Prevalence of Absence of Palmaris Longus Tendon in a Population Sample from a Multiethnic Brazilian City.

Objective  The objective of the study was to determine the prevalence of absence of palmaris longus tendon in a population sample from a multiethnic Brazilian city. Methods  A cross-sectional observational study was carried out between October 2017 and April 2018. We included male and female volunteers aged 18 years or older. The absence of palmaris longus tendon was determined by asking the volunteers to perform the Schaeffer test bilaterally. Results  We prospectively collected data on 1,008 volunteers, 531 male and 477 female, with age between 18 and 74 years (mean 38.4 years). The absence of palmaris longus tendon was observed in 264 (26.2%) volunteers. Bilateral absence was detected in 123 volunteers (12.2%), 60 female (48.8%) and 63 male (51.2%). Unilateral absence was found in 141 patients (14.0%), 54 female (38.2%) and 87 male (61.8%) ( p  < 0.05). Conclusion  The prevalence of absence of palmaris longus tendon in our study was 26.2%. There was no statistically significant difference between gender and bilaterally. The absence of palmaris longus tendon was predominant on unilateral right side in males.