Prevalence of the palmaris longus muscle and its relationship with grip and pinch strength: a study in a Turkish pediatric population.

Clinical studies generally reveal a trend of variation in the reported prevalence of the palmaris longus (PL) muscle absence. The aim of this study was to find an answer to the question of whether the congenital absence of tendon would affect hand functions or not. A total of 585 subjects, comprised of 305 males and 280 females, were included in our study. Mean age was 8.9 ± 1.4 standard deviation within a range of 6-11. For both sexes, the groups were divided further into three subgroups including 6-7, 8-9, and 10-11 years of age ranges. The grip strength of each hand and pinch strength of all fingers of each subject were measured separately. The absence of PL tendon in the right hand was 35.4 % in females, 25.9 % in males, and 30.4 % in overall average. The distribution of absence of the palmaris longus muscle between both genders was statistically significant. The p value for the right hand was 0.013. The absence of PL tendon in the left hand was 37.5 % in females, 27.9 % in males, and an overall average of 32.5 %. The p value for the left hand was 0.017. In terms of grip strength, a comparison between females and males did not reveal a significant difference. The pinch strength of the second fingers of both hands did not show any difference in both sexes. Pinch strength of the third finger of the right hand was different only in girls of subgroup 6-7 ages (p = 0.024). In girls, the pinch strength of the fourth finger of the right hand of subgroups 6-7 and 10-11 ages showed difference (p = 0.009 and p = 0.026, respectively). In boys, the fourth finger in subgroup of 8-9 ages showed significant difference in both hands (p = 0.011). The fifth fingers of both hands were found different in males for only subgroup of 8-9 ages (p = 0.001). Pinch strength of the fifth finger of the right hand was different in females for only subgroups of 6-7 and 10-11 ages (p = 0.023 and p = 0.047, respectively). While grip strength of the hand was not affected in the case of absence of the palmaris longus, in both sexes, pinch strength of the fourth and fifth fingers of both hands decreased.