Exam 3 ankle

The ankle complex

• ankle joint

• subtalar joint

The ankle joint

• Tibiotalar joint

• Fibulotalar joint

• Tibiofibular joint

Tibiotalar joint

• Talus articulates with the tibia

• MAIN SOURCE OF MOTION

Tibiofibular joint

• Tibia and fibula joined together by dense fibrous tissue called syndesmosis

Ankle holds

5 times body weight

knee joint holds

3 times body weight

hip joint holds

2 times body weight

Main joints of the ankle complex

distal fibular joint

Main joints of the ankle complex

talocrural joint

Main joints of the ankle complex

subtalar joint

Labelling of the ankle and foot

Ankle complex

• ankle joint and subtalar joint

• 6 degrees of freedom

• multi-axial/tri-axial

Ankle joint

• ankle mortise/ Talocrural joint

• Darthrotic joint: freely moveable

• Hinge joint

• Dorsiflexion (internal rotation) and plantar flexion (external rotation) in the sagittal plane

Subtalar joint

• Eversion and inversion on the coronal plane

• Pronation and supination on oblique plane

Movements of the subtalar joint during the gait

• Inversion: calcaneus turns inwards

• Ankle joint is stabilized in subtalar inversion

• ligaments/ muscles/ tendons outside of the ankle become taut

• Inversion of the calcaneus also occurs during the initial contact phase and terminal phase

• Eversion: calcaneus turns outward

• Eversion occurs during loading response and midstance – foot and ankle changes from a lever to a shock absorber

Major functions of the foot and ankle

• Supporting body weight

• Shock absorption

• Balance

• Transferring ground reaction forces directly

• Compensating for proximal joint and muscle misalignments

• Sub for hand function with loss of upper extremities

Flexor tendons

bottom of toes

Extensor tendons

top of toes

Inversion

• 30 degrees

• Movement on the frontal plane

• The plantar surface of the foot faces toward the midline of the body

• Position: inverted and varus

Eversion

• 20 degrees

• Movement on the frontal plane

• The plantar surface of the foot faces away from the midline of the body

• Position: everted and valgus

ROM of the ankle and foot

• Plantar flexion

• Dorsiflexion

• Eversion

• Inversion

• Abduction

• Adduction

Open chain pronation

• eversion

• abduction

• dorsiflexion

• leg and talus held stable

Open chain supination

• inversion

• adduction

• plantarflexion

• leg and talus held stable

Subtalar joint closed chain pronation

• adduction and plantarflexion of the talus associated with INTERNAL 

  rotation of the leg

• Eversion of the calcaneus

• Flexion of the knee

• Anterior tilt of the pelvis

Subtalar joint closed chain supination

• Abduction and dorsiflexion of the talus associated with EXTERNAL rotation of the leg

• Inversion of the calcaneus

• extension of the knee

• posterior tilt of the pelvis
  

Pronated Foot and ankle characteristics

• Pelvic rotation

• Internal femur rotation

• Valgus knee

• Internal tibial rotation

• Pronated foot position