Clinical relevance of palmaris longus agenesis: common anatomical aberration

Abstract

Palmaris longus muscle, although of little functional use to the human upper limb, assumes great importance when used as a donor tendon for transfer or transplant. The variability in the prevalence of palmaris longus agenesis among various ethnic groups has been established, and the surgeon's awareness of the prevalence in a population or ethnic group is desirable. The prevalence of palmaris longus agenesis has, to the best of the authors' knowledge, not been reported in Indian patients. Five hundred Indian patients were examined for the presence or absence of palmaris longus tendon, using the conventional test for presence of palmaris longus. The prevalence and pattern of palmaris longus agenesis was analyzed statistically and any difference in prevalence or pattern of palmaris longus agenesis with regard to body side or sex was looked for. All statistical analysis was done using SPSS (version 12). chi2 test was used to analyze the association of agenesis with limb laterality and sex. The prevalence of palmaris longus agenesis was found to be 17.2% (8% bilateral and 9.2% unilateral). The prevalence of agenesis was significantly more common on the left side. Male subjects had a greater likelihood of unilateral agenesis, while female subjects were more likely to have bilateral agenesis. That prevalence of palmaris longus agenesis is race dependent is reaffirmed in the present study. Although the prevalence of palmaris longus agenesis in Indian patients was found to be much higher than the reported average prevalence in an Asian population, this tendon can still be counted on by surgeons treating Indian patients for use as a donor tendon, which will be present in a vast majority of Indian patients.