Hypertrophic ancenous epitrochlearis muscle as a cause of ulnar neuropathy at elbow.

We report herein a 35-year-old man who suffered from pain at his left elbow and numbness in his left hand. Electromyographic studies demonstrated a localized nerve conduction block in the left elbow region. Ultrasonographic evaluation revealed enlargement of the ulnar nerve at the level of the medial epicondyle as well as bilateral anconeus epitrochlearis muscles, one of which was hypertrophic, causing the ulnar neuropathy at the symptomatic site. We emphasize with this case report the complementary role of ultrasound in peripheral nerve pathologies, as it confirmed the entrapment and determined the underlying cause.