Absence of the palmaris longus tendon in Indian population

BACKGROUND: Ethnic variations in the prevalence of the absence of the palmaris longus (PL) tendon are well known. Studies have also attempted to correlate its absence with other anatomical anomalies. However, most studies have been done in Caucasian populations. The present study was undertaken to know the occurrence of absence of palmaris longus in Indian population. MATERIALS AND METHODS: The presence of the PL tendon was clinically determined in 385 normal Indian men and women using the standard technique. In subjects with an absent PL tendon, three other tests were performed to confirm its absence. All subjects were also examined for the presence of the flexor digitorum superficialis (FDS) in the little finger. RESULTS: The overall unilateral absence of the tendon was 16.9% and the bilateral absence was in 3.3% in our population. There was no significant difference in its absence with regard to the body side or sex. The overall prevalence of the weak FDS in the little finger irrespective of the presence or absence of the PL tendon in our study was 16.10%. If we compare the deficiency of the FDS in the little finger with the absence of the PL tendon, the overall incidence is 4.15% and is statistically significant, while the sexwise distribution of the weak FDS with absent PL tendon was statistically significant in males and in females it was statistically insignificant. CONCLUSIONS: The prevalence of the unilateral absence of the PL tendon in an Indian population is comparable to the western population but a bilateral absence is significantly less. In patients with an absent PL tendon, the FDS of the little finger is weak, especially in males.