Introduction/General
The ankle joint is composed of various partial joints. The two largest joints are: Together they form a functional unit and are called Articulatio cylindrica. The ankle joint is one of the most stressed joints of the body, since it has to carry the entire body mass with every step. In addition to these, there are also smaller joints of the tarsal bones, which are, however, strongly fixed by ligaments and therefore hardly moveable.
- The upper (OSG)
- And lower ankle joint (USG).
Upper ankle joint (OSG)
The upper ankle joint (Articulatio talocruralis) is composed of the articular surfaces of the malleolar fork and the anklebone (talus). The malleolar fork is formed by the distal end of the tibia and fibula. The anklebone is enclosed by the malleolar fork on both sides and is therefore of decisive importance for the stability of the joint.
The upper ankle joint is a purely hinged joint and can therefore only perform one movement. This consists of raising the tip of the foot (dorsal extension) by approx. 20° and lowering the tip of the foot (plantar flexion) by approx.
30°. The joint capsule surrounds both ends of the tibia and fibula, as well as the ankle bone. As a result, the malleolar fork (outer and inner ankle) lies outside the joint capsule and is therefore very prone to injury.
The joint itself is also fixed by various other ligaments:
- On the inner side of the ankle is the Ligamentum deltoideum (Syn. Lig. Collaterale mediale) which consists of four parts (Pars tibionavicularis, Pars tibiotalaris anterior and posterior and Pars tibiocalcanea).
It runs between the inner malleolus (malleolus medialis) in a fan shape to the talus, calcaneus and navicular bone.
- Also at the outer ankle, a ligament stretches from the fibula to the ankle bone (Lig. Talofibulare anterius and posterius),
- As well as a band from the fibula to the calcaneus. Through this the upper ankle joint is secured mainly by the inner and outer ligamentous apparatus.
