Genetic and electrodiagnostic testing have long been standard diagnostic testing methods for peripheral nerve lesions. Ultrasound examination can be considered as a complementary test and has the advantage of obtaining detailed morphological information about peripheral nerves. Morphological information such as peripheral nerve cross sectional area (CSA), which can be obtained using ultrasound, is useful in evaluating peripheral nerve lesions such as entrapment neuropathy and inflammatory polyneuropathy. In this paper, I would like to briefly introduce existing meta-analysis studies on the normal value of peripheral nerve CSA to provide information for standardization of nerve examination on ultrasound.