Flashcards in The foot and ankle Deck (59)
How is the ankle joint formed?
articulation between the distal tibia and fibula with the talus
What 2 movements does the synovial hinge joint allow?
What is the osteoology of the ankle?
3. medial malleolus - distal tibia
5. lateral malleolus - distal fibula
6. calcaneus - heal bone
7. fibular trochlear
What is the stability of the ankle joint like?
it is stable
What makes the ankle joint stable?
1. good congruity between malleolar mortice and trochlea - the malleoli grip the talus
2. involves strong ligaments
What ligaments make the ankle joint stable?
1. distal part - interosseous membrane
2. anterior and posterior tibiofibular ligaments
Where is the trochlea wider?
wider anteriorly than posteriorly
What is the movement of the trochlea during dorsiflexion and what does this movement do to the tibia and fibula?
the anterior part of the trochlea moves between the malleoli
spreads the tibia and fibula slightly increasing their grip on the talus
What is the most stable position of the ankle?
What are the lateral ligaments of the ankle joint that contribute to stability?
1. posterior talofibular ligament
2. anterior talofibular ligament
3. calcaneofibular ligament
What is the weakest ligament of the ankle joint?
What is the medial ligament attached to and where does it fan out to?
- attaches to the medial malleolus
- fans out to attach to talus, navicular and calcaneus
What is the medial ligament also called?
deltoid ligament due to it's resemblance to the greek letter delta
What are the movements of the ankle joint? (4)
What muscles does dorsiflexion involve and what nerve and artery are these muscles supplied by?
muscles of the anterior compartment of the leg
deep fibular (perineal) nerve
anterior tibial artery
What muscles does plantar flexion involve and what nerve and artery are these muscles supplied by?
muscles of the posterior compartment of the leg - except popliteus
supplied by the tibial nerve
posterior tibial artery
Where does inversion and eversion usually occur?
- at subtler joint - with some movement in the transverse tarsal joint
Where does the subtler joint lie?
between the talus and underlying calcaneus
What type of injuries are most ankle sprains? (inversion or eversion?)
with twisting of the plantar-flexed foot
What ligament is usually injured in an ankle sprain?
How quickly do ligaments heal in ankle sprains and why?
they heal slowly
as ligaments are relatively avascular
What happens to the growth and strength of a ligament when it is detached from bone?
fibres don't grow back into the bone as extensively
healed ligament is usually weaker
What do torn ligaments predispose the ankle joint to and why?
They predispose the ankle joint to dislocation
As the ankle joint is less stable
Which ligament is weaker - the lateral or medial ligament and which part in particularly?
the lateral ligament
particularly the anterior talofibular part
What do you look for in a normal ankle joint x ray?
1. even joint space all the way
What can been seen on a x ray of a patient with osteoarthritis?
loss of joint space
loss of cartilage space
contour of talus is gone
What types of fractures can you have at the ankle joint?
1. fracture at distal fibula - lateral malleolar fracture
2. left ankle bimalleolar fracture
3. open fracture of lateral side of leg
4. fracture of fibula
What type of dislocation can you have at the ankle joint?
1. anterior dislocation of the distal talus of the tibia
What ligament can an eversion injury pull on and avulse and how can this fracture the fibula?
pull on strong medial ligament
causes avulsion of medial malleolus
fracture of fibula - lateral rotation of the talus