Morphological features of the inferior fascicle of the anterior inferior tibiofibular ligament.

In this study, the inferior fascicle of the anterior inferior tibiofibular ligament (AITFL) was classified to provide basic information to help elucidate the mechanism of ankle joint anterolateral impingement, and the morphological features of each type were compared for the purpose of clarification. This investigation examined 100 feet from 52 cadavers. The AITFL was classified into four types according to the presence or absence of the inferior fascicle and the positional relationship between the AITFL and the inferior fascicle of the AITFL. The morphological features of the AITFL that were measured included the fibre bundle length, fibre bundle width, fibre bundle angle, and the distance between the joint levels. A distinct, independent inferior fascicle of the AITFL was identified in 15 feet (15%). There were no significant differences in the morphological features based on differences in the AITFL classification. Therefore, these findings suggest that the presence or absence of the inferior fascicle and the difference in the positional relationship between the AITFL and the inferior fascicle of the AITFL are less likely to be involved in impingement during ankle dorsiflexion.