The Foot & Ankle Flashcards
What are the components of the hindfoot?
talus & calcaneus
What are the components of the midfoot?
medial cuneiform, intermediate cuneiform, lateral cuneiform, navicular, cuboid
What are the components of the forefoot?
metatarsals (5) & phalanges (14)
What are the 2 primary ligaments that support the ankle joint laterally?
anterior talofibular ligament (ATFL) & calcaneofibular ligament
Which ankle movements are checked by the calcaneofibular ligament?
inversion & adduction of the calcaneus relative to the fibula
What motion is checked by the posterior talofibular ligament?
external rotation of the talus
What actions does the fibularis longus perform?
- subtalar pronation
- supports transverse arch of foot
- plantarflexion of 1st metatarsal
What actions does the fibularis brevis muscle perform?
- subtalar pronation
- forefoot abduction
What 3 muscles comprise the deep posterior compartment of the lower leg? Which is the strongest?
- flexor hallucis longus
- flexor digitorum longus
- tibialis posterior (strongest by a large margin)
What do the cross-sectional area and moment arm of the posterior tibialis tell us about its role in ankle movement?
larger moment arm & higher cross-sectional area compared to the other deep posterior compartment muscles suggest that it is the dominant supinator of the subtalar joint
What is the action of the muscles of the deep posterior compartment of the lower leg?
subtalar joint supination (also hypothesized to raise the medial arch & plantarflex the toes)
What are the 4 muscles of the anterior compartment of the lower leg?
1, tibialis anterior
- extensor digitorum longus
- extensor hallucis longus
- fibularis tertius
Explain why the talocrural joint is more stable in dorsiflexion and less stable in plantarflexion.
the trochlea of the talus is wider anterior than posterior, so it sits more snugly in the mortise (distal tibia/fibula) in dorsiflexion.
Describe the movements of the calcaneus and talus during supination and pronation. How do these movements affect the medial longitudinal arch?
- Supination: calcaneus inverts (frontal plane), while talus abducts (transverse) & dorsiflexes (sagittal); medial longitudinal arch rises
- Pronation: calcaneus everts (frontal), while talus adducts (transverse) & plantarflexes (sagittal); medial longitudinal arch lowers.
What are the two most important joints that contribute to the locking mechanism of the midfoot?
transverse tarsal joints (talonavicular & calcaneocuboid joints)
Describe the Windlass mechanism.
Extension (dorsiflexion) of the toes increases tension on the plantar fascia, which in turn supports the medial longitudinal arch.
What is the relationship between tibial rotation and arch height?
tibial ER results in an increase in the height of the medial longitudinal arch; IR results in a lower arch
How does the hip affect arch height? Is the tibial controlled by more proximal or distal forces/positions?
Tibial rotation affects arch height & is controlled more by proximal forces from the hip (femoral rotation) than distal foot/ankle positioning with orthoses.
What group of muscles are primarily responsible for propulsion and support during gait?
plantar flexors
During what phases of gait are the plantar flexors most active?
mid-stance to just prior to toe off
Describe the sagittal plane movement of the ankle during gait
- slight dorsiflexion at initial contact
- moves to neutral at foot flat (in first 10%-15% of stance phase)
- gradually moves into dorsiflexion (peaking at 70%-80% of stance phase)
- rapidly plantar flexes to toe off (pre-swing)
What is the role of the soleus during gait?
slows the tibia after foot flat
In older patients, what is the relationship between ankle strength and hip muscle activity during gait? How is this addressed clinically?
- Elderly patients tend to have decreased plantar flexor strength & diminished push-off, so they tend to rely on a hip pull-off contribution during walking.
- Cueing patients to increase their ankle push-off during gait lowers hip flexor and extensor activity during gait
Describe the movement of the subtalar joint throughout the gait cycle.
- pronation/eversion from initial contact to foot flat (10%-15% of stance)
- rapidly supinates/inverts during terminal stance (peaks near 90% of stance)