Lecture #6 (Ankle & Foot) Flashcards
What is the function of the ankle?
Unites the foot and leg
How many bones and joints are there in the ankle?
28 bones
25 joints
What are the three regions of the foot?
Forefoot, midfoot, and hindfoot
What is causes the foot position of slight external rotation when standing?
Tibial torsion
What is the normal tibial torsion?
Rotation of the tibial that occurs naturally laterally at the distal end of 20-40 degrees
What percentage of a force/load is placed on the fibula? Can this increase or decrease?
6-7%
**It can increase slightly during dorsiflexion & eversion
What is the ankle mortise?
Distal tibiofibular joint
Once the force of the body’s weight hits the talocrural joint, what happens?
50% is taken by the calcaneous and 50% is taken by the foot
What type of joint is the distal tibiofibular joint?
Syndesmosis (it has an interosseous membrane)
What are the two joints of the ankle?
Subtalar and tibio-talar (talocrural) joints
What is the open pack position for the talocrural joint? The closed packed?
Open= 10 degrees plantar flexion Closed= full dorsiflexion
What is the open packed position for the subtalar joint?
Subtalar neutral
What makes up the talocrural joint?
The articulation of the talus with the tibia and fibula (makes a mortise)
What type of joint is the talocrural joint?
Modified hinge joint
What is the orientation of the axis for the talocrural joint?
Oblique…18 degrees in the transverse plane laterally and 14 degrees in the frontal plane laterally…so it runs from superior/medial/anterior to inferior/lateral/posterior
What are the primary motions of the talocrural joint?
Plantar flexion and dorsiflexion
In what plane does dorsiflexion and plantar flexion occur in? Axis?
Sagittal plane
Horizontal axis
In what plane does ankle adduction and abduction occur in? Axis?
Transverse plane
Vertical axis
In what plane does ankle inversion and eversion occur in? Axis?
Frontal plane
A/P axis
What does dorsiflexion do to the foot?
Brings it up, slightly laterally, and longitudinally out
What does plantar flexion do the foot?
Brings it down, slightly medially, and longitudinally in
True or false:
The talus is broader anteriorly and narrower posteriorly.T
True…this is important because high ankle sprains occur during dorsiflexion because the broader talus is locked in between the malleoli. (Normal ankle sprains occur with the foot in some plantar flexion because there is a gap between the talus and the malleloi).
How prevalent are high ankle sprains?
1-11% of ankle sprains
If you widen the space of the tibiatalar joint by 1 mm, how much does it decrease the joint contact area?
By 42%
What does abduction and adduction at the foot mimick?
Internal and external rotation
True or false:
The talus is considered both part of the ankle and the foot.
True
True or false:
70% of the talus is covered with cartilage. Why or why not?
True because the talus is a part of three joints (talocrural, subtalar, and transverse tarsal) and so it is covered in a lot of cartilage
Where is the joint capsule of the ankle the strongest? Why?
Medially because of the deltoid ligament
What are the medial ligaments of the talocrural joint?
Deltoid (4 parts…tibionavicular, tibiocalcaneal, ant. tibiotalar and posterior tibiotalar)
Spring ligament
Where does the spring ligament run? What does it help do?
Sustentaculum tali to the navicular…helps to support the longitudinal arch
What are the three bands of the lateral ligaments of the talocrural joint? What other structure is found on the lateral ankle?
1-posterior talofibular
2-anterior talofibular
3-calcaneofibular
Peroneal retinaculum (helps hold peroneals under lateral malleolus)
What is the subtalar joint?
The joint between the talus and the calcaneus
What are the motions of the subtalar joint? Their planes and axes?
Inversion/Eversion= frontal plane & A/P axis Calcaneal abduction (valgus)/adduction(varus)= transverse plane & vertical axis
What is the orientation of the axis of the subtalar joint?
42 degrees from the frontal plane…it’s almost halfway between the transverse and frontal planes
What is the ROM for ankle eversion? Inversion?
Eversion=5-10 degrees
Inversioin= 20-30 degrees
Does the talus remain relatively free or fixed during calcaneal motion in the open chain?
Free
What constitutes pronation of the foot?
Calcaneal eversion (subtalar) Calcaneal abduction (subtalar) Talocrural dorsiflexion **Usually forefoot supination
What constitues supination of the foot?
Calcaneal inversion (subtalar)
Calcaneal adduction (subtalar)
Talocrural plantar flexion
**Usually forefoot pronation
What occurs with pronation of the foot that causes tibial internal rotation (rolling in of the foot)?
Calcaneal valgus
What occurs with supination of the foot that causes tibial external rotation (rolling out of the foot)?
Calcaneal varus
Between calcaneal varus and valgus, which one lengthens the leg and which one shortens the leg?
Varus= longer Valgus= shorter
From what point do we assess or measure the ROM of the subtalar joint?
Subtalar neutral
True or false:
During subtalar motion, the calcaneus will invert twice as much as it will evert.
True…we tend to invert more than we evert
What are the two arches of the foot?
Longitudinal= from the heel to the heads of the metatarsals Transverse= the concavity from side to side (anterior tarsal bones and metatarsals)
What is the keystone of the transverse arch? The longitudinal arch?
Transverse= 2nd cuneiform Longitudinal= talus (and some navicular)
What two structures help to maintain the arch of the foot?
Spring ligament and plantar fascia
What is the transverse tarsal joint?
The division between the rearfoot and the forefoot
What does the transverse tarsal joint do?
Adds to ROM of the foot during pronation and supination because it locks and unlocks the foot
What is the problem with having a high arch?
There is poor shock absorption
What muscles work together to produce dorsiflexion? (x4)
Tibialis anterior
Peroneus tertius
Extensor digitorum longus
Extensor hallucis longus
What muscles work together to produce plantar flexion? (x3+5)
Gastroc
Soleus
Plantaris
(also possibly tibialis posterior, peroneus brevis & longus, flexor digitorum longus, and flexor hallucis longus)
What muscles work together to produce inverion/supination? (x5)
Tibialis anterior (when foot is dorsiflexed)/ Tibialis posterior (when the foot is plantar flexed) Flexor hallucis longus Flexor digitorum longus Gastroc/Soleus (could help in pronated people0
What muscles work together to produce eversion/pronation?(x4)
Peroneus longus
Peroneus brevis
Peroneus teritus
Extensor digitorum longus
What muscles work together to flex the toes?
Flexor digitorum longus
Flexor hallucis longus
Intrinsic muscles
What muscles work together to extend the toes?
Extensor digitorum longus
Extensor hallucis longus
Intrinsics
What are some pathologies associated with supinated feet? (x7)
Callousing Bunions Stress fractures Heel spurs/plantar fascitis ITB syndrome Patellofemoral syndromes Turf toe
What are some pathologies associated with pronated feet? (x5)
Callousing Hallux valgus Heel spurs/plantar fasciatis Shin splints Patellofemoral syndromes
