Fibularis tertius (left) (Musculus fibularis tertius)
Educational content only — not medical advice.
Anatomy
A small slip split from extensor digitorum longus, its tendon inserting dorsally on the fifth metatarsal base — an almost uniquely human muscle, absent in 5–17% of people.
Origin & insertion
Distal third of the fibular shaft and interosseous membrane.
Action
Dorsiflexes with eversion — the modern oblique human gait movement.
Innervation
Deep peroneal nerve (L5–S1).
Clinical notes
Its avulsion with the fifth metatarsal base is the classic avulsion fracture; its absence causes no deficit — a pure anatomical variant.
Related structures
Educational references
FAQ
What is the role of the Fibularis tertius (left)?
A small slip split from extensor digitorum longus, its tendon inserting dorsally on the fifth metatarsal base — an almost uniquely human muscle, absent in 5–17% of people.
Why is the Fibularis tertius (left) clinically important?
Its avulsion with the fifth metatarsal base is the classic avulsion fracture; its absence causes no deficit — a pure anatomical variant.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details