Fibularis tertius
muscle
In human anatomy, the fibularis tertius (historically known as the peroneus tertius) is a muscle in the anterior compartment of the leg. It acts to tilt the sole of the foot away from the midline of the body (eversion) and to pull the foot upward toward the body (dorsiflexion).
Structure
The fibularis tertius arises from the lower third of the front surface of the fibula, the lower part of the interosseous membrane, and septum, or connective tissue, between it and the fibularis brevis. The septum is sometimes called the intermuscular septum of Otto.
The muscle passes downward and ends in a tendon that passes under the superior extensor retinaculum and the inferior extensor retinaculum of the foot in the same canal as the extensor digitorum longus muscle. It may be mistaken as a fifth tendon of the extensor digitorum longus. The tendon inserts into the dorsal (superior) surface of the base of the fifth metatarsal bone.
The fibularis tertius is supplied by the deep fibular nerve. In rare cases, it may also be supplied by the common fibular nerve. This is unlike the other fibularis muscles, which are located in the lateral compartment of the leg and are supplied by the superficial fibular nerve, since the fibularis tertius is found in the anterior compartment of the leg.
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This entry incorporates text from “Fibularis tertius” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.