anatomy and bio mechanics

1. THE ANKLE
AND FOOT COMPLEX
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Recommended book
Joint structure and function
Pamela K. Levangie

2. INTRODUCTION
• permit both stability and mobility.
• Foot is able to Sustain large weight bearing stress.
• Foot is divided into three segments:
• Hind foot
• Midfoot
• forefoot
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3. BONES OF THE FOOT
• The bones of the foot include
• Tarsals (7)
• Calcaneus
• Talus
• Navicular
• Cuboid
• Cuneiforms (3)
• Metatarsals
• Phalanges
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4. MOTIONS AT ANKLE JOINT
• Dorsiflexion / Plantar flexion
• Eversion / Inversion
• Abduction : accompany eversion
• Adduction: accompany inversion
• “Composite” motions that have components of
each of the cardinal motions.
• Supination
• Combination of plantar flexion, inversion, and
adduction.
• Pronation
• Combination of dorsiflexion, eversion, and abduction
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5. MOTION OF THE ANKLE/FOOT
• Valgus (Calcaneovalgus)
• Movement of the distal segment away from the midline
• Increase in the medial angle between the calcaneus and
posterior leg.
• Varus (Calcaneovarus)
• Movement of the distal segment towards the midline
• Decrease in the medial angle between the calcaneus and
posterior leg.
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6. TALOCRURAL JOINT
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7. ANKLE JOINT
• Refers to as talocrural joint
• Synovial hinge joint with joint capsule and ligaments
• Articulation :
• Proximally :
• Between distal tibia and of the tibial and fibular malleoli
• Distally :
• Body of talus
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8. PROXIMAL ARTICULAR SURFACES
• The structure of the distal tibia and the malleoli which is referred to as a
mortise.
• The mortise of the ankle is adjustable:
• Relying on the distal tibiofibular joints
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9. Axis
• In neutral position of the ankle joint :
• The joint axis passes through the fibular malleoli
and the body of talus and through the tibial
malleolus, the axis of the ankle is inclined down on
the lateral side
• Downward inclination to Average 14o from
transverse plane.
• Ankle axis rotated, on average, 23o from the frontal
plane.
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Lateral
Medial

10. LIGAMENTS
• MEDIAL COLLATERAL LIGAMENT (MCL)
• Deltoid ligament
• Tibionavicular ligament (anteriorly)
• Tibiocalcaneal ligament (middle)
• Posterior tibiotalar ligament (posteriorly)
• Anterior tibiotalar ligament (deep)
• Functions
• Strengthens the medial side of the ankle joint
• Control valgus stresses on the ankle joint
• Helps to maintain the medial longitudinal arch.
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11. LIGAMENTS
• LATERAL COLLATERAL LIGAMENT (LCL)
• Anterior talofibular ligament
• Posterior talofibular ligament
• Calcaneofibular ligament
• Functions
• Strengthen lateral side of ankle joint
• control varus stresses on the ankle joint
• Help to maintain lateral longitudinal arch
• The components of the LCL are weaker and more susceptible to injury than
are those of the MCL
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12. ANKLE JOINT MOTION
• 20o dorsiflexion
• Close-packed and Stable position
• 50o plantar flexion.
• Loose packed and Less stable position
Higher incidence of ankle sprains in plantar flexion and than dorsi flexion
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13. ARTHROKINEMATIC
• The concave articulating surface is the mortise articulate with the convex
articulating surface is the body of the talus.
• With physiological motions of the foot, the articulating surface of the talus
slides in the opposite direction
• Dorsi flexion : Rolling anteriorly , sliding posteriorly
• Planter flexion : rolling posteriorly , sliding anteriorly
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14. SABTALAR JOINT/ TALOCALCANEAL
JOINT
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15. SUBTALAR JOINT STRUCTURE
• Talocalcaneal, or subtalar, joint is a composite joint formed between the talus
superiorly and the calcaneus inferiorly.
• stable joint that rarely dislocates
• Posterior articulation is the largest
• Has its own capsule
• Anterior and medial articulations
• Share a capsule with the talonavicular joint.
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16. LIGAMENTS
• Calcaneofibular ligament
• Lateral talo calcaneal ligament
• Cervical ligament
• Interosseous talocalcaneal ligament
• Collateral ligaments
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17. SUBTALAR JOINT FUNCTION
• Supination and pronation:
• Motion of the talus on the calcaneus
• complex twisting or screw like motion
• Triplanar motion of the talus around a single oblique joint axis, producing the
motion of supination/pronation
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18. Axis
• Supination / pronation
• (A) inclined up from the transverse plane approximately 42o
• (B) inclined medially from an A-P axis approximately 16o.
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19. ARTHROKINEMATIC
• Motion of Calcaneus:
• Supination with inversion : roll medially , slide laterally
• Pronation with eversion : roll laterally , slide medially
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20. PLANTAR ARCHES
• Longitudinal arch
• Medial longitudinal arch
• Lateral longitudinal arch
• Transverse arch
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21. MEDIAL LONGITUDINAL ARCH
• Largest & Highest
• Composed of Calcaneus, Talus, Navicular, Medial Cuneiform and First
Metatarsal
• Talus is the Keystone of the arch
• All weight transmitted from body to heel and forefoot must pass through
Talus
• Arch depresses during weight-bearing,
• Then recoils when the weight is removed
• Normally, it never flattens or touches the ground.
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22. LATERAL LONGITUDINAL ARCH
• Lower than Medial Longitudinal Arch
• Composed of Calcaneus, Cuboid and Fifth Metatarsals
• Cuboid is the Keystone of the arch
• It normally rests on the ground during weight-bearing
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23. Transverse Arch
• Concave from medial to lateral
• Composed of Three Cuneiforms and Cuboid.
• Middle Cuneiform is the keystone of this arch
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Frontal view
At the level of the middle
of the metatarsals

24. Weight-bearing Surfaces And Support
• Main weight-bearing surfaces are:
• Structures of the bones provide stability to arches,
• But additional support is provided by Ligaments and Muscles
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25. Loads on the foot
• Increase with Body weight and Gait speed
• Load is evenly distributed over the foot, during weight bearing
• 50% of body weight is distributed through subtalar joint to calcaneus
bone
• Remaining 50% is transmitted across metatarsal heads
• 1st MT head sustains twice the load, than other MT heads

26. THANKYOU
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