Ankle Joint

The ankle joint complex is a crucial structure that connects the leg to the foot, enabling locomotion and providing stability during weight-bearing activities. It consists of two primary articulations: the talocrural joint (true ankle joint), which is a hinge joint allowing dorsiflexion and plantarflexion, and the subtalar joint, which permits inversion and eversion movements essential for adapting to uneven terrain.

Quick Reference

Attribute	Details
Joint Type	Talocrural: Hinge (synovial); Subtalar: Gliding (synovial)
Bones	Tibia, fibula, talus, calcaneus
Articulations	Talocrural (tibia/fibula with talus), subtalar (talus with calcaneus)
Degrees of Freedom	2 (dorsiflexion/plantarflexion, inversion/eversion)
Key Ligaments	ATFL, CFL, PTFL (lateral complex), deltoid ligament (medial)
Key Structures	Medial malleolus, lateral malleolus, Achilles tendon, tibialis posterior tendon
Primary Actions	Dorsiflexion, plantarflexion, inversion, eversion
Innervation	Deep fibular, tibial, superficial fibular nerves

Anatomy

The ankle joint complex is composed of two distinct but functionally related joints that work together to provide the foot with mobility and stability during weight-bearing activities.

Talocrural Joint (True Ankle Joint)

The talocrural joint is the primary ankle articulation, formed by the distal tibia and fibula creating a mortise that receives the dome of the talus. The medial malleolus of the tibia and lateral malleolus of the fibula grip the talus on either side, creating a highly stable hinge joint. This configuration allows for dorsiflexion (bringing the foot toward the shin) and plantarflexion (pointing the foot downward) while restricting other motions.

The articular surface of the talus is wedge-shaped, being wider anteriorly than posteriorly. This anatomical feature means the ankle is most stable in dorsiflexion when the wider anterior portion of the talus is wedged into the mortise, and slightly less stable in plantarflexion when the narrower posterior portion is engaged.

Subtalar Joint

The subtalar joint is formed by the articulation between the inferior surface of the talus and the superior surface of the calcaneus. This joint primarily allows inversion (tilting the sole of the foot inward) and eversion (tilting the sole of the foot outward), which are essential for adapting to uneven ground and maintaining balance during ambulation.

Ligament Complexes

Lateral Ligament Complex: The lateral ankle is stabilized by three separate ligaments that form the lateral collateral ligament complex. The anterior talofibular ligament (ATFL) is the weakest and most frequently injured, running from the lateral malleolus to the talus. It resists anterior displacement and inversion when the ankle is plantarflexed. The calcaneofibular ligament (CFL) runs from the lateral malleolus to the calcaneus and resists inversion throughout the range of motion. The posterior talofibular ligament (PTFL) is the strongest lateral ligament, resisting posterior displacement of the talus.

Medial Ligament Complex (Deltoid Ligament): The medial ankle is stabilized by the deltoid ligament, a strong, fan-shaped structure that is actually composed of four separate components. It runs from the medial malleolus to the navicular, talus, and calcaneus, providing resistance against eversion forces and preventing excessive lateral displacement of the talus. The deltoid ligament is significantly stronger than the lateral ligaments, making medial ankle sprains much less common.

Range of Motion

Normal ankle range of motion varies with measurement technique, age, and individual factors. The ankle's motion occurs primarily in the sagittal plane (dorsiflexion/plantarflexion) and frontal plane (inversion/eversion).

Motion	Normal Range	Notes
Dorsiflexion	0-20°	Essential for squatting, stairs, and gait; often limited in athletes
Plantarflexion	0-50°	Required for running, jumping, and toe-off during gait
Inversion	0-35°	Occurs primarily at subtalar joint; combined with plantarflexion
Eversion	0-15°	Occurs primarily at subtalar joint; combined with dorsiflexion

info

Adequate ankle dorsiflexion (at least 10-15° with knee extended, 35-40° with knee flexed) is critical for proper squat mechanics and injury prevention. Limited dorsiflexion often leads to compensatory movement patterns at the knee and hip.

Joint Actions

The ankle's actions include sagittal plane motion at the talocrural joint and frontal plane motion at the subtalar joint, with these movements often occurring in combination during functional activities.

Dorsiflexion

Dorsiflexion brings the dorsum (top) of the foot toward the anterior shin, decreasing the angle between the foot and leg.

Prime Movers:

• Tibialis anterior
• Extensor hallucis longus
• Extensor digitorum longus

Function: Essential for clearing the foot during swing phase of gait, controlling descent during squats and stairs, and decelerating the tibia during landing activities. Limited dorsiflexion is associated with increased injury risk and altered movement patterns.

Plantarflexion

Plantarflexion points the foot downward, increasing the angle between the foot and leg.

Prime Movers:

• Gastrocnemius
• Soleus
• Plantaris
• Tibialis posterior
• Fibularis longus and brevis

Function: Critical for propulsion during walking and running (toe-off phase), jumping, rising onto toes, and maintaining balance. The ankle plantarflexors are among the strongest muscles in the body relative to their size.

Inversion

Inversion tilts the sole of the foot medially (inward), occurring primarily at the subtalar joint.

Prime Movers:

• Tibialis anterior
• Tibialis posterior
• Flexor digitorum longus
• Flexor hallucis longus

Function: Allows adaptation to uneven surfaces, contributes to the windlass mechanism of the foot during gait, and helps maintain arch integrity. Excessive inversion is the mechanism for most ankle sprains.

Eversion

Eversion tilts the sole of the foot laterally (outward), occurring primarily at the subtalar joint.

Prime Movers:

• Fibularis longus
• Fibularis brevis
• Fibularis tertius
• Extensor digitorum longus

Function: Adapts to uneven surfaces (especially when walking on lateral slopes), helps absorb shock during landing, and assists with balance. Weakness in eversion can contribute to recurrent ankle instability.

Muscles Acting On It

The ankle joint is controlled by muscles originating from the leg, with tendons crossing the ankle to insert on the foot. These muscles are organized into four compartments: anterior, lateral, superficial posterior, and deep posterior.

Muscle	Primary Action	Role	Notes
Gastrocnemius	Plantarflexion	Prime mover	Two-joint muscle (also flexes knee); provides power for jumping
Soleus	Plantarflexion	Prime mover	Single-joint muscle; crucial for standing and walking
Plantaris	Plantarflexion	Synergist	Small muscle with long tendon; may be absent in some individuals
Tibialis Anterior	Dorsiflexion, inversion	Prime mover	Most powerful dorsiflexor; critical for foot clearance in gait
Tibialis Posterior	Plantarflexion, inversion	Prime mover	Primary dynamic stabilizer of medial arch; key for gait
Fibularis Longus	Plantarflexion, eversion	Prime mover	Supports lateral and transverse arches
Fibularis Brevis	Eversion	Prime mover	Provides lateral ankle stability
Fibularis Tertius	Dorsiflexion, eversion	Synergist	May be absent in ~10% of population
Flexor Hallucis Longus	Plantarflexion, inversion	Synergist	Flexes great toe; important for push-off
Flexor Digitorum Longus	Plantarflexion, inversion	Synergist	Flexes lateral four toes
Extensor Hallucis Longus	Dorsiflexion, inversion	Synergist	Extends great toe
Extensor Digitorum Longus	Dorsiflexion, eversion	Synergist	Extends lateral four toes

tip

The triceps surae (gastrocnemius and soleus combined) is one of the most powerful muscle groups in the body, generating forces 2-3 times body weight during running and jumping activities.

Mobility Work

Ankle Circles

Active Ankle Circles

1. Sit or stand with foot off ground
2. Trace large circles with your foot
3. Perform 10 circles clockwise, 10 counterclockwise
4. Move slowly through full available range
5. Repeat 2-3 times per side

Alphabet Drill

1. Sit with foot elevated off ground
2. Use your big toe to "write" the alphabet in the air
3. Move through full ankle ROM with each letter
4. Perform once per side daily

Banded Mobilizations

Banded Ankle Distraction

1. Anchor resistance band to stable object
2. Loop band around ankle at level of talocrural joint
3. Step away to create tension pulling ankle backward
4. Perform small lunges or ankle pumps
5. Hold 2-3 minutes per side

Banded Dorsiflexion Mobilization

1. Place band around ankle mortise
2. Anchor band behind you at ground level
3. Step forward into lunge position
4. Drive knee forward over toes while keeping heel down
5. Hold stretches for 5 seconds, repeat 10-15 times
6. Perform 2-3 sets per side

Calf Stretches

Gastrocnemius Stretch (Straight Knee)

1. Place hands on wall at shoulder height
2. Step one foot back, keeping knee straight
3. Keep heel down and toes pointing forward
4. Lean forward until stretch felt in upper calf
5. Hold 30-60 seconds each side
6. Repeat 2-3 times

Soleus Stretch (Bent Knee)

1. Same position as gastrocnemius stretch
2. Bend back knee while keeping heel down
3. Lean forward until stretch felt in lower calf/Achilles
4. Hold 30-60 seconds each side
5. Repeat 2-3 times

Wall Ankle Dorsiflexion Stretch

1. Face wall in standing position
2. Place toe of one foot against wall
3. Drive knee forward toward wall
4. Measure distance from wall to toes (goal: 4-5 inches)
5. Hold 30 seconds, repeat 5 times per side

Foot/Ankle Strengthening

Heel Raises

1. Stand with feet hip-width apart
2. Rise up onto toes as high as possible
3. Lower slowly with control
4. Perform 3 sets of 15-20 repetitions
5. Progress to single-leg or weighted variations

Toe Raises

1. Stand with feet hip-width apart
2. Lift toes/forefoot off ground while keeping heels down
3. Hold 2-3 seconds at top
4. Perform 3 sets of 15-20 repetitions

Common Issues

Lateral Ankle Sprains

Lateral ankle sprains are among the most common musculoskeletal injuries, particularly in sports involving jumping, cutting, and running on uneven surfaces.

Mechanism: Inversion injury with or without plantarflexion, typically injuring the ATFL first, then CFL with more severe sprains. Often occurs when landing on another player's foot or stepping on uneven surface.

Grading:

• Grade I: ATFL stretch, minimal swelling, able to bear weight
• Grade II: ATFL partial or complete tear, moderate swelling and pain, difficulty bearing weight
• Grade III: Complete tears of ATFL and CFL (±PTFL), severe swelling and bruising, unable to bear weight

Symptoms: Lateral ankle pain and swelling, tenderness over injured ligaments, instability sensation, difficulty walking.

Management: RICE protocol initially (rest, ice, compression, elevation), early controlled movement preferred over prolonged immobilization, progressive strengthening and proprioceptive training, return to activity when full ROM, strength, and proprioception restored. Chronic instability may require surgical reconstruction.

Medial Ankle Sprains

Medial ankle sprains involving the deltoid ligament are much less common than lateral sprains due to the ligament's strength and the protection from the opposite ankle during eversion.

Mechanism: Eversion force, often with external rotation of the tibia. May be associated with fractures (maisonneuve fracture).

Symptoms: Medial ankle pain and swelling, difficulty bearing weight, may have associated syndesmotic injury or fracture.

Management: Rule out fracture with imaging if indicated by Ottawa Ankle Rules. Conservative treatment similar to lateral sprains but often requires longer recovery. High index of suspicion for associated injuries.

Achilles Tendinopathy

Overuse condition affecting the Achilles tendon, classified as either insertional (at calcaneal attachment) or non-insertional (mid-portion, 2-6 cm above insertion).

Common Causes: Training errors (sudden volume/intensity increase), tight/weak calf muscles, poor footwear, altered biomechanics, decreased ankle dorsiflexion.

Symptoms: Gradual onset of pain and stiffness in Achilles region, worse with activity initially then may warm up, morning stiffness, possible tendon thickening or nodules.

Management: Relative rest with activity modification, progressive eccentric loading program (Alfredson protocol), address contributing factors (calf flexibility, footwear, training loads), avoid corticosteroid injections. Chronic cases may benefit from shockwave therapy or PRP injections.

Limited Ankle Dorsiflexion

Restricted dorsiflexion range of motion is a common finding that can lead to compensatory movement patterns and increased injury risk at the knee and hip.

Common Causes: Tight gastrocnemius/soleus complex, anterior ankle joint capsule restrictions, previous ankle sprains with scar tissue formation, bony impingement, prolonged immobilization.

Consequences: Knee valgus during squatting, forward trunk lean during squats, early heel rise in squats, increased forefoot loading during gait, higher risk of anterior knee pain and ACL injury.

Management: Distinguish between muscle tightness (improves with knee flexion) and joint restriction (no change with knee flexion). Treat with appropriate stretching (gastrocnemius vs soleus), joint mobilizations, soft tissue work, and strengthening in lengthened positions.

Posterior Ankle Impingement

Pinching of structures in the posterior ankle, often involving the posterior talus, os trigonum (accessory bone), or soft tissues.

Common Causes: Repetitive or forced plantarflexion, common in ballet dancers, soccer players (kicking), and gymnasts. May be associated with os trigonum or prominent posterior talar process.

Symptoms: Posterior ankle pain with plantarflexion (especially loaded), tenderness posterolateral to Achilles tendon, pain with relevé (rising onto toes) or kicking motions.

Management: Activity modification avoiding extreme plantarflexion, physical therapy focusing on mobility and strength, anti-inflammatory measures. Persistent cases may require surgical excision of os trigonum or prominent bone.

Ankle Instability (Chronic)

Persistent feeling of ankle giving way or instability following initial ankle sprain, affecting 20-40% of individuals with ankle sprains.

Contributing Factors: Incomplete rehabilitation after initial sprain, ligamentous laxity, proprioceptive deficits, peroneal muscle weakness, altered movement patterns.

Symptoms: Repeated ankle sprains, feeling of instability especially on uneven surfaces, tendency to "roll" the ankle frequently, apprehension with activities.

Management: Comprehensive rehabilitation program focusing on proprioception, balance training (single-leg balance, balance board exercises), peroneal strengthening, functional activities. Ankle bracing or taping for high-risk activities. Surgical stabilization considered for persistent instability after failed conservative treatment.

Related Joints

Knee Joint

The knee and ankle function as a kinetic chain during lower extremity movements. Ankle dorsiflexion restrictions force compensatory movements at the knee, often resulting in knee valgus during squatting and landing activities. The gastrocnemius crosses both joints, creating interdependence between ankle and knee function.

Clinical Relevance: Adequate ankle dorsiflexion (minimum 10° with knee extended) is essential for proper squat mechanics and injury prevention. Limited ankle mobility is associated with increased risk of patellofemoral pain and ACL injury.

Foot Complex

The ankle and foot work intimately together to provide a stable yet mobile base of support. The subtalar joint's inversion and eversion motions work in conjunction with midfoot mobility to adapt to terrain. Ankle position influences arch mechanics and vice versa.

Clinical Relevance: Excessive foot pronation can contribute to tibial internal rotation and altered ankle mechanics. Ankle instability often leads to compensatory foot mechanics. Treatment of ankle conditions should address the entire foot-ankle complex.

Hip Joint

Although not directly adjacent, the hip influences ankle mechanics through the kinetic chain. Hip weakness (particularly glute medius) can lead to dynamic knee valgus, which places altered demands on the ankle. Proximal stability enables distal mobility.

Clinical Relevance: Chronic ankle instability is associated with altered hip muscle activation patterns. Comprehensive lower extremity rehabilitation should address the entire kinetic chain from hip to foot.

Sources

1. Neumann DA. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.

2. Magee DJ, Manske RC. Orthopedic Physical Assessment. 7th ed. Elsevier; 2021.

3. Reese NB, Bandy WD. Joint Range of Motion and Muscle Length Testing. 3rd ed. Elsevier; 2017.

4. Hertel J. Functional anatomy, pathomechanics, and pathophysiology of lateral ankle instability. J Athl Train. 2002;37(4):364-375.

5. Doherty C, Delahunt E, Caulfield B, et al. The incidence and prevalence of ankle sprain injury: a systematic review and meta-analysis of prospective epidemiological studies. Sports Med. 2014;44(1):123-140.

6. Alfredson H, Cook J. A treatment algorithm for managing Achilles tendinopathy: new treatment options. Br J Sports Med. 2007;41(4):211-216.

7. Mason-Mackay AR, Whatman C, Reid D. The effect of reduced ankle dorsiflexion on lower extremity mechanics during landing: A systematic review. J Sci Med Sport. 2017;20(5):451-458.

8. Hoch MC, McKeon PO. Peroneal reaction time after ankle sprain: a systematic review and meta-analysis. Med Sci Sports Exerc. 2014;46(3):546-556.

9. DiGiovanni CW, Kuo R, Tejwani N, et al. Isolated gastrocnemius tightness. J Bone Joint Surg Am. 2002;84(6):962-970.

10. Gribble PA, Bleakley CM, Caulfield BM, et al. Evidence review for the 2016 International Ankle Consortium consensus statement on the prevalence, impact and long-term consequences of lateral ankle sprains. Br J Sports Med. 2016;50(24):1496-1505.