Incidence of Palmaris Longus Agenesis in the Young Iranian Population

Background: Palmaris longus (PL) is the most variable muscle in the body. The variation includes unilateral or bilateral agenesis, duplication or Y-shaped tendon‎. Methods: A total of 480 students within the age range of 18 to 23 years from Tehran medical institutions were ‎randomly selected for the current study‎‎. The Thompson test was used to support the Schaeffer test. Results: PL muscle was absent bilaterally in 23% and unilaterally in 28.5% of the subjects with the distribution of 16.9% on ‎the left and 11.6% on the right hands. In females, the bilateral absence was observed in 34.16%, while 18.7% ‎had unilateral absence with the distribution of 5.8% on the left and 12.9% on the right. Conclusions: It is believed that palmaris longus muscle is progressively disappearing in Iranian young people and ‎could prove a degenerative trend in the Iranian population.