The Ankle and Foot



The ankle and foot are comprised of three important joints:

  • tibiofibular
  • talocrural, and
  • subtalar.

Also:

  • 28 bones including distal tibia and fibula (not including sesmoid bones)
  • 35 articulations
  • 29 muscles control the bones and articulations (18 in foot and 11 in the leg)
  • 3 arches: medial longitudinal, lateral longitudinal, and transverse or anterior.

Pes planus: flat feet (individuals who pronate are often flat footed).

Pes cavus: high arched (individuals who supinates often have pes cavus).

Range of Motion

End feel - both extremes of PF and DF have a firm capsular end feel.

Close packed position of ankle joint - full dorsiflexion and slight medial rotation of the tibia.

Closed packed position of subtalar joint - eversion.

Capsular Pattern - F, E

  • Plantar flexion: 0- 50°
  • Dorsiflexion: 0-20°
  • Inversion: 5°
  • Eversion: 5°
  • Pronation: 15-30°
  • Supination: 45-60°
  • ABD: 10°
  • ADD: 20°

Muscles

Muscles that dorsiflex the foot: tibial anterior (with inversion), extensor hallicus longus (with inversion), extensor digitorum longus (with eversion), and peroneus tertius (with eversion). Muscles that plantar flex the foot: tibialis posterior, flexor hallicus longus and flexor digitorum longus (all with inversion.) Pure plantar flexion is achieved with the triceps surae muscle (gastrocnemius and soleus.) Peroneus longus and brevis plantar flex the foot with eversion.

Ligaments

Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint. Four ligaments connect the femur and tibia: The deltoid ligament (also called medial collateral ligament for the talocrural joint) provides stability to the inner (medial) aspect of the ankle. It is considered one of the strongest ligaments in the body. It resists rotation, eversion, terminal dorsiflexion, terminal plantar flexion, and AP glide of the talar joint.

The lateral collateral ligament (LCL) provides stability to the outer (lateral) aspect of the ankle. It is made up of the anterior talofibular ligament (associated with first degree sprains), calcaneofibular ligament, and posterior talofibular ligament. Together, they resist rotation, inversion, terminal dorsiflexion, terminal plantar flexion, and AP glide. The distal tibiofibular joint gains stability from the anterior and posterior tibiofibular ligaments. Together they prevent the leg bones from spreading. The subtalar joint is strengthened via four ligaments; the lateral talocalcaneal ligament (often sprained along with the anterior talofibular ligament when inversion occurs), medial talocalcaneal ligament, interosseus talocalcaneal ligament, and cervical ligament.

Tendons

Tendons are tough cords of tissue that connect muscle to bone. In the distal leg, the most important tendon is the Achilles tendon. Orthopedic Tests Anterior drawer- tests for ligament laxity of talocrural joint Talar tilt- tests for ligament laxity of subtalar joint Eversion Kleiger test Homan’s (DF)- testing for DVT Thompson- squeeze calf- tests for DVT Neuroma squeeze Fascial rub