Ulnar nerve measurements in healthy individuals to obtain reference values

Abstract

The aim of this study was to obtain the ultrasonographical reference values of ulnar nerve cross-sectional areas at the common areas of nerve entrapment as well as any differences related to age, sex, weight, height, dominant arm. Cross-sectional areas of the ulnar nerves of 72 healthy volunteers were measured bilaterally at the level of the epicondyle, 2 cm proximal to and 2 cm distal to the epicondyle, just at the entrance of cubital tunnel, at arterial split, at Guyon's canal. Age, sex, body weight, height, body mass index, and dominant extremity were recorded. The mean ulnar nerve cross-sectional area was 5.8 ± 1.1 mm(2) at 2 cm proximal to medial epicondyle, 6.2 ± 1.1 mm(2) at the medial epicondyle, 5.6 ± 0.9 mm(2) at the entrance of the cubital tunnel, 5.6 ± 1.0 mm(2) at 2 cm distal to medial epicondyle (inside the flexor carpi ulnaris), 5.0 ± 0.6 mm(2) at arterial split, and 4.9 ± 0.6 mm(2) at Guyon's canal. There was statistically no difference between the dominant and nondominant sides (p > 0.05). Females had statistically smaller nerves than males (p < 0.05). There was a significant correlation with height at all levels; also, weight was significantly correlated with cross-sectional areas except at two levels: tip of medial epicondyle and 2 cm distal. This study provides normative data of ulnar nerve ultrasonography and as well as any differences related to age, sex, height, weight, and dominant arm.