sural nerves of ALS patients shows mild but definite pathological changes.

Key words: motor neuron disease, sural nerve, neuropathy, pathology