Three Variations of the Dorsal Foot Musculature

Introduction: This case report documents a unilateral muscular variation observed in a detailed dissection of the right dorsal surface of the foot in one cadaver. This region involves the extensor digitorum longus, extensor digitorum brevis, extensor hallucis longus, extensor hallucis brevis, and the dorsal interossei muscles. Background: There have been some rare documented cases of extensor hallucis longus variations, as well as rare extensor digitorum longus variations in literature, but there have not been any documented cases matching the morphology noted here. Case Findings: During a detailed cadaveric dissection of a 91 year old female cadaver, the right dorsal surface of the foot revealed multiple variations in the muscular anatomy. The first variation involved an accessory extensor digitorum longus tendon. This accessory tendon traveled inferiorly to the second tendon and inserted at the proximal region of the third middle phalanx. The second variation involved an accessory first dorsal interossei originating at the second metatarsal and inserting at the first proximal phalanx. The third variation involved an accessory muscle belly of the extensor digitorum brevis. This belly was found distal to the remainder of the muscle, originating at the fibular retinaculum and inserting at the second middle phalanx. Conclusion: Due to the multiple anatomical variations found in the right foot, it may be possible that this subject had an issue with abnormal gait or foot pain. Atypical knowledge of different anatomical variants could also help improve diagnosis of foot tendonitis and myofascial pain, as well as outcomes of tendon transfer surgeries.