Ultrasonographic reference values for the deep branch of the radial nerve at the arcade of Frohse

Purpose The deep branch of the radial nerve (DBRN) enters the forearm as it passes under the arcade of Frohse. This is the most common entrapment site of the DBRN in the forearm. In this study, we investigated the ultrasonographic reference values for the diameters and cross-sectional area (CSA) of the DBRN at the level of the arcade of Frohse in a healthy sample of the population. Methods Sixty-five healthy Caucasian volunteers (130 nerves) were recruited for this study. The reference range [mean ± 2 standard deviations (SD); 2.5th–97.5th quintiles] and the upper limit of the side-to-side difference were determined. The effects of age, gender, handedness, height, and body mass index were examined. Results The mean age was 41.8 ± 11.2 years (range 18–75 years). The mean ± 2SD of the CSA was 0.50–1.42 mm 2 . The upper limit of the normal side-to-side difference was 0.35 mm 2 . The differences between males and females and between the dominant and non-dominant arms were not significant. The mean anteroposterior and transverse diameters were 0.83 ± 0.13 and 1.23 ± 0.29 mm, respectively. A significant correlation between the dominant-side CSA and age ( r = 0.41; p