Prevalence of palmaris longus absence--a study in the Yoruba population

Palmaris longus (PL) has received a growing interest for its role in constructive surgery. Since the agenesis of PL shows a strong racial variation, it is conceivable that its prevalence on the Yoruba ethnic population in Nigeria will further confirm this phenomenon. A total of 600 subjects comprising 335 males and 265 females aged 8-60 years were used to assess the prevalence of agenesis of the PL in Yoruba tribe. The overall prevalence of absence both unilaterally and bilaterally in the two sexes was 6.7%. In males, unilateral absence was 5.4%. The distribution on the right and left were 2.4% and 3.0% respectively. The bilateral absence was 1.5%. In females, unilateral absence was 6.0%. The distribution on the right and left were 2.6% and 3.4% respectively. Bilaterally, it was 0.4%. In one subject unilaterally, PL was observed to have differentiated from flexor carpi radialis. Results of this finding suggested that the prevalence of PL agenesis as reported in standard anatomy texts is significantly different from our observation in this Yoruba population. The differentiation of PL tendon from flexor carpi radialis is indicative that both muscles may develop from the same muscle group as previously suggested.