Basic Anatomy of the Dancer's Ankle and Foot

Original Editor - Carin Hunter based on the course by Michelle Green-Smerdon
Top Contributors - Carin Hunter, Jess Bell, Kim Jackson, Wanda van Niekerk and Olajumoke Ogunleye

Introduction

Tibia, Fibula and Talus

"The ankle and foot are complex and detailed structures that bear the weight of the whole body, and are designed to showcase a beautiful work of art."

The ankle and foot are part of a very complex system. This part of the body has to cope with high compressive and shearing forces and, at the same time, it has to offer a high degree of stability. The ankle is the kinetic link between the foot and structures that are higher up in the body. Moreover, the foot is the point where the body interacts with the ground and has to control multi-axial motions, which occur simultaneously.

Transverse-tarsal joint

Very simply, the ankle is made up of three bones, the tibia, fibula and talus and three joints:

1. The transverse-tarsal joint which works together with the talocalcaneal joint
2. The talocalcaneal joint which controls inversion and eversion
3. The tibiotalar joint which helps with stability, flexion and extension

Foot Summary

1. Hind foot
   1. Bones
      1. Talus
         1. This is the highest foot bone
         2. There are no tendons attached to it, only the deltoid ligament
         3. Approximately 60 percent of the surface of the talus is covered by articular cartilage
         4. It has a poor blood supply and therefore relatively poor healing
      2. Calcaneous
      3. Lateral and medial malleolus
   2. Joints
      1. Tibiotalar Joint:
         1. The talus is at its widest anteriorly, meaning the joint is more stable in dorsiflexion
         2. The conforming geometry of the tibiotalar joint is believed to contribute to the stability of the joint - in stance phase, the geometry of the joint alone is sufficient to provide resistance to eversion; otherwise stability is derived from the soft tissue structures.
      2. Subtalar joint:
         1. Absorbs rotational stress from structures higher up in the body
      3. Transverse tarsal joint:
         1. Transitional link between the hindfoot and forefoot
2. Mid Foot
   1. Bones
      1. Navicular
         1. The navicular has a poor blood supply
         2. The main attachment for the posterior tibial tendon is on medial side
      2. Cuboid
      3. Three cuneiforms (medial, intermedius, lateral)
         1. These bones are important for stability along with the plantar and dorsal ligaments
   2. Joints
      1. Five tarsal-metatarsal joints, also known as the Lisfranc joint
   3. Connective tissue, ligaments, muscles and tendons
      1. Plantar fascia
         1. The plantar fascia is responsible for forming the arches of the feet and is a shock absorber when dancing
3. Forefoot
   1. Bones
      1. 14 phalanges
      2. Five metatarsals
         1. The metatarsal heads are the main weightbearing surface in the following ballet positions: Releve, quarter pointe, demi-pointe, and three quarter pointe.
      3. Two sesamoid bones:
         1. These are located inside the flexor hallucis brevis tendon and allow the toe to move up and down.
   2. Joints
      1. Metatarsophalangeal joints
   3. Ligaments, muscles and tendons
      1. The first metatarsal bone is the location for the attachment of several tendons and is important for its role in propulsion and weight bearing.

Ligaments of the Foot and Ankle

1. Medial Ligaments
   1. The deltoid ligament is fan shaped, comprising of four ligaments and resists eversion:
      1. Anterior tibiotalar ligament (deep component)
      2. Tibiocalcaneal ligament
      3. Tibionavicular ligament
      4. Posterior tibiotalar ligament (deep component)
   2. Expansion of the joint capsule
      1. Spring ligament: Cradles and supports the talar head
      2. Lisfranc ligaments: Series of ligaments that stabilise the tarsometatarsal joints and provide stability to the arch of the foot. The plantar ligament is stronger than the dorsal ligament.
      3. Inter-metatarsal ligament: This is found between the tarsal bones and keeps the metatarsals moving in sync. If the nerve running between these joints gets irritated, this can result in a Morton's neuroma.
         

         Pointe with Good Alignment
2. Lateral Ligaments
   1. The lateral ankle is commonly injured in ballet dancers
   2. Anterior talofibular ligament
      1. Tightens in plantarflexion
      2. Many authors conclude that this is the weakest ligament
   3. Calcaneo-fibular ligament
      1. Tightens in dorsiflexion
   4. The following ligaments contribute to ankle stability
      1. Posterior talofibular ligament
      2. Anterior-inferior talofibular ligament
      3. Posterior-inferior talofibular ligament

Ballet Specific Ligament Anatomy

• In a demi-plié, when the ankle is in dorsiflexion, the anterior talofibular ligament relaxes and the calcaneo-fibular ligament is under tension
• The opposite is expected en pointe (when the ankle is in plantarflexion), although no studies have been done to examine extreme position en pointe
• Strain in the anterior talofibular ligament increases with increasing plantarflexion, which is further accentuated during compressive loading through the ankle
• Maximum plantarflexion en pointe places the anterior talofibular ligament parallel to the fibula, which causes it to function as a primary stabiliser of the lateral ankle
• This places the anterior talofibular ligament at particular risk (weakest and at its longest at maximal tension force)

Syndesmosis

This ligament is made up of the:

1. Anterior-inferior talofibular ligament
2. Interosseus membrane
3. Posterior-inferior talofibular ligament
4. Transverse ligament
5. Interosseus ligament

The function of this ligament is to hold the tibia and fibula together at the appropriate distance and form a mortise where the talus sits.

Muscles of the Foot and Ankle

1. Extrinsic Foot Muscles

These muscles have contractile portions that lie outside the ankle, in the leg, but their tendons insert onto the bones of the foot in such a way that ankle motion occurs when these muscles contract. There are four four muscle compartments, separated by fascia: the Superficial Posterior Compartment, Deep Posterior Compartment and the Lateral Compartment, which are all plantar flexors, and the Anterior Compartment, which are dorsiflexors.

1. Superficial Posterior Compartment (plantar flexors)
   1. Gastrocnemius
      1. Action: Plantarflexion when knee is extended, flexion of the knee and also raises the heel during walking
      2. Insertion: Posterior surface of the calcaneus via Calcaneal Tendon (Achilles Tendon)
   2. Soleus
      1. Action: Plantarflexion and steadies the leg on the foot
      2. Insertion: Posterior surface of the calcaneus via Calcaneal Tendon (Achilles Tendon)
   3. Plantaris
      1. Action: Weakly assists gastrocnemius in plantarflexion
      2. Insertion: Posterior surface of the calcaneus via Calcaneal Tendon (Achilles Tendon)
2. Deep Posterior Compartment (plantar flexors)
   1. Flexor hallucis longus
      1. Action: Inversion
      2. Insertion: On the plantar surface of the first toe
   2. Flexor digitorum longus
      1. Action: Inversion
      2. Insertion: On the plantar surface second to fifth toes
   3. Tibialis posterior
      1. Action: Inversion
      2. Insertion: Navicular, medial cuneiform, second to fourth toes, other cuneiforms, cuboid
3. Lateral Compartment (plantar flexors)
   1. Peroneus longus
      1. Action: Eversion and plantar flexion
      2. Insertion: First metatarsal, medial cuneiform and first toe
   2. Peroneus brevis
      1. Action: Eversion
      2. Insertion: Proximal end of the fifth metatarsal
4. Anterior Compartment (dorsiflexors)
   1. Tibialis anterior
      1. Action: Inversion
      2. Insertion: First toe and medial cuneiform
   2. Extensor hallucis longus
      1. Action: Inversion
      2. Insertion: Dorsal aspect of base of distal phalanx of big toe
   3. Extensor digitorum longus
      1. Action: Dorsiflexion and extends lateral four digits
      2. Insertion: Middle & distal phalanges of lateral four digits
   4. Peroneals
      1. Action: Dorsiflexion, aids eversion
      2. Insertion: Dorsum of the base of the 5th metatarsal

2. Intrinsic Foot Muscles

These muscles all originate and insert within the foot. They are known to move the toes and stabilise the foot. Dancers refer to these muscles as the “core” muscles of the foot.

The three largest muscles are abductor hallucis, flexor digitorum brevis and quadratus plantae. They all provide support and stability to the arch. In dancers, these muscles require strength and control. A dancer needs to learn to work with “straight” toes, which includes providing counter-stability to the metatarsals when pointing.

Four Muscle Layers of the Plantar Foot

	Muscles	Tendons
Layer One	Abductor hallucis Flexor digitorum brevis (FDB) Abductor digiti minimi		First Layer
Layer Two	Quadratus plantae         Lumbrical muscles	Flexor digitorum longus (FDL)         Flexor hallucis longus (FHL)	Second Layer
Layer Three	Flexor hallucis brevis         Oblique and transverse heads of the adductor hallucis         Flexor digiti minimi brevis		Third Layer
Layer Four	Dorsal interosseous         Plantar interosseus	Peroneus longus Tibialis posterior	Fourth Layer

Plantar fascia

• This is made up of strong fibrous tissue
• It originates deep within the plantar surface of the calcaneus and inserts on the base of each of the toes
• When the toes are in dorsiflexion, the fascia tightens and supports the arch
• Windlass mechanism: The windlass mechanism is a mechanical model that describes the manner through which the plantar fascia supports the foot during weight-bearing activities and provides information regarding the biomechanical stresses placed on plantar fascia
  • For more information, please see Windlass Test

Arches of the foot

Arches

The purpose of the three arches of the foot are:

1. Spring
2. Weight bearing
3. Shock absorption
4. To provides flexibility to the foot to facilitate function

Medial arch of the foot

1. Medial Longitudinal Arch (MLA)

This is the highest arch due to the shape of bones.

1. Bones
   1. The first three metatarsal
   2. Three cuneiforms
   3. Navicular
   4. Talus
   5. Calcaneus
2. Ligaments
   1. Spring ligament
   2. Deltoid ligament
   3. Interosseus ligament
   4. Plantar aponeurosis
   5. Long and short plantar ligaments
3. Muscles
   1. Tibialis posterior
   2. Tibialis anterior
   3. Flexor hallucis longus
   4. Flexor digitorum longus
   5. Short muscles of the big toe

2. Lateral Longitudinal Arch (LLA)

Lateral Arch of the foot

The only arch to lie on the ground in a standing position.

1. Bones
   1. Calcaneus
   2. Cuboid
   3. Four and fifth metatarsals
2. Ligaments
   1. Long and short plantar ligaments
   2. Interosseus ligament
   3. Plantar aponeurosis
3. Muscles
   1. Peroneus longus and brevis
   2. Flexor digitorum longus
   3. Short muscles of the little toe

Demi Pointe with weight bearing surface on the Transverse Arch

3. Transverse Arch

1. Bones
   1. Wedge shape of the lateral and intermediate cuneiform
   2. Metatarsal bases
   3. Cuboid
   4. Three cuneiforms
2. Ligaments
   1. Deep transverse ligament
   2. Dorsal and plantar ligament
3. Muscles
   1. Peroneus longus and brevis
   2. Transverse head of adductor hallucis
   3. Slips of tibial posterior