Ankle and Foot Flashcards
What type of chain is the foot when in contact with the ground?
Closed kinematic chain
How many synovial joints are in the foot and ankle?
30
How many synovial joints play a biomechanical role in function?
3
What are the three important joints?
Talocrural
Subtalar
Midtarsal
What are the functions of the foot?
Acts as a support base for minimal muscle effort
Torque Converter of tibia and fibula during stance
Flexibility for adaptation over uneven surfaces
shock absorption function during the pronatory response (IC-MSt)
Rigid lever during the supinator response (MSt-TS) to efficiently transfer forces
What are the six major joints of the foot?
Talocrual Subtalar Midtarsal Intertarsal Tarsal-metatarsals Metatarsal-phalangeal
What makes up the talocrual joint, how many DOF, and what is it designed for?
Articulation of distal tibia and fibular with the head of the talus. (tongue and groove)
1 degree of freedom
Designed for stability
What is an important aspect of the Talus?
It is 2-4 mm wider anteriorly
What is the Open pack/Resting position of the Talocrual?
10 degrees of plantarflexion, midway between inversion and eversion
What is the closed packed position o the talocrual?
Maximum dorsiflexion
What are the osteokinematics of the Talocrual?
Flexion and Extension
When providing traction or distraction of the talocrual joint what are the angles?
10 degrees medial deflected from the long axis o the lower extremity
What is the direction of glide for the talocrual?
30 degrees deflected from the sagittal Anterior glide(increase Plantarflexion)-anterior/lateral Posterior glide(increase dorsiflexion)-posterior/medial
What makes up the subtalar joint and how many degrees of freedom?
Articulation of talus and calcaneus
3 degrees of freedom
What makes up the Midtarsal joint?
Talo-navicular joint
Calcaneal-cuboid joint
What is the open pack/Resting position of the midtarsal joint?
Midway between extreme ROM
What is the closed packed position of the midtarsal joint?
Supination
What are the two arches in the foot?
Medial longitudinal arch
Transverse arch
What do the arches do and where does support come from?
Create stability and resiliency in the loaded foot
Primary support: spring ligament
Secondary support: Long and short plantar ligaments and plantar fascia
What are the four aspects of the medial longitudinal arch?
Based posteriorly at the calcaneus
Based anteriorly at the metatarsal heads
Continuous both medially and laterally
Referenced from medial side
What are the two aspects of the transverse arch?
Seen through tarsals with the intermediate cuneiform at the apex
Seen through metatarsals with 2nd metatarsal at the apex
What are two general aspects of the plantar arches?
During stance the arches flatten slightly
During push-off giat the medial longitudinal arch increases due to the pull of the plantar aponeurosis during toe extension (Windlass effect)
What is pes planus and what can it lead to?
Flat foot
Poorly supported medial longitudinal arch with weight-bearing
Pronated foot
Leads to excess stress on soft tissue structures
What is pes cavus and what does it not allow?
Abnormally raised medial longitudinal arch
Supinated foot
Doesn’t allow normal shock absorption