Articular Surfaces
- Talar dome (convex): The superior surface of the talus — wider anteriorly than posteriorly. This wedge shape means the joint is more stable in dorsiflexion (wider part fills the mortise) and less stable in plantarflexion (narrower part allows more play). The talar dome is covered with hyaline cartilage on its superior and medial/lateral surfaces.
- Tibial plafond (concave): The inferior articular surface of the distal tibia. Forms the "ceiling" of the mortise.
- Medial malleolus (concave): The medial wall of the mortise, formed by the distal tibia.
- Lateral malleolus (concave): The lateral wall of the mortise, formed by the distal fibula. The lateral malleolus extends further distally than the medial — this is why the ankle is more stable laterally and why inversion sprains (laterally directed force) are far more common than eversion sprains.
Movements and ROM
Functional dorsiflexion requirement: A minimum of 10° of dorsiflexion is needed for normal gait (during the stance phase, the tibia must advance over the planted foot). Less than 10° produces compensatory overpronation at the subtalar joint, early heel rise, and altered gait mechanics.
Capsular Pattern
Plantarflexion > Dorsiflexion
When the talocrural capsule is restricted, plantarflexion is more limited than dorsiflexion. This is counterintuitive (dorsiflexion restriction is more clinically common), but the capsular pattern refers specifically to capsular fibrosis — the anterior capsule (restricting plantarflexion) has more capsular surface area than the posterior capsule.
Resting Position
- 10° plantarflexion, midway between inversion and eversion
- Maximum capsular volume
Close-Packed Position
- Maximum dorsiflexion
- Wide anterior talus fills the mortise; all ligaments taut; maximum bony stability
End-Feels
| Movement |
Normal End-Feel |
Type |
| Dorsiflexion |
Capsular (firm) |
Posterior capsule, Achilles tendon, gastrocnemius-soleus complex, posterior talofibular ligament |
| Plantarflexion |
Capsular (firm) |
Anterior capsule, anterior talofibular ligament, dorsiflexor tendons. May be bony in extreme plantarflexion (posterior talar process contacts the tibia — os trigonum syndrome). |
Ligaments
Lateral Ligament Complex
Anterior Talofibular Ligament (ATFL)
- Attachments: Anterior lateral malleolus → talar neck (anterolateral)
- Function: Resists inversion and anterior talar displacement when the ankle is plantarflexed. The weakest of the three lateral ligaments — it is the first to be injured in an inversion sprain and the most commonly torn ligament in the body.
- Injury mechanism: Inversion with plantarflexion — the classic ankle sprain mechanism (stepping off a curb, landing on another player's foot). The plantarflexed position moves the narrow posterior talus into the mortise, loosening bony stability, and the ATFL is the only restraint against inversion in this position.
- Assessment test: Anterior drawer test of the ankle (stabilize the tibia, pull the foot anteriorly — positive: increased anterior talar shift with a soft end-feel)
- Condition link: conditions/lateral-ankle-sprain
Calcaneofibular Ligament (CFL)
- Attachments: Lateral malleolus (tip) → lateral calcaneus
- Function: Resists inversion in the neutral and dorsiflexed positions. Crosses both the talocrural and subtalar joints — its integrity is important for both.
- Injury mechanism: Higher-grade inversion sprain — after the ATFL tears, continued inversion force tears the CFL. This is a Grade II sprain.
- Assessment test: Talar tilt test (inversion stress with the ankle in neutral — excessive tilt indicates CFL disruption)
Posterior Talofibular Ligament (PTFL)
- Attachments: Posterior lateral malleolus → posterior talus
- Function: Resists posterior talar displacement. The strongest of the three lateral ligaments — rarely torn (only in severe Grade III sprains or dislocations).
Medial Ligament Complex (Deltoid Ligament)
- Attachments: Medial malleolus → talus, calcaneus, navicular, and spring ligament (four bands: anterior tibiotalar, tibionavicular, tibiocalcaneal, posterior tibiotalar)
- Function: Resists eversion, lateral talar shift, and lateral rotation of the talus. The deltoid is much stronger than the lateral complex — this is why eversion sprains are uncommon (the medial malleolus fractures before the deltoid tears in most cases).
- Assessment test: Eversion stress test (positive: medial joint opening). A positive test is serious — it suggests either deltoid rupture or medial malleolar avulsion fracture.
- Condition link: Eversion ankle sprain (much less common; often involves medial malleolar fracture)
Mobilization Techniques
Hands-on instruction is required. The descriptions below provide clinical reference detail for understanding and supervised practice. They are not a substitute for instructor-led technique training. Correct hand placement, force dosage, and tissue response interpretation require hands-on coaching and feedback.
Convex-Concave Rule at the Talocrural Joint
The talar dome is
convex moving within the
concave mortise. When mobilizing the convex talus on the fixed tibia, the glide is in the
opposite direction to the restricted movement.
| Restricted Movement |
Glide Direction |
Reasoning |
| Dorsiflexion |
Posterior talar glide |
Dorsiflexion moves the talus anteriorly into the mortise → convex on concave → glide opposite → posterior |
| Plantarflexion |
Anterior talar glide |
Plantarflexion moves the talus posteriorly → convex on concave → glide opposite → anterior |
General Contraindications
- Absolute: Ankle fracture (malleolar, talar), ankle dislocation, acute syndesmotic disruption, acute Grade III ligament sprain with instability, active infection
- Relative: Acute lateral ankle sprain (Grade I–II — gentle Grade I–II mobilization may begin early for pain modulation), significant effusion, talar dome lesion (osteochondral defect)
Posterior Talar Glide
Purpose: Restores dorsiflexion — the most clinically important talocrural mobilization. Dorsiflexion limitation is the most common ankle restriction and a perpetuating factor for recurrent ankle sprains, Achilles tendinopathy, and altered gait mechanics.
Patient position:
- Supine or long-sitting with the foot over the edge of the table
- Ankle in the resting position (10° plantarflexion) or positioned at the current dorsiflexion end-range
- A mobilization belt can be used for sustained techniques
Hand placement:
- Stabilizing hand: Grips the distal tibia and fibula (the mortise) from the posterior side, holding them firmly against the table
- Mobilizing hand: Web space or thenar eminence contacts the anterior talar neck (just distal to the anterior joint line, on the dorsal foot). Force directed posteriorly (toward the table/floor).
Technique execution:
- Apply a slow, sustained or oscillatory force directed posteriorly on the talus
- Grade I–II: Gentle oscillations for pain modulation — appropriate in the early post-sprain phase (can begin as early as 48–72 hours post-injury for pain relief and to prevent stiffness)
- Grade III–IV: Oscillations at end-range dorsiflexion, into the posterior capsular resistance. The posterior capsule and Achilles complex provide the barrier.
- Rhythm: 1–2 oscillations per second
- Duration: 30–60 seconds per set, 3–5 sets
- Reassess dorsiflexion between sets (weight-bearing lunge test is an excellent functional reassessment)
Indications:
- Decreased dorsiflexion with capsular (firm) end-feel
- Post-ankle sprain stiffness (the most common indication)
- Post-immobilization (cast, boot) dorsiflexion limitation
- Functional dorsiflexion <10° (minimum for normal gait)
Technique notes:
- Common error: Mobilizing the midfoot instead of the talus — ensure the contact is on the talar neck, proximal to the navicular
- Common error: Not stabilizing the tibia — the entire lower leg translates instead of the talus gliding
- Weight-bearing lunge test for reassessment: Patient stands facing the wall, lunges the knee toward the wall with the foot flat. Measure the distance from the great toe to the wall when the heel starts to lift. Normal: ≥10 cm. Compare bilaterally.
- Integration: Address gastrocnemius and soleus tightness first (these are the most common soft tissue restrictions limiting dorsiflexion). If dorsiflexion does not improve after calf stretching, the restriction is capsular — mobilize.
Anterior Talar Glide
Purpose: Restores plantarflexion. Less commonly needed than posterior talar glide but important after anterior ankle capsular injury or post-immobilization in dorsiflexion.
Patient position:
- Prone with the foot over the edge of the table
- Ankle in slight plantarflexion
Hand placement:
- Stabilizing hand: Holds the distal tibia/fibula against the table
- Mobilizing hand: Thenar eminence contacts the posterior talus/calcaneus region. Force directed anteriorly (toward the floor in prone).
Technique execution:
- Oscillatory force directed anteriorly on the posterior talus
- Grade I–II: Pain modulation
- Grade III: End-range oscillations for capsular stretch
- Duration: 30–60 seconds, 3–5 sets
Indications:
- Decreased plantarflexion with capsular end-feel
- Post-immobilization in dorsiflexed position
- Anterior ankle impingement symptoms (os trigonum syndrome)
Muscles Crossing This Joint
Dorsiflexors (Anterior Compartment)
Plantarflexors (Posterior Compartment)
Evertors (Lateral Compartment)
Conditions Affecting This Joint
- conditions/lateral-ankle-sprain — the most common musculoskeletal injury; inversion mechanism; ATFL first, then CFL, then PTFL
- conditions/achilles-tendinopathy — posterior ankle pain at the Achilles tendon insertion or midsubstance; worsened by dorsiflexion
- Anterior ankle impingement — bony or soft tissue impingement at the anterior joint line during dorsiflexion; talar osteophytes ("footballer's ankle")
- Ankle fracture — malleolar fractures classified by Weber system (A: below syndesmosis; B: at syndesmosis; C: above syndesmosis with syndesmotic disruption)
- Talar dome lesion (osteochondral defect) — cartilage and subchondral bone damage from ankle sprains; deep ankle pain with weight bearing; may require surgical intervention
Clinical Notes
- Dorsiflexion loss is the most functionally significant ankle restriction. Less than 10° of dorsiflexion limits normal gait, forces compensatory subtalar overpronation, increases Achilles tendon loading, and predisposes to recurrent ankle sprains. Post-sprain dorsiflexion loss is the most common modifiable risk factor for recurrent sprains.
- Ankle sprain rehabilitation must include mobilization. Research consistently shows that early mobilization (posterior talar glide) after ankle sprain reduces pain, restores dorsiflexion faster, and improves functional outcomes compared to immobilization alone. Grade I–II oscillations can begin 48–72 hours post-injury.
- Differentiate gastrocnemius from capsular dorsiflexion restriction. Test dorsiflexion with the knee extended (gastrocnemius crosses the knee — taut) and with the knee bent (gastrocnemius slack — only capsule and soleus limit motion). If dorsiflexion improves with knee flexion, the gastrocnemius is the primary restrictor. If it does not improve, the restriction is capsular or soleal.
- The ankle is more stable in dorsiflexion than plantarflexion. The wider anterior talus fills the mortise in dorsiflexion, maximizing bony stability. In plantarflexion, the narrower posterior talus allows more play — this is why most ankle sprains occur during plantarflexion (landing from a jump, stepping off a curb).
Key Takeaways
- Posterior talar glide restores dorsiflexion — the most clinically important talocrural mobilization and the most common post-sprain technique.
- The ATFL is the weakest lateral ligament and the most commonly torn ligament in the body — it fails first in the plantarflexion-inversion mechanism.
- Minimum 10° dorsiflexion is needed for normal gait — less than this produces compensatory overpronation and recurrent sprain risk.
- Always differentiate gastrocnemius restriction (improves with knee bent) from capsular restriction (does not change with knee position) before mobilizing.
