A Cadaveric Study of Metatarsal Length and Its Function in the Metatarsal Formula and Forefoot Pathology.

Background: The metatarsal parabola or formula is an important principle in assessing normal foot structure and pathology. To understand what effect the positions of the distal ends of the metatarsals have on foot function, the relative length of each metatarsal must be considered. The purpose of this study was to investigate what the normal metatarsal formula is and compare these findings with previous research.
Methods: Measurements of metatarsal lengths were taken from 20 feet of five male and five female cadavers. The mean lengths were used to identify each donor's metatarsal formula.
Results: On average, the most common formula presented was in the order of metatarsals II>III>IV>V>I.
Conclusions: These findings differ from historic measurements and raise questions regarding which metatarsal formula is considered normal. Further investigation is needed to standardize a more reliable method of measuring metatarsal lengths for evaluating foot biomechanics and planning forefoot surgeries.