🦶

Ankle Complex and Foot Anatomy

Jun 23, 2024

Ankle Complex and Foot Anatomy

Ankle Structure

  • Bones Involved:

    • Tibial bone
    • Fibular bone
    • Talus (Tais) bone
  • Joints Formed:

    • Proximal tibiofibular joint
    • Distal tibiofibular joint
    • Talocrural joint

Tibiofibular Joints

  • Proximal Tibiofibular Joint:

    • Limited movement
  • Distal Tibiofibular Joint:

    • Maintains ankle stability
    • Key ligaments:
      • Anterior tibiofibular ligament
      • Posterior tibiofibular ligament
      • Calcaneal fibular ligament

Talocrural Joint

  • Formed by tibia, fibula, and talus bones
  • Primary Movements: Dorsiflexion and plantar flexion
  • Weight-bearing responsibilities mainly between tibia and talus bones

Ligaments

  • Lateral Side Ligaments:

    • Anterior tibiofibular ligament
    • Posterior tibiofibular ligament
    • Calcaneal fibular ligament
  • Medial Side Ligaments:

    • Deltoid ligament (4 parts)
      • Anterior tibiotalar ligament
      • Posterior tibiotalar ligament
      • Tibiocalcaneal ligament
      • Tibionavicular ligament

Joint Mechanics

  • Closed Pack Position: Full dorsiflexion
  • Open Pack Position: 10 degrees plantar flexion
  • End Feel: Firm (due to ligament protection)

Foot Anatomy

  • Bone Groups:
    • Hindfoot: Talus, calcaneus
    • Midfoot: Navicular, cuneiforms, cuboid
    • Forefoot: Metatarsals and phalanges

Joints

  • Subtalar Joint: Talus and calcaneus
    • Movements: Inversion, eversion
    • Functions: Stability on uneven ground, weight shifting

Arches of the Foot

  • Medial Longitudinal Arch:

    • Formed by: Calcaneus, talus, navicular, cuneiforms, first 3 metatarsals
  • Lateral Longitudinal Arch:

    • Formed by: Calcaneus, cuboid, 4th and 5th metatarsals
  • Transverse Arch:

    • Formed by: Cuneiforms, cuboid

Muscles Acting on Ankle and Foot

Compartments

  • Superficial Posterior Compartment:

    • Muscles: Gastrocnemius (medial and lateral heads), Soleus, Plantaris
    • Functions: Ankle plantar flexion, knee flexion (except soleus)
  • Deep Posterior Compartment:

    • Muscles: Tibialis posterior, Flexor digitorum longus, Flexor hallucis longus
    • Mnemonic: Tom, Dick, and Harry (Tibialis posterior, Flexor digitorum longus, Flexor hallucis longus)
  • Anterior Compartment:

    • Muscles: Tibialis anterior, Extensor digitorum longus, Extensor hallucis longus
    • Functions: Dorsiflexion, toe extension
  • Lateral Compartment:

    • Muscles: Fibularis longus, Fibularis brevis, (occasionally Fibularis tertius)
    • Functions: Plantar flexion, eversion
    • Identification: Fibularis longus (inserts at base of 1st metatarsal), Fibularis brevis (inserts at 5th metatarsal)

Movement Mechanics

  • Dorsiflexion: Convex moving on concave, rolling and gliding
  • Plantar Flexion: Convex moving on concave, rolling posteriorly and gliding anteriorly