Session 12: The Ankle Joint

Question 1

articulations of tibia and fibula

Answer 1

Proximal: (superior) tibio-fibular articulation - planar synovial

Intermediate: syndesmoses IO membrane

Distal: tibio-fibular syndesmoses

-held together by anterior/posterior (inferior) distal tibio-fibular ligaments

Question 2

Articulations of ankle joint

Answer 2

Tibia: superior and medial articulatory surface

Fibula: lat. art. surface

Talus: inferior, infero-medial, infero-lateral art. surface

Question 3

ligaments of the ankle

Answer 3

deltoid: supports medial side of the joint, goes from med. mall. to navicular tuberosity of calcaneus
- strongest as it has a superficial and deep component,
- > superficial: ant. (tibionavicular), middle (tibiocalcaneal) and post. (posterior tibiotalar) fibres
- > deep: anterior tibiotalar

Ant. and post. talofibular ligaments: support lat. side of ankle, from lat. mall. -> dorsal and ventral ends of talus

-known as lat. ligaments of ankle

Calcaneofibular: from lat. mall. -> lat. surface of calcaneus

Question 4

deltoid ligament

Answer 4

supports the medial side of the joint, strongest as it has a superf. and deep component:

• superficial: anterior (tibionavicular), middle (tibiocalcaneus) and posterior (posterior tibiotalar)
• deep: anterior tibiotalar

Question 5

movements and classification fo ankle joint

Answer 5

rolling hinge joint (aka ginglymus) - mortise (leg bones form a recess/box distally called a mortise) and tenon (talus is accommodated within the mortise)

movements: dorsiflexion: narrowing of angle between ant. part of leg and dorsal surface of foot - mainly tibialis anterior, also EDL and EHL, fibular branch of sciatic nerve - L4-5
- plantarflexion: widening of angle between dorsal surface of foot and ant. part of leg - mainly gastrocnemius and soleus, assisted by tibialis posterior, FHL and FDL, tibial branch of sciatic nerve - S1-2

Question 6

common injuries affecting ankle joint

Answer 6

dislocation of joint when landing

Frx: usually w/ both med. and lat. aspects due to the ankle being a ring of bones and ligaments

Pott’s frx: combined abduction and med. rotation -> forced excessive eversion -> pulls on extremely strong med. deltoid ligament (often tears off med. malleolus) -> talus then moves lat., shearing off lat. malleolus

• this commonly results in breakage of fibula superior to the tibiofibular syndesmosis
• if the tibia is carried anteriorly the post. margin of the distal end of the tibia is also sheared off by the talus

Question 7

Pott’s frx:

Answer 7

combined abduction and lat. rotation -> excessive eversion -> pulls on extremely strong middle deltoid ligament ->tears off med. malleolus -> talus then moves lat., shearing off lat. mall.

• commonly this results in a frx of the fibula superior to the tibiofibular syndesmosis
• if the tibia is carried anteriorly, the post. margin of the distal end of the tibia is also sheared off by the talus

Question 8

medial arch of foot

Answer 8

formed by calcaneus, talus, navicular, 3 cuneiforms and 3 metatarsals

Question 9

main joints of the foot

Answer 9

There are many joints in the foot, but the three main ones are the subtalar, talocalcaneonavicular and calcaneocuboid joints. These joints allow for inversion and eversion of the foot to occur.

The talocalcaneonavicular and calcaneocuboid joints are sometimes referred to as a collective joint, the transverse tarsal joint.

Subtalar – articulation between the inferior surface of the talus and the superior surface of the calcaneus

Talocalneonavicular - articulation between the talus, the calcaneus and navicular

Calcaneocuboid – articulation between the calcaneus and the cuboid