RESUMO
OBJECTIVE: The purpose of this study is to investigate the incidence and ratio of biphalangeal toes in Korean adult and to investigate whether this finding correlates with the evolution of human toes. METHOD: The materials used in this study consisted of 1,290 radiographs of the human feet obtained from 645 adults with foot symptom and complete osseous growth. The 1,290 radiographs consisted of anteroposterior weightbearing radiographs and nonweightbearing oblique radiographs. Those were retrospectively reviewed and carried out of detailed macroscopic examinations. RESULTS: Biphalangeal toe was observed for the 5th toe in 934 cases (72.40%), for the 4th toe in 161 cases (12.48%), for the 3rd toe in 7 cases (0.54%), and for the 2nd toe in 1 case (0.08%). Bilaterality of biphalangeal and triphalangeal toes for each toe was observed over 97.1%. CONCLUSION: Our results are in agreement with Nakashima and it is likely that over 70% of the Asian population have only two phalanges in their fifth toes, and it seems to be an example of microevolution or genetic adaptation to bipedalism.