Ankle and foot anatomy contains all bones, joints, ligaments, muscles, nerves and vascular structures of the ankle and foot region.

Ankle Anatomy

Bones Anatomy:

  • Ankle joint if formed by:
    1. Tibial plafond.
    2. Talus bone.
    3. Medial malleolus
    4. Lateral malleolus
  • The ankle mortise:
    • It is formed by:
      • Tibial plafond
      • Medial malleolus
      • Lateral malleolus
    • It articulates with the dome of talar body.
    • The dome of talar body is wider anteriorly, so the mortise widens and ankle becomes more stable in dorsiflexion.
  • Motions at ankle joint:
    1. Plantar flexion (23 to 48 ْ ).
    2. Dorsiflexion (10 to 23 ْ ).
    3. Inversion / Eversion and Rotation.

Ligamentous Anatomy:

1. Lateral ankle ligaments:

  • They function as a restraint to varus / inversion forces at ankle:
    1. Anterior talofibular ligament (ATFL):
      • Originates from anteroinferior aspect of lateral malleolus (1 cm proximal to its tip) and extends to lateral aspect of talar neck.
      • Physical exam: anterior drawer test of the ankle in 20° of plantar flexion.
      • Its Injury causes low ankle sprains.
    2. Calcaneofibular ligament (CFL):
      • Extends from tip of lateral malleolus to lateral aspect of calcaneus.
      • Physical exam: inversion (supination) test and talar tilt test.
      • Its injury is rare (low ankle sprain).
    3. Posterior talofibular ligament (PTFL):
    4. Lateral Talocalcaneal Ligament (LTCL):
      • It’s a short narrow ligamentous band that connects the lateral process of the talus to the lateral surface of the calcaneus.
      • Located anterior and medial to calcaneofibular ligament.
      • Its function is to stabilize the talocalcaneal joint.
  • ATFL is the weakest ankle ligament.
  • PTFL is the strongest ankle ligament.

2. Deltoid ligament complex:

  • Deltoid ligament the main ankle stabilizer during stance:
    1. Deep deltoid ligament:
      • Extends from apex of medial malleolus to medial talar body.
      • Its function primarily to resist lateral talar translation.
    2. Superficial deltoid ligament:
      • Extends from distal medial malleolus to navicular bone, sustentaculum tali of calcaneus, medial talus, and spring ligament.
      • Its Function primarily to resist valgus/eversion ankle forces.\
  • Physical exam: Deltoid Ligament Test.
  • Deltoid ligament injuries occur in ankle fracture, high ankle sprain and syndesmosis injury.

3. Calcaneonavicular Ligament (Spring Ligament):

  • It extends from the sustentaculum tali to the inferior aspect of the navicular.
  • It’s a static stabilizer of the medial longitudinal arch and head of the talus.
  • Calcaneonavicular ligament is the most likely ligament to be attenuated in a patient with a type II flatfoot deformity secondary to posterior tibial tendon dysfunction.

4. Syndesmosis Ligaments:

  • Syndesmosis Ligaments consist of:
    1. Anterior-inferior tibiofibular ligament (AITFL)
    2. Posterior-inferior tibiofibular ligament (PITFL)
    3. Transverse tibiofibular ligament (TTFL)
    4. Interosseous ligament (IOL).
  • Physical Exam:
    1. External rotation test
    2. Squeeze test
  • Syndesmosis ligaments injuries are seen in:
    1. High ankle sprain & syndesmosis injury
    2. Ankle fracture

Foot Anatomy

  • The foot anatomy is divided into:
    1. Hindfoot.
    2. Midfoot.
    3. forefoot.

Hind-foot anatomy:

  • Hindfoot includes talus, calcaneus, and cuboid bones.
  • Subtalar, calcaneocuboid (CC), and talonavicular (TN) joints are also included.
  • Chopart joint: consists of Calcaneo-cuboid and talo-navicular joints, it is also called (transverse tarsal).
  • Hindfoot is responsible primarily of inversion and eversion movement.

Mid-foot anatomy:

  • Midfoot starts at the articulation between navicular and cuneiforms, along with cuboid and fourth and fifth metatarsals.
  • Midfoot also includes tarsometatarsal (TMT) joints.
  • It’s primarily responsible for adduction and abduction movements.
  • Midfoot functions as a transverse roman arch in the axial plane
    • Dorsal surface of the arch is wider than the plantar surface
    • The second metatarsal base acts as a keystone to this arch.
  • Lisfranc joint: (Tarsometatarsal joint) consists of 1st, 2nd and 3rd metatarsocuneiform joints and 4th and 5th metatarsocuboid joints
  • Ligamentous stability to midfoot is provided by longitudinal and transverse ligaments on plantar and dorsal aspects of each joint.
    • Plantar ligaments are thicker and stronger than the dorsal ligaments.
    • The Primary stabilizer of longitudinal arch is the interosseous ligaments while the plantar fascia is a secondary stabilizer.

The Largest and strongest ligaments is the Lisfranc ligament, traveling from medial cuneiform to base of second metatarsal.

  • The Midfoot is also divided into three columns:
    1. Medial column:
      • Includes the first metatarsal, the medial cuneiform, and the navicular.
    2. Middle column:
      • Includes the second and third metatarsals, the middle cuneiform, and the lateral cuneiform.
    3. Lateral column:
      • Includes the fourth and fifth metatarsals and the cuboid.
  • Lateral column has the most sagittal mobility while the middle column has the least.

Fore-foot anatomy:

  • Forefoot includes all structures distal to the Tarso-metatarsal joints (TMT) that include:
    1. Phalanges bones.
    2. Metatarsals bones.
  • Ligaments and tendons of the forefoot include:
    1. Transverse metatarsal ligament.
    1. Conjoined tendon of the adductor hallucis muscles.
    2. Plantar plate.

Motions of the Foot and Ankle

Plane of MotionMotion
Sagittal (X-axis) – Dorsiflexion
– Plantar flexion
Frontal (coronal) (Z-axis)– Inversion
– Eversion
Transverse (Y-axis) Forefoot/midfoot– Adduction
– Abduction
– Ankle/hindfoot
– Internal rotation
– External rotation
Triplanar motion Supination– Adduction
– Inversion
– Plantar flexion
– Pronation
– Abduction
– Eversion
– Dorsiflexion
Motions of the Foot and Ankle

Muscles of the Plantar Foot

Dorsal LayerExtensor digitorum brevis
First Plantar Layer1. Abductor hallucis.
2. Flexor digitorum brevis (FDB).
3. Abductor digiti minimi.
Second Plantar Layer1. Quadratus plantae.
2. Lumbrical muscles.
1. Flexor digitorum longus (FDL).
2. Flexor hallucis longus (FHL).
Medial and lateral plantar arteries
Third Plantar Layer1. Flexor hallucis brevis.
2. Oblique and transverse heads of the adductor hallucis.
3. Flexor digiti minimi brevis.
Fourth Plantar Layer1. Dorsal interosseous..
2. Plantar interosseus
1. Peroneus longus
2.Tibialis posterior
Foot Anatomy – Muscle Layers

Blood Supply to the Foot

  • Blood supply to the foot comes from three primary arteries:
    1. Peroneal (fibular) artery
    2. Posterior tibial artery
    3. Anterior tibial artery
ArteryBranches at ankleBranches in foot
Peroneal (fibular) artery– Posterior lateral malleolar artery.
– Communicating branch.
– Lateral calcaneal branch
Posterior tibial artery– Posterior medial malleolar artery.
– Communicating branch.
– Artery of tarsal canal : dominant blood supply to the talar body
– Lateral plantar arteries
– Medial plantar arteries
Anterior tibial artery– Anterior medial malleolar artery
-Anterior lateral malleolar artery
– Dorsalis pedis artery
Foot Anatomy – Blood supply

Nerves of the Foot

  • Branches of the Tibial nerve:
    1. Medial calcaneal nerve:
      • Innervates plantar medial heel.
    2. Medial plantar nerve:
      • Innervates Abductor Hallucis, FHB, FDB and lumbircals to 2nd and 3rd toes.
    3. Lateral plantar nerve:
      • Innervates adductor hallucis, quadratus plantae, all interossei muscles, lateral two lumbricals and abductor digiti minimus.
      • Provides sensation to plantar lateral foot, lateral fourth toe and fifth toe.

Baxter’s nerve: it’s the first branch of Lateral plantar nerve, courses anterior to the medial tuberosity between the Quadratus plantae and Flexor digitorum brevis.
It gives innervate to the abductor digiti minimus muscle.

  • Sural Nerve:
    • Provides dorsal sensory in 4th web space.
  • Deep peroneal Nerve:
    • Innervates EDB, and EHB in foot.
    • Provides sensation to the first dorsal webspace.
  • Superficial Peroneal Nerve:
    • Medial branch.
    • Lateral cutaneous branch.
  • Saphenous Nerve:
    • Supplies sensation to the medial side of foot.