Fibula

For the ancient jewelry type, see Fibula (brooch).
Fibula

Position of fibula in human (shown in red)

Cross section of human lower leg, showing fibula in centre (latin terminology)
Details
Latin (os) fibula
Articulations Superior and inferior tibiofibular joint
Identifiers
Gray's p.260
MeSH A02.835.232.043.650.321
TA A02.5.07.001
FMA 24479
Anatomical terms of bone

The fibula (/ˈfɪbjʉlə/[1][2]) or calf bone is a leg bone located on the lateral side of the tibia, with which it is connected above and below. It is the smaller of the two bones, and, in proportion to its length, the slenderest of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below the level of the knee joint, and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia, and forms the lateral part of the ankle joint.

Structure

The bone has the following components:

Blood supply

The blood supply is important for planning free tissue transfer because the fibula is commonly used to reconstruct the mandible. The shaft is supplied in its middle third by a large nutrient vessel from the fibular artery. It is also perfused from its periosteum which receives many small branches from the fibular artery. The proximal head and the epiphysis are supplied by a branch of the anterior tibial artery. In harvesting the bone the middle third is always taken and the ends preserved (4 cm proximally and 6 cm distally)

Development

The fibula is ossified from three centers, one for the shaft, and one for either end. Ossification begins in the body about the eighth week of fetal life, and extends toward the extremities. At birth the ends are cartilaginous.

Ossification commences in the lower end in the second year, and in the upper about the fourth year. The lower epiphysis, the first to ossify, unites with the body about the twentieth year; the upper epiphysis joins about the twenty-fifth year.

Function

The fibula does not carry any significant load (weight) of the body. It extends past the lower end of the tibia and forms the outer part of the ankle providing stability to this joint. It has grooves for certain ligaments which gives them leverage and multiplies the muscle force. It provides attachment points for the following muscles:

Muscle attachments (seen from the front)
Muscle attachments (seen from the back)
Muscle Direction Attachment[3]
Biceps femoris muscle Insertion Head of fibula
Extensor hallucis longus muscle Origin Medial side of fibula
Extensor digitorum longus muscle Origin Proximal part of the medial side of fibulua
Fibularis tertius Origin Distal part of the medial side of fibulua
Fibularis longus Origin Head and the lateral side of fibula
Fibularis brevis Origin Distal 2/3 of the lateral side of fibula
Soleus muscle Origin Proximal 1/3 of the posterior side of fibula
Tibialis posterior muscle Origin Lateral part of the posterior side of fibula
Flexor hallucis longus muscle Origin Posterior side of fibula

Clinical significance

Avulsion fracture

An avulsion fracture of the head of the fibula refers to the fracture of the fibular head because of a sudden contraction of the biceps femoris muscle that pulls its site of attachment on the bone. The attachment of the biceps femoris tendon on the fibular head is closely related to the lateral collateral ligament of the knee. Therefore, this ligament is prone to injury in this type of avulsion fracture.[4]

History

Etymology

The word fibula can be dated back to c. 1670 to describe a clasp or brooch – see fibula (brooch) – and was first used in English for the smaller bone in the lower leg c. 1706. It derives from Latin fībula, also meaning a clasp or brooch. The bone was so called because it resembles a clasp like a modern safety pin.[5]

In other animals

Because the fibula bears relatively little weight in comparison with the tibia, it is typically narrower in all but the most primitive tetrapods. In many animals, it still articulates with the posterior part of the lower extremity of the femur, but this feature is frequently lost (as it is in humans). In some animals, the reduction of the fibula has proceeded even further than it has in humans, with the loss of the tarsal articulation, and, in extreme cases (such as the horse), partial fusion with the tibia.[6]

See also

This article uses anatomical terminology; for an overview, see anatomical terminology.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

  1. ↑ OED 2nd edition, 1989.
  2. ↑ Entry "fibula" in Merriam-Webster Online Dictionary.
  3. ↑ Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001). Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). pp. 364–367. ISBN 978-87-628-0307-7.
  4. ↑ Gottsegen, CJ; Eyer, BA; White, EA; Learch, TJ; Forrester, D (2008). "Avulsion fractures of the knee: imaging findings and clinical significance.". Radiographics 28 (6): 1755–1770. doi:10.1148/rg.286085503. PMID 18936034.
  5. ↑ etymonline.com
  6. ↑ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 205. ISBN 0-03-910284-X.

Additional Images

External links

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