Ultrasonographical and histological cross-sectional study of the human superficial branch of the radial nerve

Purpose: The superficial branch of radial nerve (SBRN) is one of the cutaneous neves biopsied for diagnosis of peripheral neuropathy. The purpose of this study is to find out the cross sectional microanatomy of the (SBRN) at antecubital fossa for changes in the fascicular, non-fascicular components with respect to age and also to find cross sectional area of SBRN in healthy volunteers. Materials and Methods: Sixty SBRN were harvested bilaterally from 30 fresh human bodies (25 males and five females) with ages of 37 to 88 years. Samples were divided into three age groups (G1, 37-55 years; G2, 55-70 years; G3, ≥71 years) and studied at different magnifications after histological processing for morphometric analysis - total cross-sectional (Asc), fascicular (Af), and non-fascicular area (Anonf). Fifteen volunteers SBRN cross sectional area was measured by ultrasonography (US). Results: The SBRN was found to have 2-6 fascicles. The differences in the adipose tissue (FAT) areas, between G1 and G2 (p=0.233) and between G2 and G3 (p=0.458) were not statistically significant. However, a significant difference was seen between G3 and G1 (p=0.021). The differences in the non-adipose tissue (FAT) areas, between G1 and G2 (p=0.110), between G2 and G3 (p=0.950) and between G3 and G1 (p=0.210) were not statistically significant. The amount of adipose tissue (FAT) in the epifascicular and interfascicular region increased in elderly individuals (age ≥71 years). Ultrasonographic cross-sectional area ranged from 2 to 3 mm². Conclusions: Our study revealed comparatively more adipose tissue in human SBRN with advanced age (≥71 years). Findings may help to explain poor prognosis with advancing age following repair. SBRN ultrasonographical Asc was comparable to histological Asc in ages between 37-55 years.