Work

Anconeus Epitrochlearis-Induced Cubital Tunnel Syndrome: A Rare Case Report

Year: 2026

Type: article

Abstract: Cubital tunnel syndrome (CTS) is the second most common compression neuropathy of the upper limb.While most cases result from compression beneath Osborne's ligament or between the heads of the flexor carpi ulnaris, rare anatomical variations such as the anconeus epitrochlearis muscle (AEM) may also cause ulnar nerve entrapment.We report the case of a 40-year-old right-hand-dominant male presenting with progressive numbness and paresthesia along the ulnar aspect of the right forearm and into the fourth and fifth digits, accompanied by medial elbow pain.Clinical examination revealed a positive Tinel's sign over the cubital tunnel and symptom reproduction with sustained elbow flexion.Electromyography demonstrated severe focal slowing of ulnar nerve conduction at the elbow.Magnetic resonance imaging identified an accessory AEM compressing the ulnar nerve.Surgical decompression with resection of the accessory muscle was performed without ulnar nerve transposition.The patient experienced immediate postoperative symptom relief and remained asymptomatic at the six-month follow-up.Although uncommon, the AEM should be considered a potential cause of CTS, particularly in patients with atypical or refractory symptoms.MRI plays a crucial role in diagnosis, and surgical decompression provides reliable symptom resolution with excellent outcomes.

Source: Cureus

DOI: 10.7759/cureus.118874