Ankle
Encyclopedia
The ankle joint
is formed where the foot
and the leg
meet. The ankle, or 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 bone
in the foot. The articulation between the tibia and the talus bears more weight than between the smaller fibula and the talus.
The term ankle is used to describe structures in the region of the ankle joint proper.
, probably connected in origin with the Latin "angulus", or Greek
"αγκυλος", meaning bent.
, 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." The joint surface of all bones in the ankle are covered with articular cartilage
.
, 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
.
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. However, in the setting of an ankle fracture the talus can become unstable and subluxate
or dislocate. People may complain of ecchymosis
(brusing), 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.
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
is formed where the foot
Foot
The foot 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 up of one or more segments or bones, generally including claws...
and the leg
Human leg
The human leg is the entire lower extremity or limb of the human body, including the foot, thigh and even the hip or gluteal region; however, the precise definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle.Legs are used for standing,...
meet. The ankle, or talocrural joint, is a synovial
Synovial joint
A Synovial joint, also known as a diarthrosis, is the most common and most movable type of joint in the body of a mammal. As with most other joints, synovial joints achieve movement at the point of contact of the articulating bones....
hinge joint that connects the distal ends of the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
and fibula in the lower limb with the proximal end of the talus bone
Talus bone
-External links:* *...
in the foot. The articulation between the tibia and the talus bears more weight than between the smaller fibula and the talus.
The term ankle is used to describe structures in the region of the ankle joint proper.
Name derivation
The word ankle or ancle is common, in various forms, to Germanic languagesGermanic languages
The Germanic languages constitute a sub-branch of the Indo-European language family. The common ancestor of all of the languages in this branch is called Proto-Germanic , which was spoken in approximately the mid-1st millennium BC in Iron Age northern Europe...
, probably connected in origin with the Latin "angulus", or Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
"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.Bones
The boney architecture of the ankle consists of three bones: the tibiaTibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
, the fibula, and the talus
Talus
Talus may refer to:* Talus , a sloped portion of a fortified wall* Talus, California, a community in Inyo County* Talus bone, an ankle bone* Talus, fictional planet in Star Wars...
. 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." The joint surface of all bones in the ankle are covered with articular cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
.
Ligaments
The ankle joint is bound by the strong deltoid ligament and three lateral ligaments: the anterior talofibular ligamentAnterior talofibular ligament
The anterior talofibular ligament passes from the anterior margin of the fibular malleolus, forward and medially, to the talus bone, in front of its lateral articular facet. It is one of the lateral ligaments of the ankle and prevents the foot from sliding forward in relation to the shin...
, the posterior talofibular ligament
Posterior talofibular ligament
The posterior talofibular ligament, runs almost horizontally from the depression at the medial and back part of the fibular malleolus to a prominent tubercle on the posterior surface of the talus immediately lateral to the groove for the tendon of the flexor hallucis longus....
, and the calcaneofibular ligament
Calcaneofibular ligament
The calcaneofibular ligament is a narrow, rounded cord, running from the apex of the fibular malleolus downward and slightly backward to a tubercle on the lateral surface of the calcaneus.It is covered by the tendons of the Peronæi longus and brevis....
.
- The deltoid ligament supports the medial side of the joint, and is attached at the medial malleolus of the tibia and connect in four places to the sustentaculum taliSustentaculum taliAt the upper and forepart of the medial surface of the calcaneus is a horizontal eminence, the sustentaculum tali , which gives attachment to the plantar calcaneo-navicular ligament, tibiocalcaneal ligament, and medial talocalcaneal ligament.This eminence is concave above, and articulates with the...
of the calcaneus, calcaneonavicular ligament, the navicular tuberosity, and to the medial surface of the talus. - The anterior and posterior talofibular ligaments support the lateral side of the joint from the lateral malleolus of the fibula to the dorsal and ventral ends of the talus.
- The calcaneofibular ligament is attached at the lateral malleolus and to the lateral surface of the calcaneus.
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
Syndesmosis
A syndesmosis is slightly movable articulation where the contiguous bony surfaces are united by an interosseous ligament, as in the inferior tibiofibular articulation...
, 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
High ankle sprain
A high ankle sprain, also known as a syndesmotic ankle sprain, is a sprain of the syndesmotic ligaments that connect the tibia and fibula on the lower leg. Syndesmotic ankle sprains are known as high because their location on the lower leg is above the ankle...
.
The boney architecture of the ankle joint is most stable in dorsiflexion. Thus, a sprained ankle
Sprained ankle
A sprained ankle, also known as an ankle sprain, twisted ankle, rolled ankle, ankle injury or ankle ligament injury, is a common medical condition where one or more of the ligaments of the ankle is torn or partially torn.-Cause:...
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
Anterior talofibular ligament
The anterior talofibular ligament passes from the anterior margin of the fibular malleolus, forward and medially, to the talus bone, in front of its lateral articular facet. It is one of the lateral ligaments of the ankle and prevents the foot from sliding forward in relation to the shin...
(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
Calcaneofibular ligament
The calcaneofibular ligament is a narrow, rounded cord, running from the apex of the fibular malleolus downward and slightly backward to a tubercle on the lateral surface of the calcaneus.It is covered by the tendons of the Peronæi longus and brevis....
.
Fractures
Symptoms of an ankle fractureAnkle fracture
An ankle fracture is a break of the ankle bones. It is typically diagnosed by X-ray. Treatment is with either casting or surgery.-Signs and symptoms:...
can be similar to those of ankle sprains (pain
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
), 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. However, in the setting of an ankle fracture the talus can become unstable and subluxate
Subluxation
A subluxation may have different meanings, depending on the medical specialty involved. It implies the presence of an incomplete or partial dislocation of a joint or organ. The World Health Organization defines both the medical subluxation and the chiropractic subluxation...
or dislocate. People may complain of ecchymosis
Ecchymosis
An ecchymosis is the medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.-Presentation:...
(brusing), or there may be an abnormal position, abnormal motion, or lack of motion. Diagnosis is typically by X-ray
Radiography
Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....
. Treatment is either via surgery or casting depending on the fracture types.