The frequency of absence of palmaris longus in a South African population of mixed race

The palmaris longus (PL) is a weak flexor of the wrist that may be harvested as a tendon graft and used in surgical procedures for reconstructive purposes. The PL is congenitally absent in 15% of the worldwide population. However, the frequency of absence varies considerably among different population groups, being as high as 63.9% in the Turkish population and as low as 3% in the black population in the Republic of Congo. In this study, South African persons of mixed race (n = 201) were assessed by two anatomists for the presence of the PL tendon using three clinical tests, namely the Traditional Test, Mishra's Test II, and the Gangata Test. The most reliable of the three tests used was determined using Kendall's coefficient of concordance. Of the total number of subjects used, 11.5% had absence (either bilaterally or unilaterally) of the PL tendon. There was a 5.5% bilateral absence of the PL. The study revealed that the PL tendon may present in six different patterns according to the clinical assessment tests applied, the presence or absence of the PL alongside the flexor capi radialis, and the degree of prominence of PL, if present. Using the Kendall's coefficient of concordance, the Mishra's Test II, and the Gangata Test, both involving abduction of the thumb, were found to be most effective in revealing the PL. The frequency of absence of the PL in South Africans of mixed race has been determined.