The prevalence of absence of the palmaris longus--a study in a Chinese population and a review of the literature.

Most standard textbooks of hand surgery quote the prevalence of absence of palmaris longus at around 15%. However, this figure varies considerably in reports from different ethnic groups. We studied 329 Chinese men and women and found palmaris longus to be absent unilaterally in 3.3%, and bilaterally in 1.2%, with an overall prevalence of absence of 4.6%. There was no significant difference in its absence with regard to the body side or the sex. Our literature review revealed a low prevalence of absence in Asian, Black and Native American populations and a much higher prevalence of absence in Caucasian populations. It is clear that a standard prevalence of absence of the palmaris longus cannot be applied to all populations.