Ankle

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Ankle
Ankle en.svg
Lateral view of the human ankle
Latinarticulatio talocruralis
Gray'ssubject #95 349
MeSHAnkle+joint
 
  (Redirected from Ankle bone)
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Ankle
Ankle en.svg
Lateral view of the human ankle
Latinarticulatio talocruralis
Gray'ssubject #95 349
MeSHAnkle+joint

The ankle, or talocrural region,[1] is the region where the foot and the leg meet.[2] The ankle incudes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the Inferior tibiofibular joint.[3][4][5] In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" (without qualifiers) can refer broadly to the region or specifically to the talocrural joint.[1][2]

The main bones of the ankle region are the talus (in the foot), and the tibia and fibula (in the leg). The talus is also called the ankle bone.[6] The talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus.[7] The articulation between the tibia and the talus bears more weight than between the smaller fibula and the talus.

Contents

Name derivation

The word ankle or ancle is common, in various forms, to Germanic languages, probably connected in origin with the Latin "angulus", or Greek "αγκυλος", meaning bent.

Evolution

It has been suggested that dexterous control of toes has been lost in favour of a more precise voluntary control of the ankle joint.[8]

Anatomy

Bones

The boney architecture of the ankle consists of three bones: the tibia, the fibula, and the talus. The articular surface of the tibia is referred to as the plafond. The medial malleolus is a boney process extending distally off the medial tibia. The distal-most aspect of the fibula is called the lateral malleolus. Together, the malleoli, along with their supporting ligaments, stabilize the talus underneath the tibia.

The boney arch formed by the tibial plafond and the two malleoli is referred to as the ankle "mortise" (or talar mortise). The mortise is a rectangular socket.[6] The ankle is composed of three joints: the talocural joint (also called tibiotalar joint, talar mortise, talar joint), the subtalar joint (also called talocalcaneal), and the Inferior tibiofibular joint.[3][4][5] The joint surface of all bones in the ankle are covered with articular cartilage.

Ligaments

The ankle joint is bound by the strong deltoid ligament and three lateral ligaments: the anterior talofibular ligament, the posterior talofibular ligament, and the calcaneofibular ligament.

Though it does not span across the ankle joint itself, the syndesmotic ligament makes an important contribution to the stability of the ankle. This ligament spans the syndesmosis, which is the term for the articulation between the medial aspect of the distal fibula and the lateral aspect of the distal tibia. An isolated injury to this ligament is often called a high ankle sprain.

The boney architecture of the ankle joint is most stable in dorsiflexion. Thus, a sprained ankle is more likely to occur when the ankle is plantar-flexed, as ligamentous support is more important in this position. The classic ankle sprain involves the anterior talofibular ligament (ATFL), which is also the most commonly-injured ligament during inversion sprains. Another ligament that can be injured in a severe ankle sprain is the calcaneofibular ligament.

Disorders

Fractures

Symptoms of an ankle fracture can be similar to those of ankle sprains (pain), though typically they are often more severe by comparison. It is exceedingly rare for the ankle joint to dislocate in the presence of ligamentous injury alone.

The talus is most commonly fractured by two methods. The first is hyperdorsiflexion, where the neck of the talus is forced against the tibia and fractures. The second is jumping from a height - the body is fractured as the talus transmits the force from the foot to the lower limb bones.[9]

In the setting of an ankle fracture the talus can become unstable and subluxate or dislocate. People may complain of ecchymosis (bruising), or there may be an abnormal position, abnormal motion, or lack of motion. Diagnosis is typically by X-ray. Treatment is either via surgery or casting depending on the fracture types.

Footnotes

  1. ^ a b Moore et al. (2010) p.510
  2. ^ a b Ankle at eMedicine Dictionary
  3. ^ a b Brent K. Milner, Ryan S. Fajardo (2007) Musculoskeletal Imaging, in Spencer B. Gay (editor) Radiology Recall p.294
  4. ^ a b Gregory S. Kolt, Lynn Snyder-Mackler (2007) Physical Therapies in Sport and Exercise pp.420-1
  5. ^ a b James G. Adams, Erik D. Barton, Jamie Collings (2008) Emergency Medicine: Expert Consult p.2660
  6. ^ a b Moore et al. (2010) pp.521-2
  7. ^ Ankle+joint at eMedicine Dictionary
  8. ^ Brouwer, B; Ashby, P. (1992). "Corticospinal projections to lower limb motoneurons in man". Exp Brain Res. 89 (3): 649–54. PMID 1644127. 
  9. ^ bones-of-the-foot-tarsals-metatarsals-and-phalanges

References

External links

Media related to Ankle at Wikimedia Commons