Anatomical Correlation between Ulnar Neuropathy and Triceps in Electrodiagnostic Studies

Introduction: Nerve conduction studies (NCV) and electromyography (EMG) are key diagnostic tools for identifying mononeuropathy and radiculopathy. Triceps denervation has traditionally been attributed to C7 radiculopathy or radial neuropathy. However, recent studies suggest possible ulnar innervation of the triceps muscle, introducing ambiguity in interpreting EMG findings, particularly in patients with ulnar neuropathy. We aimed to evaluate the prevalence of tricep denervation in patients with and without ulnar neuropathy. Methods: This case-control study included patients who underwent EMG at the Progressive Neurology and Sleep Center between January and August 2024. Data were analyzed using STATA software. The prevalence of triceps denervation changes was compared between patients with and without ulnar neuropathy using chi-square tests and logistic regression. Results: The study included 295 patients: 146 with ulnar neuropathy and 149 without. Triceps denervation was present in 41 patients (28%) with ulnar neuropathy and in 46 patients (31%) without ulnar neuropathy. Prevalence was not significantly different between the groups. Logistic regression showed an odds ratio of 0.42 ± 3.51 (p = 0.3) for triceps denervation in patients with ulnar neuropathy after adjusting for confounding factors. Conclusion: Difference in the prevalence of triceps denervation between patients with and without ulnar neuropathy was not significant. These findings support the current interpretation of triceps denervation patterns in EMG studies.