New classification of the distal attachment of the fibularis brevis - Anatomical variations and potential clinical implications

Background: Although the lateral compartment of the leg is characterized by a high degree of morphological variation, very little information exists on the morphological variability of the fibularis brevis muscle (FBM) and fibularis digiti quinti (FDQ). The main aim of the study was to characterize the morphology of the FBM tendon and its accessory bands, to classify them and to determine the incidence of FDQ. The work attempts to determine the relationship between the types of the insertion of the FBM tendon and the occurrence of FDQ. Methods: Classical anatomical dissection was performed on 102 lower limbs fixed in 10% formalin solution. The morphology of the insertion of the FBM and of the FDQ was evaluated. Results: The FBM was present in all specimens. Two types of insertion were observed, the most common being Type I (70.6%): a single distal attachment in which the tendon inserts into the tuberosity at the base of the fifth metatarsal bone. The second most common was Type II (29.4%); this group was divided into three subtypes (A -C). The FDQ was present in 17.7% of specimens and always with Type I FBM. Conclusion: Both the FBM tendon and FDQ present significant morphological variation. Two main types of the FBM tendon determine the presence of the FDQ. Level of evidence: II Basic Science Research. (C) 2019 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.