Prevalence of the Palmaris Longus Muscle in Indian American Population through Clinical Evaluation

SUMMARY
Background. The variability in the prevalence of Palmaris longus (PL) agenesis has been well-documented in various ethnic groups and populations. Lamentably, there is no previous study in the literature has reported the prevalence of PL agenesis in the Indian American population. This study aimed to determine the prevalence of PL agenesis and its association with gender, body side and hand dominance in the Indian American population.
Methods. In this cross-sectional study, a total of 600 subjects (300 males and 300 females) belonging to 18-45 years were accessed for the presence or absence of PL tendon, using a series of clinical tests. The association between the prevalence of PL agenesis and gender, limb laterality and hand dominance were determined by the Chi-square test. Overall agenesis of PL reached 15.33%, and unilateral agenesis (8%) was more common than bilateral absence (7.33%).
Results. The PL agenesis was found lesser (p = 0.037) in females (14.33%) than the males (16.33%). The PL agenesis was significantly more often on the left side than the right (p = 0.02). In right-hand dominant subjects, the left-sided agenesis was significantly more common (p = 0.014) and in left-hand dominant subjects, the right-sided agenesis was greater (p > 0.05).
Conclusions. Palmaris longus tendon agenesis in Indian American subjects was more analogous to the standard textbooks of hand surgery, but much higher than the other Asian and African populations. This comparison confirms that the prevalence of PL is race-dependent. The present study data may be valuable for tissue banks for harvesting the PL tendon allografts from Indian Americans which could be useful for surgeons during various reconstructive and tendon grafting surgery in Indian American patients.