Different frequency of the absence of the palmaris longus according to assessment methods in a Korean population

The palmaris longus (PL) is a slender, spindle-shaped weak flexor of the wrist. Congenital absence of the PL is estimated to occur in 15% among individuals worldwide. However, the frequency of its absence varies considerably among different population groups and with different detection techniques. In the present study, the presence of the PL tendon was examined in a Korean population (n=269) using three clinical tests, namely the Traditional Test, Mishra's Test II, and the Gangata Test. We classified subjects into six types based on whether inspection or palpation was required to determine the presence of the PL and flexor carpi radialis. The most reliable test was determined using Kendall's coefficient of concordance. Our results showed that the PL tendon was absent in 4.1% of the subjects in our study, and bilateral and unilateral absences were 2.2% and 1.8%, respectively. Statistical analysis revealed that these tests had similar reliability for assessing the PL tendon, and the Traditional Test showed the highest effectiveness, at 93%. Therefore the Traditional Test was found to be the most effective for revealing the PL in this Korean population.