The clinical significance of the palmaris longus tendon and functional superficial flexor of the little finger in the pathophysiology of carpal tunnel syndrome

Background: The pathophysiology of carpal tunnel syndrome is associated with increased intracarpal canal pressure. Recently, palmaris longus has been introduced as an independent risk factor for the development of carpal tunnel syndrome. The purpose of this study was to assess the association of carpal tunnel syndrome with the presence of palmaris longus tendon and functional superficial flexor of the fifth finger. Methods: Fifty-four patients with severe and bilateral carpal tunnel syndromes that had indications for carpal tunnel release, and underwent surgery, were enrolled prospectively in this study. Seventy patients as control group were selected on a basis of age, gender, occupation, diabetes mellitus, thyroid disease, and rheumatoid arthritis. The presence or absence of the palmaris longus tendon and functional superficial flexor tendon to the little finger were assessed in both groups clinically. Results: The prevalence of palmaris longus agenesis was significantly lower in the carpal tunnel group but there was no association between carpal tunnel syndrome and presence of functional superficial flexor to the little finger. Conclusion: The presence of the palmaris longus tendon is associated with the development of carpal tunnel syndrome.