Two fingerbreadths, one finger's width: on the proximity of the radial nerve to the deltoid tuberosity.

ABSTRACT

INTRODUCTION: The aim of this study was to find a convenient technique to evaluate the location of the radial nerve (RN) with reference to the deltoid tuberosity (DT). MATERIALS AND METHODS: Sixty-eight upper extremities, embalmed using a modified version of Thiel's method, were included in the study. The interval between the tip of the greater tubercle of the humerus and the distal tip of the lateral humeral epicondyle (LE) was defined as humeral length (HL). The most prominent point of the DT was used as the point of reference. Through this point, a horizontal reference line which met the humeral axis at the dorsal side of the humeral shaft was simulated. The longitudinal distance between the crossing point of the horizontal line and the humeral axis and the RN was measured (distance 1). The interval between the intersection point and the reference point at the DT was measured (distance 2). Data were evaluated in centimeters. RESULTS: For the whole sample, the HL averaged 31.0 cm (SD 2.3; range 26.2-36.9). Distance 1 averaged 2.2 cm (SD 0.3; range 1.6-3.1), and distance 2 averaged 1.2 cm (SD 1.0; range 0-2.8). The HL was larger in the male group when compared to females (p < 0.001; males mean 32.2 cm; females mean 29.5 cm). There was no difference regarding distance 2 (p = 0.59; males mean 1.2 cm; females mean 1.3 cm) between the sexes. Distance 1 was significantly (p = 0.02) larger in the male group (mean 2.3 cm) when compared to females (mean 2.1 cm). Concerning sides, there were no differences regarding all evaluated parameters (HL p = 0.6; Distance 1 p = 0.6; distance 2 p = 0.8). CONCLUSIONS: This study provides an easily applicable technique to localize the RN with reference to the DT.