Findings of the Anomalous Fibularis Digiti Quinti Muscle and Implications of its Associated Variable Presentations from Cadaver Dissections

Abstract

From our cohort (KSUCPM 2017) of 26 cadavers dissected by podiatric medical students for lower‐extremity anatomy, we observed bilateral and robust fibularis digiti quinti (FDQ) tendons in a 99‐year‐old female. Here, we describe the case, incidence of the FDQ tendons from dissections, and their variability as a component of anomalous lateral leg musculature. Due to variability, we have considerations for the anthropological and clinical significance of our findings. In both feet of our case, the FDQ tendon arose from the fibularis brevis tendon proximal to the lateral malleolus, but did not separate completely from the fibularis brevis tendon until passing through the inferior fibular retinaculum. On the lateral dorsum of the foot, the FDQ passed through a third fibular retinaculum formed by the fibularis tertius tendon, and inserted onto the extensor sling of the fifth digit. Our case is considered fully present FDQ. Of the 52 limbs dissected in the KSUCPM 2017 cohort, 17 limbs (33%) showed a fully present FDQ, 20 limbs (38%) exhibited an FDQ in a rudimentary form, and 15 limbs (29%) lacked an observable FDQ. Ongoing 2018 cadaver dissections are also represented. Functionally, human bipedality requires less dexterity than that of nonhuman primates in the routine use of hindlimbs. Therefore, we interpret the high variability of the FDQ, including its absence in many feet, as a relaxation of natural selection. The clinical significance of our findings suggests that the presence of a fully developed FDQ anomaly can be involved in pathology. In addition, physician awareness of the FDQ is important for surgical considerations.Support or Funding InformationResearch supported by Kent State University College of Podiatric Medicine.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.