Clinical Assessment of the Palmaris Longus – Accuracy of common tests

Abstract

Background : The Palmaris longus is a small vestigial muscle that is used as a tendon graft by surgeons. There are several tests described to detect the presence of the muscle clinically and there are variable opinions about which test is better. We set out to determine which of ten common tests brings out the tendon better. Methods : We conducted a prospective study and subjected all participants to 10 tests to detect the presence of the Palmaris Longus. A negative test on all tests was judged to mean absence of the tendon while a positive result on any test was judged to be positive. Participants provided written informed consent and assent was sought from the next of kin in the case of those aged below 18 years. The study was approved by the hospital ethics board and permission was granted by the school authorities. Results : The Standard test described by Schaeffer was the most accurate while the open hand sign described by Bhattacharya was the least accurate. Conclusion : Tests that incorporate wrist flexion, thumb abduction, opposition and finger flexion are best at bringing out the Palmaris tendon. Clinicians should be aware of this as they counsel patients who need tendon grafts. Studies aiming at detecting the presence of the Palmaris longus would be more accurate were they to use these tests