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Non Muscular Anatomy
Bones
Inferior Tibia
 Prominent medial malleolus which is continuous with the medial shaft
 Inferior surface is smooth for articulation with the talus
 Inferior surface continues medial with the malleolar articular surface
 Inferior surface turns upward laterally for articulation with the fibula
 Anterior surface of smooth
 Posterior surface is coarse and grooved by tendons
Inferior Fibula
 Flattened medially and laterally
 Malleolar fossa found posteriorly
 Articulates with the talus medially
Calcaneus
 Inferior to the talus
 Forms the heel
 Strongly bound to all the tarsal bones by ligaments
 Calcaneal tuberosity present posteriorly for Achilles tendon insertion
 Sustentaculum tali present medially and superiorly
o Support and articulates with the talus superiorly
o Provides anchors for ligaments
o Helps flexor hallucis longus, tibialis posterior and flexor digitorum longus pass into
the foot
Talus
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Superior to calcaneus
Transmits body weight from tibia to calcaneus and navicular
Split into body and head
Body
o Wedge shaped body being wider anteriorly
o In between the fibular and tibia
o Convex upper surface
Head
o Inferior surface articulates with the sustentaculum tali of the calcaneus
o Anterior surface articulates with the navicular
Navicular
 Found anteriorly to the head of the talus
 Large tuberosity found inferomedially
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Anterior surface divided into 3 triangular areas
Forms articular surface for 3 cuneiform bones
Cuboid
 Has 6 surfaces
 Makes up the transverse arch of the foot with the 3 cuneiform bones
 Location
o Lateral to lateral cuneiform
o Anterior to the calcaneus
o Posterior to 4th and 5th metatarsals
Cuneiform
 3 different wedge shaped bones
 Makes up the transverse arch of the foot with the cuboid
o Medial Cuneiform
 Articulates with the navicular posteriorly
 Articulates with the 1st metatarsal anteriorly
 Articulates with the 2nd metatarsal and Intermediate cuneiform laterally
o Intermediate Cuneiform
 Articulates with the medial cuneiform medially
 Articulates with the lateral cuneiform laterally
 Articulates with the navicular posteriorly
 Articulates with the 2nd metatarsal anteriorly
o Lateral Cuneiform
 Articulates with the cuboid laterally
 Articulates with the intermediate cuneiform medially
 Articulates with the navicular posteriorly
 Articulates with the 2nd and 3rd metatarsal anteriorly
Metatarsals
 5 in each foot
 All have a shaft, a head distally and a base proximally
 Bases articulate with the tarsal bones
 Head articulates with the proximal phalanx
o 1st metatarsal
 shortest and thickest
 Articulates with medial cuneiform posteriorly
 Articulates with the 2nd metatarsal laterally
o 2nd metatarsal
 Longest
 Articulates with the intermediate cuneiform posteriorly
 Articulates with the medial cuneiform and 1st metatarsal medially
 Articulates with the 3rd metatarsal and lateral cuneiform laterally
o 3rd metatarsal
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 Articulates with the lateral cuneiform posteriorly
 Articulates with the 2nd metatarsal medially
 Articulates with the 4th metatarsal laterally
4th metatarsal
 Articulates with the cuboid posteriorly
 Articulates with the 3rd metatarsal medially
 Articulates with the 5th metatarsal laterally
5th metatarsal
 Articulates with the cuboid posteriorly
 Articulates with the 4th metatarsal medially
 large tubercle that projects posterolaterally from its base
Phalanges
 2 phalanges in the great toe
 3 phalanges in the other toes
 Long bones with a shaft and two extremities
 Head of the distal phalanx is flattened on its dorsum and has no articular area
Joints
Distal Tibiofibular Joint
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Fibrous joint (syndesmosis)
Distal tibia and fibula do not come into contact with each other
Separated by fibroadipose tissue
Joint Orientation
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Convex surface of the medial distal fibula
Concave surface of the lateral distal tibia
Ligamentous Anatomy
Anterior tibiofibular ligament
 Fibular notch of tibia to lateral malleolus of fibula
Posterior tibiofibular ligament
 Fibular notch of tibia to lateral malleolus of fibula
 Thicker and broader than the anterior tibiofibular ligament
Transverse tibiofibular ligament
 Deep to posterior tibiofibular ligament
 Thick and strong
 From inferior border of tibia to malleolar fossa of fibula
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Descends below bone posteriorly and forms part of the articular surface for the posterior
aspect of the talus
Joint Capsule and Synovial Membrane
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Interosseous membrane
o fibrous joint between the tibia and fibula
o Does not reach as far as the superior tibiofibular joint
o Divides the anterior and posterior compartment of the leg
Synovial-lined recess of the ankle joint cavity extends upwards between the tibia and fibula
Arthrokinematics
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Dorsiflexion
o Anterior talus forced into posterior part of tibiofibular socket
o Talus larger than tibiofibular socket
o Tibiofibular joint separates
 Increases tension in interosseous and transverse ligaments
 Fibula rotates axially
 Lateral malleolus moves laterally and superiorly
Plantarflexion
o Posterior talus moves into anterior part of the tibiofibular socket
o Posterior talus smaller than tibiofibular socket
o Tibiofibular joint comes together
 Lateral malleolus moves medially and inferiorly
 Fibula rotates axially (opposite direction to dorsiflexion)
Talocrural Joint
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Synovial hinge joint between tibia, fibula and talus
Allows plantarflexion and dorsiflexion
Joint Orientation
Tibia/Fibula
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Concave anteroposteriorly
Convex transversely
Talus
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Convex anteroposteriorly
Concave transversely
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Ligamentous Anatomy
Medially
Deltoid Ligament
 From tibial malleolus to navicular bone anteriorly and talus/calcaneus distally/posteriorly
 Very strong ligament
 Valgus force may avulse tibial malleolus before tearing deltoid ligament
 Thick medial ligament made up of several bands
o (Deep Layer) Anterior tibiotalar band
 Medial malleolus to anteromedial talus
o (Deep Layer) Posterior tibiotalar band
 Passes backwards and laterally to the inner side of the talus medial to the
groove for flexor hallucis longus
o (Superficial Layer) Tibionavicular band
 Passes forward to the tuberosity of the navicular bone and merges with the
plantar calcaneonavicular ligament
o (Superficial Layer) Tibiocalcaneal band
 Insert to the whole length of the sustentaculum tali of the calcaneus
 Primary function is to control medial distraction and calcaneal eversion
 Anterior parts limit plantarflexion
 Posterior parts limit dorsiflexion
Plantar calcaneonavicular (spring) ligament
 Short thick wide ligament
 Connects the anterior sustentaculum tali of the calcaneus to the plantar surface of the
navicular bone
 Supported by tibialis posterior
 Blends with the deltoid ligament
 Helps to support medial longitudinal arch
Laterally
 Not as strong as medially
 Made up of 3 ligaments controlling varus stress and calcaneal inversion
Anterior talofibular ligament
 Anterior margin of the fibular malleolus then passes medially and anterior to the lateral talus
 Resists anterior translation of the foot in relation to the shin
 Resists plantarflexion
 Resists talus internal rotation
 Commonly injured with lateral inversion ankle sprains
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Posterior talofibular ligament
 Almost horizontal from malleolar fossa of the lateral malleolus to the posterior surface of
the talus
 Resists dorsiflexion
Calcaneofibular ligament
 Narrow cord
 Lateral malleolus downwards and slightly backwards to the lateral surface of the calcaneus
 Covered by the tendons of peroneus longus and brevis
 Resists adduction
Joint Capsule and Synovial Membrane
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Fibrous capsule
o completely surrounds the joint
o attaches to the articular margins of the tibia and fibula superiorly and talus inferiorly
o thickened medially and laterally by ligaments
Synovial Membrane
o Lines the capsule
Arthrokinematics
Capsular Pattern
Resting Position
Close Packed
Position
End Feel
Talocrural Joint
Plantarflexion then dorsiflexion
Mid inversion/eversion and 10 plantar flexion
End range dorsiflexion
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Movements
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Plantarflexion
o FIRM
 Tension in anterior capsule, anterior portion of
deltoid and anterior talofibular ligament, anterior
tibial muscle and long extensors of the toes
Dorsiflexion
o FIRM
 Tension in posterior capsule, Achilles tendon,
posterior portion of deltoid and calcaneofibular
ligament and posterior talofibular ligament
Non Weight Bearing
o Dorsiflexion
 Fibula moves laterally and superiorly
 Talus rolls anteriorly and glides posteriorly
o Plantarflexion
 Fibula moves medially and inferiorly
 Talus rolls posteriorly and glides anteriorly
Weight Bearing
o Dorsiflexion
 Fibula moves laterally and superiorly
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Distal tibia and fibula roll anteriorly and glide
anteriorly
 More movement through tibia
 therefore internal rotation of tibia occurs
Plantarflexion (talus still moves on tibia/fibula)
 Fibula moves posteriorly
 External rotation of the tibia
 Anterior glide of the talus
Subtalar Joint
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Synovial joint
Allows inversion and eversion of the foot
Space between the talus and calcaneus is the sinus tarsi space
This space is filled with connective and adipose tissue richly innervated with
mechanoreceptors and free nerve endings
Joint Orientation
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Concave surface of the talus
Convex surface of the calcaneus
Ligamentous Anatomy
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All ligaments provide subtalar stability with calcaneal parts of medial and lateral talocrural
ligaments
Ligaments can be split into
o Extrinsic
 Calcaneofibular ligament
 Deltoid ligament
o Intrinsic
 Talocalaneal ligament
 Interosseous ligament
 Cervical ligament
Interosseous (talocalcaneal) ligament
 Thick strong band
 Main subtalar ligament providing most stability
 Runs through the sinus tarsi
 Made up of an anterior and posterior band
Cervical Ligament
 Inside the sinus tarsi
 Strong ligament providing stability
Talocalcaneal ligament
 Made up of anterior, posterior, lateral and medial components
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Joint Capsule and Synovial Membrane
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Thin, loose, fibrous capsule surrounds the joint
Thicker medially, posteriorly and laterally
o Forms medial, posterior and lateral talocalcaneal ligaments
Capsule is lined with a synovial membrane
Arthrokinematics
Capsular Pattern
Resting Position
Close Packed
Position
End Feel
Subtalar Joint
Varus more limited than Valgus
Mid inversion/eversion and 10 plantar flexion
Full Inversion
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Inversion
o FIRM
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Eversion
o FIRM
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Tension in lateral joint capsule and lateral ligament
Tension in joint capsule, deltoid ligament and
posterior tibialis muscle
Movements
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Open Chain
o Produced by calcaneus moving on fixed talus and leg
o Pronation
 Dorsiflexion, abducted and eversion
o Supination
 Plantarflexion, adduction and inversion
Closed Chain
o Calcaneal movement transverse and sagittal movement blocked by ground
o Calcaneal movement in frontal plane remains the same
o Pronation
 Calcaneus eversion, talar plantar flexion and adduction + tibia internal rotation
 Gives a wider, flatter foot
o Supination
 Calcaneus inversion, talar dorsiflexion and abduction + tibial external rotation
 Gives a narrower, higher foot
Other Structures
Plantar Fascia
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Thick aponeurosis
Calcaneus tuberosity to the heads of the metatarsals
Longitudinally orientated collagen fibres
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3 distinct components
o Medial
o Central
o Lateral
Continuous with the Achilles tendon
Function
Support the Body Weight
 Acts as a truss
 Weight goes through talus
 Creates a ground reaction force through up through metatarsals and calcaneus
 The bones in the foot are compressed between ground reaction force and body weight
 Plantar fascia acts as a tie cord between the forefoot and the calcaneus to prevent the arch
from collapsing
Windlass Mechanism during Gait
 Windlass mechanism pulls the two ends of the foot together
 Compressing the bones and raising the height of the arch
 Stabilising the foot
 Increases its ability to act as a lever
 Toes dorsiflex, wrapping plantar fascia around metatarsal heads
 Plantar fascia pulls tight, compressing and supinating
 The arch rises and foot shortens and becomes rigid
Bursae
Retrocalcaneal Bursa
 Located between the Achilles and the calcaneus
Subcutaneous Calcaneal Bursa
 Located between the skin and posterior aspect of the Achilles tendon
Fat Pad
Subcalcaneal fat pad
 Underneath the calcaneus
 Can be a source of pain
Arches
Medial Longitudinal Arch
 Higher than the lateral arch
 Made up of the calcaneus, talus, navicular, 3 cuneiforms, first, second and third metatarsals
 Peaks at the superior articular surface of the talus
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Weakest at the joint talonavicular joint
o Supported by the plantar calcaneonavicular ligament (spring ligament)
o Elastic and aids to restore arch to normal position under deformation
Supported by tibialis posterior, plantar aponeurosis and small muscles in sole of foot
Lateral Longitudinal Arch
 Made up of the calcaneus, cuboid and fourth and fifth metatarsals
 Strong arch supported by long plantar and plantar calcaneocuboid ligaments
 Supported by extensor tendons and short muscles of little toe
Transverse Arch
 Made up of the cuboid bone, 3 cuneiform and the base of the metatarsals
 Supported by tibialis posterior, tibialis anterior, peroneal longus and plantar fascia
Structural Abnormalities
Calcaneal (Rearfoot) Varus
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Calcaneus inverts
Foot is more supinated at heel strike
Lack of eversion at the subtalar joint
Uncompensated
 Calcaneus inverts and navicular raised = supinated
 Causes plantarflexion 1st ray and a varus tibia
Compensated
 Calcaneus vertical and navicular collapses = pronated
Gait Changes
 Pronation occurs at heel strike and continues until heel rise
 After heel rise the foot supinates for normal propulsion
Forefoot Varus
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Causes many problems
Forefoot inverted (big toe higher than 5th toe)
Subtalar joint and calcaneus are in neutral
Causes pronation
Uncompensated
 uncommon
 Calcaneus vertical and navicular raised = supination
Compensated
 Calcaneal valgus (eversion) and navicular collapse and forefoot abduction = pronation
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Gait Changes
 Pronation occurs at heel strike and continues through stances phase
 Propulsion occurs with a pronated foot
Forefoot Valgus
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More rigid and supinated feet
High risk of inversion ankle sprains
Forefoot is everted while calcaneus and subtalr joint in neutral
Medial tarsal below the calcaneus
Can be just the 1st ray plantarflexed or all the toes
Uncompensated
 Very uncommon
Compensated
 Calcaneal varus (inverted) and navicular raised = supinated
Gait Changes
 Excessive supination occurs after heel strike due to premature loading of the forefoot
 Pronation is insufficient but may occur at end of stance phase
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