Double origin of the extensor hallucis longus muscle: a case report.

Most of the anatomic variations of the extensor hallucis longus (EHL) muscle are related to the tendon of insertion. We show a double origin of the EHL from the medial aspect of the fibula and the lateral aspect of the tibia. A 27-year-old male with a double closed fracture of tibia and fibula showed an involuntary extension of the big toe during foot plantar flexion after surgery. A tendon fibrosis by the fixation plates could be the cause of the foot functional alteration. Interestingly, the anatomic variation described could be related to the postsurgical foot dysfunction, since when the fibrotic tissue was removed the normal extension of big toe recovered. As illustrated in this case report, knowledge of anatomic variations is very useful, particularly in the context of foot surgery.