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