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Updated: May 12, 2026

Nerve Ultrasound Protocol to Detect Dysimmune Neuropathies
Published on: October 7, 2021
Cross sectional area reference values for sonography of peripheral nerves and brachial plexus
Antonios Kerasnoudis1, Kalliopi Pitarokoili, Volker Behrendt
1Department of Neurology, St. Josef-Hospital, Ruhr University, Bochum, Germany. antonis.kerasnoudis@gmail.com
Objective:
Ultrasound measurements of the cross sectional area (CSA) variability have been recently introduced to quantify pathological changes in peripheral nerves (PN).
Methods:
Reference values from 75 healthy subjects and their correlation to age, height, weight and sex are reported.
Results:
The mean values in PN were: (1) intranerve CSA-variability: median 1.05 (SD ± 0.13), ulnar 1.53 (SD ± 0.51), fibular 1.33 (SD ± 0.37), tibial 1.39 (SD ± 0.39), (2) internerve CSA-variability 1.76 (SD ± 0.37), (3) intraplexus CSA-variability 1.52 (SD ± 0.37), (4) side-to-side difference ratio of the CSA-variability: median 1.21 (SD ± 0.04), ulnar 1.2 (SD ± 0.25), fibular 1.19 (SD ± 0.23), tibial 1.28 (SD ± 0.24) and brachial plexus 1.19 (SD ± 0.23). CSA did not correlate with height in PN, but correlated with weight in the ulnar nerve [Guyon's canal, r = 0.411, p = 0.0237, elbow r = 0.409, p = 0.0248]. Significant changes between sex were found only in the ulnar (Guyon's canal, p = 0.0265), fibular (popliteal fossa, p = 0.0336) and sural nerve (p = 0.048). CSA decreased with age in the median (axilla, p = 0.0236), and radial nerve (spiral groove, p = 0.0037) and increased in the tibial nerve (ankle, p < 0.0001).
Conclusions:
The CSA reference values reported seem to correlate at certain sites with age, weight and sex but not with height.
Significance:
The new CSA variability measures may be helpful in investigating pathologies of the PN.
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