Topography of the deep branch of the ulnar nerve between genders: a cadaveric study with potential clinical implications

Abstract

Abstract The lack of meticulous knowledge concerning the topographical anatomy of the deep branch of the ulnar nerve (DUN) may pose difficulties, leading to a delay or a misdiagnosis of a DUN injury. Identification of the DUN is quite difficult without precise anatomical landmarks as reference points. The current study investigates the topography of the DUN between genders, taking as a reference point a well-known landmark, the Kaplan line, used in hand surgery for carpal tunnel release. Twenty-two (15 males and 7 female) fresh frozen adult cadaveric hands were dissected by using magnifying loupes (3.5 and 5.0 x). We marked values proximal to the Kaplan line as positive (+), while we marked distal ones as negative (-). The mean distance DUN–Kaplan line was 1.69 ± 4.45 mm. In male hands, the mean distance was 4.17 ± 1.88 mm, distal to the Kaplan line, while in females, the mean distance was −4.92 ± 0.69 mm proximal to the Kaplan line. Gender dimorphism was detected, with higher statistically significant values in male hands (p = 0.001). Cadaveric studies of the DUN topography, course, and distribution pattern are uncommon. The current study provides an accurate description of the DUN topography, taking the Kaplan line as a reference point, emphasizing gender differences. The DUN is located distally in males and proximally in females. Knowledge of these predictable anatomical relations may help hand surgeons intraoperatively when dealing with a DUN lesion, because of hand trauma or during the decompression of the DUN.