Ankle Joint
Table of Contents
The term ankle refers specifically to the talocrural joint defined as articulation between distal tibia and fibula proximally and body of talus distally . Ankle is synovial hinge joint with a joint capsule and associated ligaments.
Proximal Articular surfaces of ankle joint
The proximal segment of the ankle is composed of the concave surface of the distal tibia (know as the tibial plafond) and of the tibial and fibular malleoli.
These three facets form an almost continuous concave joint surface that extends more distally on the fibular (lateral)side than on the tibial(medial)and more distally on the posterior margin of the tibia than on the anterior margin.Β
The structure of the distal tibia and two malleoli resembles and is referred to as a mortise. A common example of a mortise is gripping part of a wrench . Either the wrench. Either wrench can be fixed ( fitting a bolt of only one size ) or it can be adjustable ( permitting use of wrench on a variety of bolt sizes).
The proximally tibiofibular joint is a plane synovial joint formed by the articulation of the head of fibula with posterolateral aspect of the tibia . The facets of the proximal tibiofibular joint are fairly flat and vary individual to individual .Here , a convex tibial facets and concave fibular facets
Distal Articular Surfaces
The body of the talus forms the distal articulation of the ankle joint . The body of the talus has three articular surfaces: a large lateral (fibular) facet, a smaller medial (tibial) facet and a trochlear surfaces has a central groove that runs at a slight angle to the head and neck of talus . The articular cartilage covering the trochlea is continuous with the cartilage covering the more extensive lateral facet and smaller medial facets .
The distally Tibiofibular Joint is a syndesmosis, or fibrous union , between the concave facet of the tibia and the convex facets of the fibula . The distal tibia and fibula are separated by fibro adipose tissue .
- No joint capsule
- They have several ligament which contribute to stability at both joint .The ligament of the distal tibiofibular joint are primarily responsible for maintaining stability . The anterior and posterior tibiofibular ligaments and interosseous membrane provide support to the distal tibiofibular joint
Capsule and Ligament
The capsule of ankle joint is fairly thin and especially weak anteriorly and posteriorly . Therefore , the stability of the ankle depends on an intac ligamentous structure. The ligaments that supports the proximal and distal tibiofibular joints ( the crural tibiofibular interosseous ligament , the anterior and posterior tibiofibularligament , and the tibiofibular interosseous membrane) are important for stability of the stability of the ankle.
Medial collateral Ligament
Medial collateral Ligament is commonly the deltoid ligament. . the deltoid ligament is fan shaped . it has superfial and deep fibers that arise from the border of the tibial malleolus and insert in a continuous line anterior to posterior on the navicular talus , and calcaneus.
Lateral collateral ligament
The LCL is composed of three distinct bands that are commonly referred to as separate ligament. These are the anterior and posterior talofibular ligaments. These are the anterior and posteriortalofibular ligaments and calcaneofibular ligament.
The inferior band of the superior peroneal retinaculum which lies close and parallel to the calcaneofibular ligament , appers inforce that ligament . because the ankle collateral ligament and reticulae also contribute to stability of the subtalar joint .
Subtalar joint
The Subtalar joint articulation between the talus superiorly and calcaneus inferiorly .
Ligament
Subtalar joint is stable joint that is rarely dislocated . It has a congruent osseous anatomy as well as strong ligamentous support . There is various ligament such as ;
- Calcaneofibular Ligament
- Cervical Ligament
- lateral talocalcaneal
- Interosseoustalocalcaneal ligament
Tarsometatarsal Joint (TMT)
The Tarsometatarsal Joint (TMT)are plane synovial joint formed by the distal row of tarsal bones and the bases of metatarsels. The First TMT joint composed of the articulation between the base of the first metatarsel and medial cuneform bone and has it own articular capsule. The second TMT joint is composed of the articulation base of second metatarsel with mortise formed by middle cuneform bone and the sides of the medial and lateral cuneiform bones.
Β The third TMT , formed by third metatarsel and lateral cuneform , shares a capsule with the second TMT joint .
Metatarsophalangeal Joint(MTP)
The five metatarsophalangeal joint are condyloid synovial joint with two degree of freedom : extension /flexion , abduction /adduction , dorsiflexion and plantarflexion.MTP joint are formed proximally by the convex heads of the metatarsels and distally by the concave bases of the metatarsels and distally by the concave bases of the proximal phalanges
Interphalangeal joint
The Interphalangeal joint (IP) joints of the toes are synovial hinge joint with one degree of freedom : flexion / extension .
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