Articulating Surfaces

Question 1

Describe the articular surfaces of the talocrural joint

Answer 1

Distal tibia
- rectangular with bony protuberance projecting ~ 1cm distally = medial malleolus (covered in hyaline cartilage)

Distal fibula

• bony protuberance on lateral aspect ~ 2cm distal to joint line = lateral malleolus
• internal medial aspect articulates with lateral aspect of talus - covered in hyaline cartilage

Talus
- Talar body is wider anteriorly than posteriorly (wedge shaped)
- Convex antero- posteriorly but concave from side to side
3 articular facets all covered in hyaline cartilage
- superior facet = trochlea
- medial facet (for medial malleolus)
- lateral facet (for lateral malleolus)

Question 2

Describe the articulating surfaces of the subtalar joint

Answer 2

Between inferior concave facets of talus (hyaline cartilage)
- posterior facet on inferior talar body
- medial facet on inferior talar head
- anterior facet on inferior talar head
& Convex facets on superior calcaneus (hyaline cartilage)
- posterior facet on mid-superior calcaneal surface
- middle facet on sustentaculum tali
- anterior facet on superomedial aspect of distal calcaneus

• Between posterior facets and other 2 = 2 sulcus’ which form tarsal sinus

Question 3

Describe the articular surfaces of the mid-tarsal joint

Answer 3

TCN joint:

• head of talus =ball
• socket = concave facet on proximal navicular, sustentaculum tali & calcaneus (supported by spring + calcaneonavicular - part of birfurcate - ligaments)
• Covered in hyaline cartialge

CC joint

• Between anterior concave surface of calcaneus and posterior convex surface of cuboid
• Covered in hyaline cartilage