An accessory slip of the fibularis tertius to the extensor digitorum longus - an unreported variant.

The fibularis tertius (FT) is one of three muscles which constitute the anterior compartment of the leg. The anatomical variants of this muscle usually pertain to its origins, number of final tendons or points and shapes of insertions. In this case, it had an additional slip (AS) which originated from the same area as the main muscle belly and after descending along the extensor digitorum longus (EDL) it fused with one of its main tendons. The main muscle belly and its tendon, in its usual manner, reached the proximal dorsal surface of the fifth metatarsal bone. To our knowledge, no similar case had been described before. This case reveals that human anatomy, though it may be thoroughly described, can still be a surprise and a vast field for new discoveries. Knowledge about these variants is important from both the scientific and clinical points of view.