20. Familiar with the structure of the ankle joint: the articular surfaces, the ligaments and capsule & the movements available Flashcards
What is the name of the ankle joint?
The talocrural joint
What is another name for the talocrural joint?
The tibiotalar joint
What type of joint is the talocrural joint?
A synovial hinge joint, uniaxial
What is a uniaxial joint?
Motion occurs on one plane
Definition of a synovial hinge joint:
The joint between two bones that allows movement only in one plane
Which movements does the talocrural joint allow?
Plantar flexion and dorsiflexion
Dorsiflexion and plantar-flexion occur in which plane?
The sagittal plane
Which 3 bones form the ankle joint?
Tibia
Fibula
Talus
What is a mortise?
A bracket shaped socket, covered in hyaline cartilage.
It is formed from the binding of the tibia and fibula by strong tibiofibular ligaments
The body of the talus fits into the mortise formed by the tibia and fibula
Shape of the articulating part of the talus
The articulating part of the talus is broad anteriorly, and narrow posteriorly
Describe the stability of the talocrural joint during dorsiflexion and plantarflexion
Dorsiflexion: the anterior part of the talus is held in the mortise, and the joint is more stable
Plantarflexion: the posterior part of the talus is held in the mortise, and the joint is less stable
Why is the talocrural joint most stable in dorsiflexion?
Because the anterior aspect of the talus forms a wedge between the lateral and medial malleoli
2 main sets of ligaments of the ankle joint:
Medial ligaments
Lateral ligaments
Another name for the medial ligament:
Deltoid ligament
Description of the medial ligament:
Consists of 4 ligaments which fan out from the malleolus
Action of the medial ligament
Resist over-eversion of the foot
Names of the 4 ligaments included within the medial/deltoid ligament of the ankle:
Posterior tibiotalar part of the medial ligament
Tibiocalcaneal part of the medial ligament
Tibionavicular part of the medial ligament
Anterior tibiotalar part of the medial ligament
Origin and insertion of the anterior tibiotalar part of the medial ligament
Origin: Medial malleolus of tibia
Insertion: Neck of the talus
Origin and insertion of the tibiocalcaneal part of the medial ligament
Origin: medial malleolus
Insertion: sustentaculum tali of the calcaneus
Origin and insertion of the tibiocalcaneal part of the medial ligament
Origin: medial malleolus
Insertion: navicular bone
Origin and insertion of the tibiocalcaneal part of the medial ligament
Origin: medial malleolus
Insertion: posterior talus
Action of the lateral ligament of the ankle joint:
Resists over-inversion of the foot
Name 3 ligaments that make up the lateral ligament
Anterior talofibular ligament
Posterior talofibular ligament
Calcaneofibular ligament
Origin and insertion of the posterior talofibular ligament
Origin: posterior aspect of the lateral malleolus
Insertion: posterolateral talus
Origin and insertion of the anterior talofibular ligament
Origin: anterior edge of the lateral malleolus
Insertion: neck of the talus
Origin and insertion of the calcaneofibular ligament
Origin: anterior aspect of the lateral malleolus (below the anterior talofibular ligament)
Insertion: Lateral surface of the calcaneus
Action of the lateral collateral ligament complex
Resist inversion of the ankle joint
3 ligaments included in the lateral collateral ligament complex
Anterior talofibular ligament
Posterior talofibular ligament
Calcaneofibular ligament
General origin and insertion of the lateral collateral ligament complex
Origin: Lateral malleolus
Insertion: Talus & calcaneous
Describe the capsule of the ankle joint:
The proximal aspect of the joint capsule is attached to the margins of the articular surfaces of the medial malleolus and lateral malleolus
The distal aspect of the joint capsule is attached to the margins of the taller trochlear surface
The joint capsule is relatively weak and thin, but strengthened medially and laterally by strong collateral ligaments
The internal surface of the capsule is lined by synovial membrane which projects into the distal tibiofibular joint up to the interosseous tibiofibular ligament.
