In human anatomy, the fibularis brevis (or peroneus brevis) is a muscle that lies underneath the fibularis longus within the lateral compartment of the leg. It acts to tilt the sole of the foot away from the midline of the body (eversion) and to extend the foot downward away from the body at the ankle (plantar flexion).

Structure

1123 Muscles of the Leg that Move the Foot and Toes c

The fibularis brevis arises from the lower two-thirds of the lateral, or outward, surface of the fibula (inward in relation to the fibularis longus) and from the

connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...

between it and the muscles on the front and back of the leg. The muscle passes downward and ends in a tendon that runs behind the lateral malleolus of the ankle in a groove that it shares with the tendon of the fibularis longus; the groove is converted into a canal by the superior fibular retinaculum, and the tendons in it are contained in a common mucous sheath. The tendon then runs forward along the lateral side of the

calcaneus In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. S ...

, above the

calcaneal tubercle In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. ...

and the tendon of the fibularis longus. It inserts into the tuberosity at the base of the fifth metatarsal on its lateral side. The fibularis brevis is supplied by the superficial fibular (peroneal) nerve.

Function

The fibularis brevis is the strongest abductor of the

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...

. Together with the fibularis longus and the tibialis posterior, it extends the foot downward away from the body at the ankle (plantar flexion). It opposes the tibialis anterior and the fibularis tertius, which pull the foot upward toward the body ( dorsiflexion).'' Gray's Anatomy (1918), see infobox'' The fibularis longus also tilts the sole of the foot away from the midline of the body (

eversion Eversion (from the verb "evert") is the process of turning inside-out. Eversion may refer to: * Eversion (kinesiology), the anatomical term of motion denoting the movement of the sole of the foot away from the median plane * ''Eversion'' (video g ...

). Together, the fibularis muscles help to steady the leg upon the foot, especially in standing on one leg.

Clinical significance

When the base of the fifth metatarsal is fractured, the fibularis brevis may pull on and displace the upper fragment (known as a Jones fracture). An inversion sprain of the foot may pull the tendon such that it avulses the tuberosity at the base of the fifth metatarsal.

Nomenclature and etymology

Terminologia Anatomica ''Terminologia Anatomica'' is the international standard for human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology, a program of the International Federation of Associations of Anatomis ...

'' designates "fibularis" as the preferred word over "peroneus.". The word "peroneus" comes from the Greek word "perone," meaning pin of a brooch or a buckle. In medical terminology, the word refers to being of or relating to the fibula or to the outer portion of the leg.

Additional images

File:Gray357.png, Coronal section through right ankle and

subtalar joint In human anatomy, the subtalar joint, also known as the talocalcaneal joint, is a joint of the foot. It occurs at the meeting point of the talus and the calcaneus. The joint is classed structurally as a synovial joint, and functionally as a pla ...

s. (Label for Peroneus brevis is at right, third from the bottom.) Image:Gray258.png, Bones of the right leg, anterior surface. Image:Gray268.png, Bones of the right foot, dorsal surface. Image:Gray437.png, Muscles of the front of the leg. Image:Gray440 color.png, Cross-section through middle of leg. Image:Gray551.png, The popliteal, posterior tibial, and fibular arteries. Image:Gray1239.png, Back of left lower extremity. File:Slide16wwww.JPG, Fibularis brevis muscle File:Slide1ABBBA.JPG, Muscles of the sole of the foot. File:Slide1Bebe.JPG, Dorsum of Foot, deep dissection. File:Slide2xzxz.JPG, Muscles of leg, lateral view, deep dissection.

References

External links

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PTCentral
{{Authority control Muscles of the lower limb