Transcript Non Muscular Anatomy

Non Muscular Anatomy
Foot and Ankle
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
• Support and articulates with the talus
superiorly
• Provides anchors for ligaments
• Helps flexor hallucis longus, tibialis
posterior and flexor digitorum longus pass
into the foot
Talus
• Superior to calcaneus
• Transmits body weight from tibia to
calcaneus and navicular
• Split into body and head
• Body
• Wedge shaped body being wider
anteriorly
• In between the fibular and tibia
• Convex upper surface
• Head
• Inferior surface articulates with the
sustentaculum tali of the calcaneus
• Anterior surface articulates with the
navicular
Navicular
• Found anteriorly to the head of
the talus
• Large tuberosity found
inferomedially
• 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
• Lateral to lateral cuneiform
• Anterior to the calcaneus
• Posterior to 4th and 5th metatarsals
Cuneiform - Medial
• 3 different wedge shaped bones
• Makes up the transverse arch of
the foot with the cuboid
• Medial Cuneiform
• Articulates with the navicular
posteriorly
• Articulates with the 1st metatarsal
anteriorly
• Articulates with the 2nd metatarsal
and Intermediate cuneiform laterally
Cuneiform - Intermediate
• 3 different wedge shaped bones
• Makes up the transverse arch of
the foot with the cuboid
• 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
Cuneiform - Lateral
• 3 different wedge shaped bones
• Makes up the transverse arch of
the foot with the cuboid
• 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
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
Distal Tibiofibular Joint
Distal Tibiofibular Joint
• Fibrous joint (syndesmosis)
• Distal tibia and fibula do not
come into contact with each
other
• Separated by fibroadipose tissue
Distal Tibiofibular Joint - Ligaments
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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
Descends below bone posteriorly and forms part of
the articular surface for the posterior aspect of the
talus
Distal Tibiofibular Joint – Joint Capsule and
Synovial Membrane
• Interosseous membrane
• fibrous joint between the tibia and
fibula
• Does not reach as far as the
superior tibiofibular joint
• Divides the anterior and posterior
compartment of the leg
• Synovial-lined recess of the
ankle joint cavity extends
upwards between the tibia and
fibula
Distal Tibiofibular Joint – Arthrokinematics
• Plantarflexion
• Posterior talus moves into anterior
part of the tibiofibular socket
• Posterior talus smaller than
tibiofibular socket
• Tibiofibular joint comes together
• Lateral malleolus moves medially
and inferiorly
• Fibula rotates axially (opposite
direction to dorsiflexion)
Distal Tibiofibular Joint – Arthrokinematics
• Dorsiflexion
• Anterior talus forced into posterior
part of tibiofibular socket
• Talus larger than tibiofibular
socket
• Tibiofibular joint separates
• Increases tension in interosseous
and transverse ligaments
• Fibula rotates axially
• Lateral malleolus moves laterally and
superiorly
Talocrural Joint
Talocrural Joint
• Synovial hinge joint between
tibia, fibula and talus
• Allows plantarflexion and
dorsiflexion
Talocrural Joint - Ligaments
• 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
• Primary function is to control
medial distraction and calcaneal
eversion
• Anterior parts limit plantarflexion
• Posterior parts limit dorsiflexion
Talocrural Joint - Ligaments
• 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
Talocrural Joint - Ligaments
• 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
• 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
Talocrural Joint – Joint Capsule and Synovial
Membrane
• Fibrous capsule
• completely surrounds the joint
• attaches to the articular margins
of the tibia and fibula superiorly
and talus inferiorly
• thickened medially and laterally by
ligaments
• Synovial Membrane
• Lines the capsule
Talocrural Joint – Arthrokinematics
Subtalar Joint
Subtalar Joint
• 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
Subtalar Joint - Ligaments
• All ligaments provide subtalar
stability with calcaneal parts of
medial and lateral talocrural
ligaments
• Ligaments can be split into
• Extrinsic
• Calcaneofibular ligament
• Deltoid ligament
• Intrinsic
• Talocalaneal ligament
• Interosseous ligament
• Cervical ligament
Subtalar Joint - Ligaments
• 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
Subtalar Joint - Ligaments
• 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
Subtalar Joint - Movements
• Calcaneal movement transverse and
sagittal movement blocked by ground
• Calcaneal movement in frontal plane
remains the same
• Pronation
• Calcaneus eversion, talar plantar flexion
and adduction + tibia internal rotation
• Gives a wider, flatter foot
• Supination
• Calcaneus inversion, talar dorsiflexion
and abduction + tibial external rotation
• Gives a narrower, higher foot
Subtalar Joint - Movements
• Produced by calcaneus moving
on fixed talus and leg
• Pronation
• Dorsiflexion, abducted and
eversion
• Supination
• Plantarflexion, adduction and
inversion
Other Structures
Plantar Fascia
• Thick aponeurosis
• Calcaneus tuberosity to the heads
of the metatarsals
• Longitudinally orientated collagen
fibres
• 3 distinct components
• Medial
• Central
• Lateral
• Continuous with the Achilles
tendon
Plantar Fascia – Supporting 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
Plantar Fascia – Windlass Mechanism
• 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
• Weakest at the joint talonavicular joint
• Supported by the plantar calcaneonavicular
ligament (spring ligament)
• Elastic and aids to restore arch to normal
position under deformation
• Supported by tibialis posterior, plantar
aponeurosis and small muscles in sole of
foot
Arches
• 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
Arches
• 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
• Gait Changes
• Pronation occurs at heel strike and continues through stances phase
• Propulsion occurs with a pronated foot
Forefoot Varus
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
Forefoot Valgus