Lecture 10 - Ankle Flashcards
Divisions of the foot
Hindfoot, Midfoot, Forefoot
Hindfoot
talus
calcaneus
midfoot
navicular
cuboid
cuneiforms
forefoot
metatarsals
phalanges
Superior tibiofibular joint
synovial plane joint with a capsule
inferior tibiofibular joint
Syndesmosis
- posterior tibiofibular ligament
- anterior tibiofibular ligament
- crural tibiofibular interosseous ligament
Talotibial Joint (talocrural)
ankle
most congruent joint in the body
Mortise joint and tendon
synovial hinge joint
Axis: toe out stance (normal tibial torsion)
Pathological (external/internal tibial torsion)
Dorsiflexion
increased toe out
plantarflexion
decreased toe out
Most ankle joint movements occur in the ___ plane.
sagittal
Medial Collateral Ligament
aka- deltoid Components -tibionavicular -tibiocalcanean -anterior tibiotalar -posterior tibiotalar
Lateral Collateral Ligament
weakest of the collaterals Components -anterior talofibular -posterior talofibular -calcaneofibular
Talocalcaneal Joint (subtalar)
Very Stable Uniaxial, triplanar Three Surfaces: Posterior (concave facet on talus with convex facet on calcaneus) Anterior (Convex facets on body and neck of talus; concave facets on calcaneus) Tarsal Tunnel -nonsynovial -ligament=talocalcaneal
Talocalcaneal Joint Movements:
Inversion: -adduction -supination -plantarflexion Eversion -abduction -pronation -dorsiflexion
Ligaments of Talocalcaneal Joint
interosseous talocalcaneal
Posterior and lateral talocalcaneal ligaments
Talocalcaneonavicular Joint
•Composite joint: •Talocalcaneal joint + •Talonavicular joint
- Movements:
- Inversion (close packed)
- Eversion
- Ligament:
- Calcaneonavicular (spring) ligament:
- From sustentaculum tali to inferior navicular
- Continuous medially with deltoid ligament
- Continuous laterally with medial band of bifurcate ligament
- Helps to maintain medial longitudinal arch
Calcaneocuboid Joint
Articulating bones:
•Calcaneus
•Cuboid
Movements:
•Triplanar
Ligament:
•Plantar calcaneocuboid (short plantar)
•Long plantar: Most important
Transverse tarsal joint
Intertarsal Joint
Composite joint:
•Talonavicular+ Calcaneocuboid
Function:
•Traditional link between hindfoot and forefoot
•Adds to inversion/eversion range
•Compensates forefoot for hindfoot eversion
•Keeps distal foot inverted with lateral surface in contact with ground while hindfoot is everted
•Compensation between hindfoot and forefoot not possible when hindfoot is inverted.
Other arch support structures
- Shapes of bones
* Peroneus longus
Plantar Arches: Support Ligaments
Plantar calcaneonavicular (spring): •Primary support for medial longitudinal arch Long plantar: •Primary support for lateral longitudinal arch
- Plantar aponeurosis
- Plantar calcaneocuboid (short plantar)
- Marginal abductors
Plantar Arches
Longitudinal:
•Medial
•Lateral
Pathologies:
•Pes cavus
•Pes planus
Superior/inferior extensor retinacula
•Localized thickenings of anterior crural fascia
- Bind down tendons of:
- Tibialis anterior
- Extensor hallucis longus
- Extensor digitorum longus
- Peroneus tertius
- Covers: •Deep peroneal (fibular) nerve •Anterior tibial artery
- Inferior retinaculum is “Y” shaped
Flexor Retinaculum
Localized medial thickening of crural fascia
Binds down tendons of:
•Flexor hallucis longus
•Flexor digitorum longus
•Tibialis posterior
Covers:
•Tibial nerve
•Posterior tibial artery
Peroneal (fibular) retinaculum
Localized medial thickening of lateral deep fascia
Binds down tendons of:
•Peroneus (fibularis) longus
•Peroneus (fibularis) brevis
Retinacula
Superficial fascial structures that bind tendons and muscles down against the foot to prevent excessive free movement
Plantar Aponeurosis
Fascial sheath from the calcaneus that divides into 5 bands that enclose the flexor tendons going to the toes
Functions as a superficial ligament
Tightens and causes plantar fasciitis
Deltoid Ligaments
Strong triangular band originating from medial malleolus
Rarely injured alone – typically associated with fracture of distal fibula
Medial Longitudinal Arch
- Calcaneus, talus, navicular, 3 cuneiforms, medial 3 metatarsals
- Highest and most important arch
- Supported by tendon of fibularis longus m.
Lateral Longitudinal Arch
Calcaneus, cuboid, lateral 2 metatarsals
Transverse Arch
- Cuboid, 3 cuneiforms, bases of all 5 metatarsals
* Supported by tendons of fibularis longus and tibialis posterior ms.
Functions of Foot Arches
- Absorb shock during weight-bearing
* Make foot adaptable to surface and weight changes
Pes Planus
flat foot
Normal before 3 yo d/t subcutaneous fat pad (goes away with age)
3 types of Pes Planus: Flexible -> loose or degenerated intrinsic ligaments (common in childhood but usually resolves with age)
Rigid -> typically d/t bone deformity
Acquired -> secondary to dysfunction of tibialis posterior from trauma, age, or denervation
Dynamic Arch Supports
- Intrinsic foot muscles
* Tendons of leg muscles extending foot
Passive Arch Supports
- Shapes of bones
- Plantar aponeurosis
- Long plantar lig. maintains longitudinal arches
- Short plantar lig. (plantar calcaneocuboid) maintains longitudinal arches
- Spring lig. (plantar calcaneonavicular) supports head of talus, helps transfer weight from talus to rest of foot
