Prevalence of Palmaris Longus Agenesis in a Hospital in Iran

The prevalence of the palmaris longus agenesis (PLA) has been variously reported to be from 1.5% to 64% in different ethnic groups. Lack of reliable information about the state of the PLA in Iran made us to design a study on the agenesis of the palmaris longus (PL) among Iranian population during 2009. One thousand participants were included in this descriptive study. Subjects were patients and personnel of a sample of a major orthopedic surgery center in Iran. The Schaeffer test was used to detect the presence or absence of the PL. An orthopedic resident conducted the test (observer reliability 98%). The prevalence of agenesis was determined in the sample and its actual prevalence was estimated for the whole population. The role of gender and handedness was also considered in the presence or absence of the PLA. The prevalence of the PLA was estimated to be 22.8%; 10.2% agenesis on the right side, 5.9% on the left side, and 6.7% bilateral PLA. The relationship between PLA and gender didn’t appear to be significant. Among people with PLA 43% and among people without PLA 17% were left handed (P < 0.05, odds ratio [OR]: 3.7). The prevalence of the PLA in Iranians seems to be comparable with the average Caucasian values which is estimated to be 22.4%. Furthermore, significant relationship exists between the PLA and left hand dominance.