The Ankle and Foot Joints

Function of the foot

• Provide a stable platform• Generate propulsion• Absorb shock

Bones

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

– Tarsals (7): talus, calcaneus, navicular, cuboid, and cuneiforms (3)

– Metatarsals (5)– Phalanges (14)

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

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

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

Plantar Flexors

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

Dorsiflexors

• Tibialis anterior• Peroneus tertius• Extensor digitorum longus

Invertors

• Tibialis anterior• Tibialis posterior• Flexor hallucis longus

Evertors

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

Extensor digitorum longus (p44)• Origin

– lateral condyle 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

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

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 metatarsal

bones• 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

Gastrocnemius (p52)

• Origin– medial and lateral epicondyle of the femur

• Insertion– posterior surface of calcaneus

• Action– plantar flexion– knee 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).

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