Ankle joint Flashcards
What type of synovial joint is the ankle
Hinge (one plane)
What movements does the ankle joint permit
Dorsiflexion and plantarflexion
What are the articulating surfaces at the ankle joint
Tibia and fibula produce a bracket shaped socket called a mortise
Body of talus fits into the mortise
Significance of articulating talus shape in terms of movement
Body of talus is wider anteriorly so during dorsiflexion, the talus gets wedged between the malleoli
This means dorsiflexion is more limited and more stable than plantarflexion
What are the groups of ankle ligaments
Collateral ligaments
Medial ligament (deltoid)
Lateral ligament
What are the collateral ligaments
Medial - from tibia to talus, from tibia to calcaneus
Lateral - from fibula to talus, room fibula to calcaneus
What is the medial ligament made up of
Anterior tibiotalar
Posterior tibiotalar
Tibial navicular
Tibial calcaneal
Where does the medial ligament originate
Medial malleolus
Where does the lateral ligament originate
Lateral malleolus
What is the lateral ligament made up of
Anterior talofibular
Posterior talofibular
Calcaneofibular
Where do plantar flexors pass at the ankle
Posterior to malleoli
Where do dorsiflexors pass at the ankle
Anterior to malleoli
Where do inverters insert
Medial aspect of foot
Where do everters insert
Lateral aspect of foot
Where is the joint capsule lax
Anterior and posterior
Neurovascular supply of ankle joint
Arterial - Malleolar branches of anterior tibial, posterior tibial and fibular arteries
Innervation - tibial and deep fibular nerves
What is an ankle sprain
Partial or complete tear in ankle ligaments
How do ankle sprains usually occur
Excessive inversion in a plantar flexed foot
Which ligament is most likely to get damaged in an ankle sprain
Anterior talofibular ligament
Lateral ligament is weaker than medial
Lateral ligament resists inversion
What’s a Potts fracture
Bimalleolar (medial and lateral malleoli) or trimalleolar (medial and lateral malleoli, and distal tibia) fracture
How do Potts fractures occur
Forced eversion pulls on medial ligament causing an avulsion fracture of medial malleolus
Talus moves laterally, breaking off the lateral malleolus
Tibia forced anteriorly, shearing off the distal part against the talus
