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

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 is a very complex system. (Brockett and Chapman, 2016). 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 of the foot to higher up in the body. The foot is the body's interaction with the ground and has to control many multi-axial motions occurring simultaneously.

In the ankle and foot there are

• 26 foot bones (28 if include tib and fib)
• 30/33 joints
• 3 true ankle bones
• 29 muscles associated with the foot (19 intrinsic)
• 112 Ligaments

The ankle is made up of

1. Three bones
   1. Tibia
   2. Fibula
   3. Talus
2. Three joints
   1. Transverse-tarsal joint which works together with the talocalcaneal joint
   2. Talocalcaneal joint which controls inversion and eversion
   3. Tibiotalar joint which helps with stability and flexion and extension.

The Foot

1. Hind foot

• Bones
  • Talus – highest foot bone, no tendons attach to it (deltoid lig),mostly cartilage surface, poor blood supply, poor healing
  • Calcaneous – largest foot bone
  • Lateral and medial malleolus
• Joints
  • Talus – highest foot bone, no tendons attach to it (deltoid lig),mostly cartilage surface, poor blood supply, poor healing
  • Calcaneous – largest foot bone
  • Lateral and medial malleolus
  • The talus is at its widest anteriorly, meaning the joint is more stable in dorsiflexion.
  • The conforming geometry of the tibiotalar joint is considered 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
  • Important joint in the foot: subtalar and transverse tarsal joints
  • Subtalar joint – Absorbs rotational stress from higher up
  • Transverse tarsal joint (combo of TN and CC joints) - Transitional link btw hindfoot and forefoot

2. Mid Foot

• Bones
  • Navicular( poor blood supply, main attachment for posterior tibial tendon on medial side)
  • Cuboid
  • Cuneform (3 – medial, intermedius, lateral)(nb for stability with plantar and dorsal lig)
• Joints
  • 5 tarsalmetatarsal joints (Lisfranc joint)
• Ligaments, muscles and tendons
  • Plantar fascia ligament
  • Responsible for forming arches of feet and shock absorber when walking/running

3. Forefoot

• Bones
  • 14 Phalanges
  • 5 Metatarsals (releve, quarter pointe, demi-pointe, three quarter pointe) (metatarsal heads are the main weight bearing surfaces)
  • 2 Sesmoid bones (inside FHB tendon, allows toe to move up and down)
• Joints
  • Phalange metatarsal joints
• Ligaments, muscles and tendons
  • 1st metatarsal bone is the location for the attachment of several tendons
  • Important for role in propulsion and weight bearing

Ligaments of the Foot and Ankle

Medial Ligaments

• Deltoid lig, fan shaped comprising 4 lig, resists eversion:
  • ATTL (deep component)
  • CTL
  • TNL
  • PTTL (deep component)

Expansion of joint capsule

• Spring ligament – cradles and supports the talar head
• Lisfranc ligaments – series of ligaments, stabilizes tarsometatarsal joints, provide stability to the arch of the foot, plantar ligament stronger than dorsal ligament
• Inter-metatarsal ligament – btw tarsal bones, keep metatarsal moving in sync, can irritate nerve resulting in Morton's neuroma

Lateral Ligaments

• Commonly injured side
• ATFL (tightens in PF)(weakest concluded by many authors)
• CFL  (Tightens in DF)

• Contribute to ankle stability
  • PTFL
  • AITFL
  • PITFL
• Russel et al, 2008
• Demi –plié (DF) - ATFL will relax and CFL will be under tension
• Opposite is expected when en pointe (PF) although no studies have been done to examine extreme position en pointe
• Clear- strain in ATFL increases with increasing PF and is further accentuated during compressive loading through the ankle
• Maximum PF en pointe places ATFL parallel to fibula, thus functioning as a primary stabilizer of lateral ankle
• This places ATFL at particular risk – weakest and at its longest at maximal tension force

Syndesmosis

• Ligament formed by
  • AITFL
  • Interosseus membrane
  • PITFL
  • Transverse ligament
  • Interosseus ligament
• Function is to hold the tibia and fibula together at the appropriate distance
• Forms mortise where 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, and the tendons of those muscles insert onto the bones of the foot in such a way that ankle motion occurs when the muscles contract

There are four 4 compartments, separated by fascia

Plantar Flexors

• 1. Superficial Posterior compartment
  • Gastrocnemuis (TA)
  • Soleus (TA)
  • Plantaris
• 2. Deep posterior compartment
  • FHL (inversion) (plantar surface of 1 toe)
  • FDL (inversion) (plantar surface 2-5 toes)
  • Tibialis Posterior (inversion) (navicular, medial cuneiform, 2-4 toes, other cuneiforms, cuboid)
• 3. Lateral compartment
  • PL (eversion, PF first metatarsal) (medial cuneiform and 1 toe)
  • PB (eversion)  (5 toe)

4. Dorsiflexors (Anterior compartment)

• Tibialis anterior (inversion) (1 toe, medial cuneiform
• EHL (inversion)
• EDL
• PT (eversion)

FDL
Origin	Posterior surface of tibia distal to popliteal line
Insertion	Splits into four slips after passing through medial intermuscular septum of plantar surface of foot; these slips then insert on plantar surface of bases of 2nd - 5th distal phalanges
Action	Flexes toes 2 - 5; also helps in plantar flexion of ankle
Innervation	Tibial nerve (S2, S3) (S2, S3)
Arterial Supply	Muscular branch of posterior tibial artery

FHL
Origin	Inferior 2/3 of posterior surface of fibula, lower part of interosseous membrane
Insertion	Plantar surface of base of distal phalanx of great toe
Action	Flexes great toe, helps to supinate ankle, and is a very weak plantar flexor of ankle
Innervation	Tibial nerve (S2, S3) (S2, S3)
Arterial Supply	Muscular branch of peroneal and posterior tibial artery

Tibialis Posterior
Origin	Posterior aspect of interosseous membrane, superior 2/3 of medial posterior surface of fibula, superior aspect of posterior surface of tibia, and from intermuscular septum between muscles of posterior compartment and deep transverse septum
Insertion	Splits into two slips after passing inferior to plantar calcaneonavicular ligament; superficial slip inserts on the tuberosity of the navicular bone and sometimes medial cuneiform; deeper slip divides again into slips inserting on plantar surfaces of metatarsals 2 - 4 and second cuneiform
Action	Principal invertor of foot; also adducts foot, plantar flexes ankle, and helps to supinate the foot
Innervation	Tibial nerve (L4, L5) (L4, L5)
Arterial Supply	Muscular branches of sural, peroneal and posterior tibial arteries

Peroneus Longus
Origin	Head of fibula, upper 1/2 - 2/3 of lateral fibular shaft surface; also anterior and posterior intermuscular septa of leg
Insertion	Plantar posterolateral aspect of medial cuneiform and lateral side of 1st metatarsal base
Action	Everts foot and plantar flexes ankle; also helps to support the transverse arch of the foot
Innervation	Superficial peroneal nerve (L5, S1, S2); may also receive additional innervation from common or deep peroneal nerves (L5, S1, S2)
Arterial Supply	Anterior tibial and peroneal arteries

2. Intrinsic Foot Muscles

These muscles all originate and insert within the foot. They are known to move the toes and stabilize the foot.

“core” muscles of the foot

19 muscles (2 on dorsum – EHB, EDB)

19 muscles (2 on dorsum – EHB, EDB)

3 largest muscles are Abductor Hallucis, FDB, Quadratus Plantae

Provide support and stability of the arch

Most conditions require strength and control of these muscles

Dancer needs to learn to work with “straight” toes – provides counter stability to MT when pointing

Four Muscle Layers of the Plantar Foot

Layer One

Most superficial of all the layers

1. Muscles
   1. Abductor hallucis        
   2. Flexor digitorum brevis (FDB)        
   3. Abductor digiti minimi

Layer Two

1. Muscles
   • quadratus plantae        
   • lumbrical muscles        
2. Tendons
   • flexor digitorum longus (FDL)        
   • flexor hallucis longus (FHL)        
3. Neurovascular structures
   • medial and lateral plantar arteries

Layer Three

1. Muscles
   1. Flexor hallucis brevis        
   2. Oblique and transverse heads of the adductor hallucis        
   3. Flexor digiti minimi brevis

Layer Four

Deepest layer and both tendons travel to their insertion point via fibro-osseus tunnels

1. Muscles
   1. Dorsal interosseous        
   2. Plantar interosseus        
2. Tendons
   1. Peroneus longus
   2. Tibialis posterior        

Plantar fascia

• Strong fibrous tissue
• Originates deep within the plantar surface of the calcaneus and inserts on the base of each of the toes
• Toe DF= tightens fascia, supports arch
• Windlass mechanism

Arches

What makes up the arches of the foot?

Purpose:

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

1. Medial longitudinal arch

Highest arch

1. Bone
   1. Shape of bones
   2. First 3 metatarsals
   3. 3 cuneiforms
   4. Navicular
   5. Talus
   6. calcaneus
2. Ligament
   1. Spring ligament
   2. Deltoid ligament
   3. Interosseus ligament
   4. Plantar aponeurosis
   5. Long and short plantar ligaments
3. Muscle
   1. Tib posterior
   2. Tib anterior
   3. FHL
   4. FDL
   5. Short muscles of the big toe

2. Lateral longitudinal arch

Lies on ground in standing position

1. Bone
   1. Shape of the bones
   2. Calcaneus
   3. Cuboid
   4. 4th and 5th metatarsals
2. Ligament
   1. long and short plantar ligaments
   2. Interosseus ligament
   3. Plantar aponeurosis
3. Muscle
   1. Peroneus longus and brevis
   2. Flexor digitorum longus
   3. Short muscles of the little toe

3. Transverse Arch

1. Bone
   1. Wedge shape of the lateral and intermediate cuniform
   2. Metatarsal bases
   3. Cuboid
   4. 3 cuneiform
2. Ligament
   1. Deep transverse ligament
   2. Dorsal and plantar ligament
3. Muscle
   1. Peroneus longus and brevis
   2. Transverse head of adductor hallucis
   3. Slips of tibial posterior