Ankle Joint Flashcards
Why is the femur angled?
so the knees can be closer to the midline and under the centre of gravity
Where is the tibial tuberosity?
proximal of the anterior shaft of tibia
What attaches to the tibial tuberosity?
patella tendon, mediating the quadricep muscles
When we get a fracture on the tibia, we are likely to get a fracture on the fibula as well. Why is that?
tibia and fibula form a ring
Why is the distal tibia more likely to fracture?
It is relatively thin and does not have a good blood supply
What is the name of the oblique line down the posterior tibia?
soleal line
What is the muscle type of soleus?
it’s a slow twitch muscle, working at a steady and low level, important for maintaining posture
Why do we tend to fall forward when we faint in the up right position?
We lose the soleus support, and the centre of gravity will push the body forward
If we fracture our fibula, how long will it take before we can move again?
Pretty quickly, because the fibula is non-weight bearing and has good blood supply
Because of the extensive blood supply of the fibula, we often use the fibula as _______
bone graft
T/F interosseous membrane of the tibia and fibula is a completely sealed membrane
False, it has two foramen, one superiorly, one inferiorly
What kind of joint is the superior tibialfibular joint?
plain synovial
What are the ligaments supporting the superior tibialfibular joint?
anterior ligament, posterior ligament and the lateral collateral ligament
T/F inferior tibialfibular joint has the same joint type as superior tibialfibular joint
False, it is a fibrous syndemosis, hence stronger than the superior joint
Why have we lost pronation and supination in our lower limbs?
humans are bipedal. We trade the mobility for stability of lower limbs
What are the three crucial bones of the ankle (for most of the movements)
talus
calcaneus
navicular
T/F Lower limbs undergo internal rotation during development
True, so the big toe is medial.
External rotation occurs with the upper limbs
What’s the common location for “march fracture”
the second metatarsal, because it is the thinnest and the articulation is wedged between first and third metatarsal. Hence stress fractures are very common
What are the functions of seasamoid bones?
provide a passage for tendons, so they have a cushioning effect and also create a space for neurovascular structures to pass
Where in the bone does an accessory bone form?
in the secondary ossification centres
What are two common places for accessory bones in the lower limbs?
in the talus or around the navicular
List the three main joints associated with the ankle
talocrural, above the talus
subtalar joint, below the talus
midtarsal joint, anteriorly
What does the “mortice” compose of?
body of the talus surrounded between the malleoli, protected by posterior tibiofibular ligament and inferior transverse ligament
What kind of joint is the talocrural joint? What movements does it produce?
synovial hinge joint, producing dorsiflexion and plantarflexion
Why is dorsiflexion often associated with eversion at the ankle joint?
Because of the oblique axis between the two malleoli, lateral one extending more inferiorly
T/F the ankle is more stable on plantarflexion
False. On plantarflexion, the posterior, narrower part of the talus is enclosed by the malleoli. There is therefore a greater range of movement, and less stable
How far does the ankle joint capsule extend?
down to the neck of the talus
T/F The lateral collateral ligaments of the ankle are weaker than the medial collateral ligaments
True, because they are three separate bands while the medial ligaments are almost fused
What do the lateral collateral ligaments of the ankle attach to?
to the calcaneus, anterior talus, and posterior talus
Why is the anterior talofibular ligament (one of the lateral collateral ligaments) most likely to be injured
Ankle is mostly injured on plantarflexion. In that position, the ATL is stretched, contributing to the risk of injury
An ankle ligament injury laterally is often accompanied by a generalised soreness. How does that occur?
Due to muscular strain on fibularis longus and brevis, which travels posterior to the lateral malleolus
What is a “Pott’s fracture”
Fracture of the fibula shaft together with fracture of malleoli
What movement occurs at the subtalar joint?
inversion and eversion
What sits on the spring ligament? What is the function of this ligament?
the head of the talus
maintains the orientation of the head of talus
When you run and land on your foot, is the foot in eversion or inversion?
foot down = dorsiflexion = eversion
Where is the sinus tarsi and what is its function?
In the gap between TCN joint and the posterior subtalar joint
it contains the blood supply, via vascular sling through the sinus tarsi
What are the two midtarsal joints?
TCN and calcaneocuboid
What movements occur at the calcaneocuboid joint?
pronation and supination
arch support in shoe design is based on the degree of this movement
Where do Lisfranc fractures occur?
at the tarsometatarsal joints
Metatarsophalangeal joints are all ______ joints
condylar
T/F Lateral arch of the foot is always higher than the medial arch
False, medial arch is higher
