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.