lower leg and ankle arthrology Flashcards
what are the functions of the interosseous membrane?
-forms a strong bond between the tibia and fibula- stabilises the leg and ankle joints
- facilitates movements of the fibula during ankle movement
-reduces torsional stress on the fibula
-separates muscles of anterior and posterior compartments of the leg
- provides a large surface area for muscle attachment
what joint type is the superior tibiofibular joint?
synovial plane joint
what joint type is the inferior tibiofibular joint?
syndesmosis (fibrous joint)
does any active movement occur at the tibiofibular joints?
no, only passive movements as a result of movement at the talocrural joint
what is the full classification of the talocrural joint?
compound, synovial joint, uni-axial, hinge
what bones articulate to form the talocrural joint?
body of talus, tibia and fibula
describe the articular surface of the superior aspect of the talus
-convex in AP direction
-slightly concave transversely
-surface is broader anteriorly
what ligament is vital for posterior stability of the ankle joint?
transverse tibiofibular ligament
name the static stabilisers of the ankle joint
- fibrous capsule of joint
-transverse tibiofibular ligament
-anterior and posterior ligaments - lateral collateral ligament
- medial collateral(deltoid) ligament
- inferior tibiofibular joint ligaments
- interosseous membrane
describe the lateral collateral ligament of the ankle
strong ligament comprising of 3 bands, reinforces joint capsule laterally
what are the 3 bands of the lateral collateral ligament
- anterior talofibular lig
-calcaneofibular lig - posterior talofibular lig
what are the attachments of the anterior talofibular ligament
runs between anterior border of lateral malleolus and talar neck
what are the attachments of the posterior talofibular ligament
runs horizontally from malleolar fossa to lateral posterior tubercle of talus
what are the attachments of the calcaneofibular ligament
passes from tip of lateral malleolus to the lateral calcaneal surface behind the peroneal tubercle and blends with the joint capsule
describe the deltoid ligament
-medial collateral ligament
-very strong
-consists of 4 bands of fibres
what are the 2 deeper bands of the deltoid ligament?
anterior and posterior tibiotalar ligaments
where do the deeper bands of the deltoid ligaments attach?
attach to medial side of neck and body of talus, blending with the joint capsule
what are the superficial bands of the deltoid ligament?
tibionavicular and tibiocalcaneal ligaments
where do the superior bands of the deltoid ligament attach?
have a continous attachment from the navicular tuberosity to the sustentaculum tali, including the spring ligament
what is the role of the collateral ligaments?
-maintaining stability at the ankle joint
- allowing movements at the ankle joint
what movements occur at the talocrural joint during dorsiflexion?
-wide part of trochlear surface of talus rocks backwards into posterior tibiofibular mortise joint, pushing tibia and fibula apart
-talus becomes wedged between malleoli
what movements occur at the tibiofibular joints during dorsiflexon?
- fibula displaced laterally
- increased tension in interosseous membrane and the ligaments
- superior gliding of fibula
- passive movements
what is the normal range of movement for dorsiflexion?
20-30 degrees
what are the limiting factors of dorsiflexion?
- Lateral collateral ligament
-Deltoid ligament - posterior part of joint capsule
- extent of articular surface
what is the close packed position of the talocrural joint?
dorsiflexion- there is maximum contact between the talus and the mortise joint
