CarpalTunnel Syndrome – Adduction versus Abduction

Editor - Sansone et al¹ describe the findings of carpal tunnel syndrome in a recent article in Clinical Medicine & Research. In this article, the authors repeatedly describe weakness of thumb adduction as a sign of a carpal tunnel syndrome and cite the 2000 JAMA article by D’Arcy and McGee² as support of these statements; however, it is thumb abduction, by the abductor pollicis muscle, which is weak in carpal tunnel syndrome.² Weakness of thumb adduction is due to a problem of the adductor pollicis muscle, which is mainly innervated by the ulnar nerve. The typical sign of such an ulnar palsy is the Froment’s sign, named after the French physician, Jules Froment.