Ankle and foot

• Bony composition of the 3 parts of the foot

  • Calcaneus (heel bone)
  • Hindfoot (calcaneus and talus)
  • Midfoot (navicular, cuneiform bones, cuboid)
  • Forefoot (metatarsals, phalanges)

  
• Easiest bone to find

  Base of the 5th metatarsal

  
• Navicular bone

  In front of the talus

  
• Functions of the foot and ankle

  • Weight bearing
  • Mobile adaptor
  • Rigid lever during gait
  • Complex with intersegmental coupling/coordination between the joints

  
• Ankle joint (talocrural joint)

  Synovial modified hinge joint located in the lower limb, permitting dorsiflexion/plantarflexion

  
• Ankle joint

  • Formed by the bones of the leg and the foot – the inferior surface of the tibia, its malleolus, the malleolus of the fibular and the inferior transverse tibiofibular ligament form the mortise (bracket shaped socket) for the talus to fit into
  • The body/trochlear surface of the talus is convex from front to back and wider in front than it is behind (wedge shaped)
  • The articular surfaces are covered with hyaline cartilage

  
• Ankle joint line

  Can be gauged from the anterior margins of the lower end of the tibia when the overlying tendons are relaxed

  
• Medial collateral ligament

  • Strong triangular base
  • Attached to the medial malleolus
  • Consists of: Anterior tibio-navicular, Tibio-calcaneal, Posterior tibiotalar

  
• Lateral collateral ligament

  • Originates from the lateral malleolus
  • Comprised of: Anterior talofibular, Posterior talofibular, Calcaneofibular

  
• Dorsiflexion range

  0-20 degrees
• Plantar flexion range

  0-50 degrees
• Dorsiflexion

  The anterior part of the talus is held in the mortise, and the joint is more stable

  
• Plantar flexion

  The space between the malleoli must widen to accommodate the body of the talus
• Limitations to dorsiflexion

  • Bony contact between the anterior surfaces
  • Posterior calf muscle stretched and posterior ligaments

  
• Function of ankle ligaments

  • Vital for guiding movement and maintaining stability of each joint
  • Essential for controlling movement at the extremes of joint range

  
• Anterior talofibular ligament

  Resists plantar flexion and inversion and anterior displacement of the talus on the tibia

  
• Calcaneofibular ligament

  Resists dorsiflexion and inversion

  
• Deltoid ligament

  Resists eversion movements
• Dorsiflexion

  Produced by anterior tibial compartment muscles

  
• Plantar flexion

  Produced by posterior tibial compartment muscles

  
• Subtalar joint/talocalcaneal joint

  Synovial multiaxial joint formed between the facets on the superior surface of calcaneus and the facets on the inferior surface of the talus

  
• Subtalar joint

  • The most important joint in the foot, connects the motion of the foot to that of the leg via the articulation between the calcaneus and the talus

  
• Ligaments of the subtalar joint

  • Lateral talocalcaneal
  • Medial talocalcaneal
  • Interosseous talocalcaneal

  
• Midtarsal joint (chopart's joint)

  Talocalcaneonavicular and calcaneocuboid joints

  
• Talocalcaneonavicular joint

  The head of the talus fits into the concavity formed by the posterior surface of the navicular, the facets of the calcaneus and the plantar Calcano navicular ligament

  
• Plantar calcanonavicular ligament

  Also known as the spring ligament, ties the calcaneus to the navicular and supports the head of the talus

  
• Calcaneocuboid joint

  Saddle shaped joint between the calcaneus and the cuboid bone

  
• Long plantar ligament

  • Origin - plantar surface of the calcaneus
  • Insertion - bases of the 2nd -5th metatarsal bones
  • Function - converts the groove on the plantar surface of the cuboid bone into a tunnel for peroneus longus

  
• Short plantar ligament

  • Short wide band
  • Origin: calcaneus
  • Insertion: plantar surface of the cuboid bone
  • Function - limits flattening of the lateral arch

  
• Inversion/eversion at subtalar and midtarsal joints

  1. 1 ratio
• 1st metatarsal phalangeal joint

  Synovial ellipsoid joint between the head of the 1st metatarsal and the proximal phalanx of the big toe

  
• Ligaments of 1st MTP joint

  • Plantar ligaments - thick band on the plantar surface
  • Collateral ligaments - strong cords attached from the metatarsal head to the proximal phalanx

  
• Movements at 1st MTP joint

  Dorsiflexion, Plantar flexion, Abduction and Adduction
• AROM at 1st MTP joint

  • Flexion = 30-45 degrees
  • Extension = 50-70 degrees
• Metatarsophalangeal joints (2,3,4,5th toes)

  Ovoid joints formed between the metatarsal heads and the base of the proximal phalanges

  
• Ligaments of MTP joints

  • Fibrous capsule attached to the joint margins
  • Plantar ligament on the plantar surface
  • Deep transverse ligaments connecting the plantar ligaments
  • Collateral ligaments - rounded cords on each side of the joint

  
• Medial longitudinal arch


  Formed medially by the calcaneus, talus, navicular, cuneiforms, and first to third metatarsals
• Transverse arch

  Formed by the navicular, cuneiforms, cuboid, and first to fifth metatarsals
• Lateral arch

  Summit is lower than the medial summit, the subtalar articulation is the chief joint, calcaneus cuboid joint is relatively immobile

  
• Foot arches

  • Medial arch (calcaneus, talus, navicular, 3 cuneiform, 1-3 metatarsals)
  • Lateral arch (calcaneus, talus, cuboid, 1st and 5th metatarsal)
  • Transverse arch (cuboid, 3 cuneiform, base of metatarsals)