Ankle/Foot Flashcards
What does the ankle primarily refer to?
talocrural joint: articulation among tibia, fibula, and talus
What does foot refer to?
all tarsal bones and joints distal to ankle
What is the rearfoot?
hindfoot) consists of talus, calcaneus, and subtalar joint
What is the midfoot?
consists of remaining tarsal bones, including transverse tarsal joint and distal intertarsal joints
What is the forefoot?
consists of metatarsals and phalanges, including tarsometatarsal joints
What transfers 10% of body weight?
shaft of fibula
Distal end of tibia twisted externally around its long axis approximately______relative to its proximal end
20-30 degrees
What is the wrist referred to as?
lateral tibial torsion, based on orientation of bone’s distal end relative to its proximal end
What are the major joints of the ankle?
talocrural, subtalar, and transverse tarsal joints
70% of the talus surface is covered with what?
articular cartilage
Plane and AOR of dorsiflexion and plantar flexion
parallel to sagittal plane
ML AOR
Plane and AOR of eversion and inversion?
parallel to frontal plane
AP AOR
Plane and AOR of abduction and adduction?
parallel to horizontal plane and vertical AOR
Pronation defined as motion that has elements of:
Eversion, abduction, and dorsiflexion
Supination defined as motion that has elements of:
Inversion, adduction, and plantar flexion
What provides major source of natural stability to ankle?
confining shapr of talocrural joint
What percentage of compressive forces pass through the talus and tibia?
90-95%
What percentage of compressive forces pass through lateral region of talus and fibula?
5-10%
Arthrokinematics of dorsiflexion at talocrural joint:
talus rolls forward relative to leg and slides posteriorly
Arthrokinematics of plantar flexion at talocrural joint:
talus rolls posteriorly as bone slide anteriorly
What can extreme and violent dorsiflexion of ankle (leg over foot) do:
- can injure collateral ligaments
- injure ligaments that support distal tibiofibular joint and interosseous membrane (high ankle sprain)
What is the loose packed position of the talocrural joint:
full plantar flexion (slackens most collateral ligaments of the ankle)
Pronation and supination during non weight-bearing activities:
calcaneus moves relative to fixed talus
In weight bearing (stance phase of walking) pronation and supination occur:
as calcaneus remains relative stationary
What are the three articulations of the subtalar joint?
the posterior, middle, and anterior facets of calcaneus and talus
Prominent posterior articulation of subtalar joint occupies about what?
70% of total articular surface area
AOR of the subtalar joint:
pierces lateral-posterior heel and courses through subtalar joint in anterior, medial, and superior directions
Where is the AOR of the subtalar joint positioned?
42° from horizontal plane and 16° from sagittal plane
Pronation and supination of subtalar joint occurs:
as calcaneus moves relative to talus (or vice versa when foot planted) in arc perpendicular to AoR
What two of the three main components of pronation and supination are strongly evident:
inversion/eversion
abduction/adduction
Pronation has main components of:
eversion and abduction
Supination has main components of
inversion and adduction
Inversion exceeds eversion by:
nearly double
inversion=22.6 degrees
eversion=12.5 degrees
What composes the mid-tarsal joint:
Talonavicular joint
Calcaneocuboid joint
The mid tarsal joint connects:
rearfoot and midfoot
The tarsal joint moves through what kind of path?
more oblique, equally through all three planes
What joints function cooperatively to control most of pronation and supination posturing of entire foot?
transverse tarsal and subtalar joints
Transverse tarsal joints allow for what of midfoot while standing on uneven surfaces?
pronation/supination
What does the talonavicular joint resemble?
ball and socket
What does the talonavicular joint provide?
substantial mobility to medial (longitudinal) column of foot
What is mobility of talnavicular joint expressed as?
twisting (inverting and everting) of midfoot relative to rearfoot
What does the talonavicular joint consist of?
talus, navicular and spring ligament
What forms the lateral component of transverse tarsal joint?
junction of anterior (distal) surface of calcaneus with proximal surface of cuboid
What does the Relative inflexibility of calcaneocuboid joint provide?
stability to lateral (longitudinal) column of foot
What muscle is the prime supinator of the foot?
tibialis posterior
What rarely moves without the subtalar joint?
transverse tarsal joint
What accounts for most of pronation and supination throughout foot?
Combining motions across subtalar and transverse tarsal joints
What are the two AOR for movement at transverse tarsal joint?
Longitudinal axis: eversion and inversion
Oblique axis: abduction/dorsiflexion and adduction/plantar flexion
What is the amount of pure inversoin/eversion of midfoot?
20-25° of inversion and 10-15° of eversion
What is the primary load-bearing and shock-absorbing structure of foot?
medial longitudinal arch
What are the bones of the medial arch?
calcaneus, talus, navicular, cuneiforms, and associated three medial metatarsals
What nonmuscular structures maintain height and general shape of arch?
plantar fascia, spring ligament (plantar calcaneonavicular), and first tarsometatarsal joint
During standing, what structure maintains height of medial longitudinal arch?
deep plantar fascia
What is pes planus?
flattening or arch
What is pes cavus?
abnormally raised medial longitudinal arch
What motions of the hip are associated with exaggerates pronation of subtalar joint during weight bearing?
Internal rotation, flexion, and adduction
What motions of the knee are associated with exaggerates pronation of subtalar joint during weight bearing?
Increased valgus stress
What motions of the rearfoot are associated with exaggerates pronation of subtalar joint during weight bearing?
Pronation (eversion) with a lowering of medial longitudinal arch
