The Flexor Digitorum Accessorius Longus—A Cadaveric Study

Flexor digitorum accessorius longus is an anatomical variant that has previously been shown to be associated with a variety of pathological conditions localized to the posteromedial aspect of the ankle and hindfoot. In particular, this anomalous muscle has been reported to be the cause of tarsal tunnel syndrome. Despite recognition of this muscular anomaly as a cause of foot and ankle pathology, the origin, course, and insertion of flexor digitorum accessorius longus has not been thoroughly illustrated in the anatomical literature. In an effort to accurately detail the anatomy of the flexor digitorum accessorius longus, we undertook a cadaveric dissection and prepared a photographic study of this anomalous skeletal muscle. Level of Clinical Evidence: 5.