Foot/ankle Flashcards
Which position of ankle is there more joint play, PF or DF?
PF. trochlea is wider anterior than posterior, leading to tighter fit
What is function of spring ligament in regards to medial longitudinal arch?
supports arch via preventing talar head dorsiflexion.
Due to this, it is frequently involved in flat foot deformity
What is the Lisfranc joint?
the first set of joints between tarsals and metatarsals
Lisfranc ligament
Strong connection between 2nd metatarsal and medial cuneiform, linking them with 1st ray
Triceps Surae moment arm
much larger than other PF muscles, leading to them contributing majority of force despite only being 40% of muscle mass
Muscles of deep posterior compartment of lower leg
flexor hallucis longus, flexor digitorum longus, tibialis posterior.
Function of tibilias posterior?
support medial longitudinal arch by attachment to medial navicular/cuneiforms
Tib posterior contribution to supination
- primary supinator
- long moment arm and large size means that other muscle unlikely to functionally substitute if muscle is compromised
Tib anterior contribution to supination
Low compared to posterior.
Smaller moment arm
Average subtalar axis
superior 42 degrees, medial 16 degrees
Mechanics of midfoot when hindfoot is pronated
axes of calcaneocubiod and talonavicular joints line up, allowing increased mobility
Which ligament is at risk of failure following PF release
Spring ligament
Which motion of tibia raises medial longitudinal arch of foot?
ER
What is source of tibial motion during gait
Proximal sources (hip/knee musculature)
What is primary source of force for forward progression
Plantarflexors