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The Ankle and Joints

Function of the foot

• Provide a stable platform • Generate propulsion • Absorb shock

Bones

• Ankle + foot = 28 • foot = 26 bones • Leg: , • Foot:

– Tarsals (7): talus, , navicular, cuboid, and cuneiforms (3) – Metatarsals (5) – Phalanges (14)

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Joints

• Tibiofibular: – articulation between tibia and fibula • amphiarthrodial joint • Ankle joint – Talocrural • articulation between talus and tibia; talus and fibula • classified as a ginglymus

Joints

• Subtalar joint – articulation between talus and calcaneus – classified as arthrodial (gliding) joint • Transverse tarsal joint – articulation between talus, navicular, calcaneus and cuboid bones – classified as arthrodial joint

Joints • Tarsometatarsal – tarsal bones and metatarsal – classified as arthrodial (gliding) joints • Metatarsophalangeal – metatarsals and phalanges – classified as condyloid • Interphalangeal joints (proximal and distal) – phalangeal bones – ginglymus

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Arches of the foot

• Medial longitudinal arch – calcaneus, talus, navicular, cuneiforms (3), and medial metatarsals (3). • Lateral longitudinal arch – calcanueus, cuboid, lateral metatarsals (4 & 5) • Transverse arch – across metatarsals

Classifying Arch Type

• Pes Planus: Flat foot • Pes Cavus: High Arch • Normal

Movements

• Ankle joint – dorsiflexion: “raising the toes” – plantarflexion: “point the toes” • Subtalar & Transverse tarsal joints – Calcaneal inversion and eversion • Interphalangeal joints – flexion – extension

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Movements

• Supination • inversion • plantar flexion • adduction • Pronation •eversion • dorsiflexion • abduction

Summary • Bones of the foot: – tarsals, metatarsals, phalanges • Joints of the foot and ankle – talocrural (ankle) – subtalar – transverse tarsal – metatarsalphalangeal – interphalangeal • Movements – dorsiflexion/plantarflexion (ankle joint) – inversion/eversion (subtalar & transverse tarsal) – flexion and extension of toes about the interphalangeal joints

Muscles

• Plantar flexors • Dorsi flexors • Evertors • Invertors

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Plantar Flexors

• Gastrocnemius • Flexor digitorum longus • • Plantaris • Soleus • Tibialis Posterior

Dorsiflexors

• Tibialis anterior • Peroneus tertius • Extensor digitorum longus

Invertors

• Tibialis anterior • Tibialis posterior • Flexor hallucis longus

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Evertors

• Peroneus longus • Peroneus brevis • Peroneus tertius • Extensor digitorum longus

Extensor digitorum longus (p44) • Origin – lateral of tibia – upper 3/4 of anterior aspect of fibula • Insertion – superior aspect of foot, middle and distal phalanges of four lesser toes • Action – Extension of four lesser toes – dorsal flexion – eversion

Extensor hallucis longus (p45) • Origin – fibula, middle aspect of anterior fibula • Insertion – superior aspect of foot, base of distal phalanx of great toe • Action – dorsiflexion – extension of great toe

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Peroneus tertius (p46)

• Origin – fibula, anterior-lateral surface of lower 1/3 of fibula • Insertion – superior aspect of foot, base of fifth metatarsal • Action – Eversion – Dorsal flexion

Tibialis anterior (p47)

• Origin – Lateral condyle of tibia – Upper two-thirds of anterior-lateral aspect of tibia • Insertion – plantar surface of 1st (medial) cuneiform and 1st metatarsal • Action – Dorsal flexion – inversion

Peroneus brevis (p48)

• Origin – fibula, lower two-thirds, lateral aspect • Insertion – 5th metatarsal tuberosity • Action – eversion

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Peroneus longus (p49)

• Origin – lateral surface of tibia – fibula, upper two-thirds of lateral aspect of fibula • Insertion – inferior aspect of foot, 1st cuneiform and 1st • Action – Eversion – Plantar flexion

Flexor digitorum longus (p50)

• Origin – tibia, middle third, posterior aspect • Insertion – plantar surface of foot, distal phalanx of each of the four lesser toes (no big toe) • Action – ‘toe’ flexion – plantar flexion

Flexor hallucis longus (p51)

• Origin – fibula, lower two-thirds, posterior aspect • Insertion – plantar aspect of foot, base of distal phalanx of big toe (‘hallucis’) • Action – ‘big toe flexion’ – inversion

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Gastrocnemius (p52)

• Origin – medial and lateral epicondyle of the • Insertion – posterior surface of calcaneus • Action – plantar flexion – flexion

Soleus (p54)

• Origin – upper 1/3 posterior shaft of fibula – posterior surface of head of fibula – popliteal line – middle 1/3 of medial border of tibia • Insertion – Posterior surface of the calcaneus • Action – Plantar flexion

Note

• Gastrocnemius and Soleus muscles have a common tendon/insertion (calcaneal tendon or Achilles tendon) • Some texts refer to the combination of the gastrocnemius and soleus as the triceps surae (three headed muscle).

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Plantaris (p53)

• Origin – posterior surface of lateral epicondyle of femur • Insertion – posterior surface of calcaneus • Action – plantar flexion

Tibialis Posterior (p55)

• Origin – middle 1/3 of posterior-lateral surface of tibia – middle 1/3 of posterior-medial surface of fibula • Insertion – plantar surface of foot, lower inner surfaces of navicular, cuneiforms, and 2nd & 3rd metatarsals • Action – plantar flexion – inversion

Summary of muscles • Plantar flexors – gast., sol., flx digitorum long., per longus, tib post, plantaris • Dorsi flexors – tib ant, per tertius, ext dig long • Evertors – per longus, brevis, tertius, ext dig longus • Invertors – tib ant & post, flx hallucis long

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