Anomalous origin of the thenar motor branch encountered during carpal tunnel release.

Abstract

Background: This illustrative case demonstrates the thenar motor branch (TMB) arising from the median nerve proper through the palmaris fascia, visualized during a carpal tunnel release procedure.

Case description: A 64-year-old with a history of hypertension and diabetes presents to the clinic with 1 year of neck pain, upper extremity numbness and tingling, wasting of hand muscles, and weakness of the left hand. Electromyography confirmed cubital tunnel syndrome bilaterally and right carpal tunnel syndrome. The patient underwent right cubital and carpal tunnel decompressions.

Conclusion: Awareness of TMB anomalies and careful identification during surgery can prevent iatrogenic injury and further complications.