Ankle And Foot Biomechanics Flashcards
What are the anatomical subdivisions of the foot ?
- the hind foot = talus and calcaneus
- the mid foot = the navicular, cuboids and the 3 cuneiforms
- the fore foot = the metatarsals, proximal, middle and distal phalanx
Which bones compose the talocrural joint ?
- tibia
- fibula
- talus
What is the mortise ?
The talocrural joint, or ankle, is the articulation o the trochlea (dome) and sides o the talus with the rectangular cavity ormed by the distal end of the tibia and both malleoli. The talocrural joint is often referred to as the “mortise,” owing to its resemblance to the wood joint used by carpenters.
What is the role of lateral malleolus ?
It works as an anatomical pulley for the fibularis longus and brevis
Why is the foot slightly externally rotated in natural stance ?
Because the distal end of the tibia is twisted externally
Describe the kinematics of ankle plantar and dorsi flexion
Because the talocrural joint displays a deviation of 10° in the frontal plane :
- dorsiflexion is associated with abduction and eversion
- plantarflexion is associated with adduction and inversion
Dorsiflexion takes place in the sagittal plane along the frontal axis and has 20° ROM
Plantarflexion takes place in the sagittal plane along the frontal axis and has 50° ROM
Is plantarflexion or dorsiflexion more stable ? Why ?
Dorsiflexion is more stable as the talus slides posteriorly and its wider anterior aspect is wedged.
Describe the arthrokinematics of ankle plantar/dorsi flexion in open kinematic chain
Ankle plantar flexion : convex talus glides on concave mortise and the glide is postero anterior
Ankle dorsi flexion l convex talus glides on concave mortise and the glide is antero posterior
Name the lateral collateral ligaments of the talocrural joint, what is their role ?
- the anterior talofibular ligament
- the calcaneofibular ligament
- the posterior talofibular ligament
They prevent excessive inversion
Name the medial ligaments of the talocrural joint, what is their role ?
It’s a group of 4 ligaments composing the “deltoid ligament”
- posterior tibiotalar ligament
- tibiocalcaneal ligament
- tibio navicular ligament
- anterior tibiotalar ligament
They prevent excessive eversion and are stronger than the lateral ligaments of the talocrural joint altogether
Which ligaments limit ankle plantar flexion ?
- anterior talofibular ligament
- anterior tibiotalar ligament
Which ligaments limit ankle dorsiflexion
- posterior tibiotalar ligament
- posterior talofibular ligament
Which ligaments limit external rotation ?
- tibionavicular ligament
- anterior tibiotalar ligament
Which ligament limits internal rotation ?
- anterior talofibular ligament
Name the agonists of ankle plantarflexion
1) gastrocnemius
Origin : condyles of the femur, posterior surface
Insertion : calcaneus via calcaneal tendon
2) soleus
Origin : soleal line; proximal, posterior surface of tibia and posterior aspect of head of fibula
Insertion : calcaneus via calcaneal tendon
Name the synergists of ankle plantarflexion
1) Tibialis posterior
Origin : proximal posterior shaft of tibia and fibula, interosseous membrane
Insertion : all five tarsal bones, and bases of second through fourth metatarsals
2) Fibulris longus
Origin : head of fibula
Insertion : base of first metatarsal and medial cuneiform
3) Fibularis brevis
Origin : distal two third of lateral fibula
Insertion : tuberosity of fifth metatarsal
4) Flexor digitorum longus
Origin : middle posterior surface of the tibia
Insertion : distal phalanges of second through fifth toes
5) Flexor hallucis longus
Origin : middle half of posterior tibia
Insertion : distal phalanx of first toe
Name the antagonists of plantar flexion
1) Tibialis anterior
Origin : lateral condyle of tibia and interosseous membrane
Insertion : medial cuneiform and base of the fifth metatarsal
2) Extensor digitorum longus
Origin : lateral condyle of tibia and interosseous membrane
Insertion : middle and distal phalanges of second through fifth toes
3) extensor hallucis longus
Origin : middle anterior surface of fibula and interosseous membrane
Insertion : distal phalanx of first toe
Name the agonist muscle of ankle dorsiflexion
1) Tibialis anterior
Origin : lateral condyle of tibia and interosseous membrane
Insertion : medial cuneiform and base of the first metatarsal
Name the synergists muscles of ankle dorsiflexion
1) Extensor digitorum longus
Origin: lateral condyle of tibia and interosseous membrane
Insertion : middle and distal phalanges of second through fifth toes
2) Extensor hallucis longus
Origin : middle, anterior surface of fibula and interosseous membrane
Insertion : distal phalanx of first toe
Name the antagonists of ankle dorsiflexion
1) gastrocnemius
2) soleus
3) Tibialis posterior
4) fibularis longus
5) fibularis brevis
6) flexor digitorum longus
7) flexor hallucis longus
Name the articulations forming the subtalar joint
- posterior facets of talus and calcaneus
- anterior facets of talus and calcaneus
- lateral facets of talus and calcaneus