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Anatomy and Clinical Examination of the Ankle Joint

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PART 1: ANATOMY OF THE ANKLE JOINT

1. Bony Architecture - The Ankle Mortise

• Talocrural joint (true ankle joint) - a synovial hinge joint between the tibia, fibula, and talus
• Subtalar (talocalcaneal) joint - articulation between talus and calcaneus, allowing inversion/eversion

• Tibial plafond (tibial articular surface) - the roof
• Medial malleolus (distal tibia) - the medial wall
• Lateral malleolus (distal fibula) - the lateral wall, extending ~1 cm more distally than the medial malleolus

Source: Miller's Review of Orthopaedics, 9th Ed., p. 193; ROSEN's Emergency Medicine, p. 828

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2. The Distal Tibiofibular Joint (Syndesmosis)

Source: Miller's Review of Orthopaedics, 9th Ed., p. 193

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3. Ligaments of the Ankle

Medial (Deltoid) Ligament

• Superficial layer (crosses both ankle AND subtalar joint):
  • Tibionavicular part
  • Tibiocalcaneal part
• Deep layer (crosses ankle joint only):
  • Anterior tibiotalar part
  • Posterior tibiotalar part

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Lateral Ligament Complex

• Plantarflexion + inversion → stresses ATFL
• Neutral + inversion → stresses CFL

Source: Miller's Review of Orthopaedics, 9th Ed., p. 183-184

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4. Subtalar Joint

1. Medial ligament
2. Lateral ligament
3. Interosseous talocalcaneal ligament
4. Cervical ligament

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5. Key Intertarsal Ligaments

Source: Miller's Review of Orthopaedics, 9th Ed., p. 204-213

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6. Muscles Acting on the Ankle

Source: Miller's Review of Orthopaedics, 9th Ed., p. 194

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7. Range of Motion

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 518; S. Das Manual on Clinical Surgery

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PART 2: CLINICAL EXAMINATION OF THE ANKLE JOINT

LOOK (Inspection)

1. Overall alignment - assess pelvic obliquity, leg-length discrepancy, valgus/varus at the knee, rotational alignment
2. Foot shape from all three planes:
   • Front view: overall forefoot shape
   • Lateral view: medial longitudinal arch (normal = visible arch), note pes planus (collapsed arch) or pes cavus (high arch)
   • Posterior view: heel position; normal heel valgus is 5-7°; count toes visible from behind - the "too many toes" sign indicates forefoot abduction (pes planus)
3. Skin: look for bunions (medial MTP swelling/bursa), gouty tophi, thin fat pads (rheumatoid), corns, callositites, nail changes, ulcers, sinuses
4. Soft tissue swelling: indicates joint or soft tissue pathology
5. Muscle wasting: commonly on the dorsum of foot and between metatarsal heads (neurological cause)
6. Bony prominences/exostoses

• High-stepping gait = foot drop (common peroneal nerve palsy)
• Antalgic gait = ankle/foot joint pain
• Short propulsive phase = forefoot pain

• External: normal heel wear is posterolateral corner; circular wear under 1st MTP = toe-off
• Internal: insoles, arch supports, heel cups

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 516-517

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FEEL (Palpation)

• Posterior tibial pulse (behind medial malleolus) and dorsalis pedis pulse (dorsum of foot, lateral to EHL tendon)
• Tibialis anterior tendon and long extensor tendons on the dorsum
• Achilles tendon from the back - feel for gaps (rupture), tenderness, swelling; identify Haglund's prominence posterolateral on calcaneus and retro-Achilles bursa
• Peroneal tendons from the lateral side
• Tibialis posterior tendon from the medial side
• Sinus tarsi - soft-tissue depression anterior to the lateral malleolus; tenderness here with subjective instability = sinus tarsi syndrome

• Ankle joint: medial and lateral malleoli, anterior and posterior joint line, lateral gutter and ligament complex, syndesmosis (front of ankle), medial gutter and deltoid ligament
• Subtalar joint: palpate each facet
• Midtarsal joints: talonavicular and calcaneocuboid joints
• Tarsometatarsal joints (TMTJ): note the 2nd TMTJ is several mm proximal to the others
• Calcaneus: most common cause of heel pain is plantar fasciitis - burning/electric shock pain worst in morning
• Sustentaculum tali: palpate one fingerbreadth below the medial malleolus (attachment of spring ligament)
• Head of talus: invert and evert the patient's foot while palpating
• Cuneiforms, MTPJs, web spaces

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 517; S. Das Manual on Clinical Surgery, p. 325

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MOVE (Examination of Range of Motion)

• PAED = Pronation, Abduction, Eversion, Dorsiflexion
• SAPI = Supination, Adduction, Plantarflexion, Inversion

• Dorsiflexion (normal ~20°): test with knee both flexed and extended
  • Restriction greater with knee extended = gastrocnemius contracture
  • Equal restriction in all knee positions = soleus contracture
• Plantarflexion (normal ~15° touching floor): weakness suggests Achilles injury or S1 nerve root pathology

• Hold the talar neck, ask the patient to move their heel side to side
• Apply varus/valgus stress while feeling for movement
• Holding the talus (not the tibia) isolates subtalar from ankle motion
• Inversion (foot towards body) and Eversion (foot away from body)

• Hold heel with one hand, move forefoot medially (adduction = 20°) and laterally (abduction = 10°)

• Hold midfoot, manipulate each metatarsal up and down (passive range)

• Extension: ask patient to lift toes to ceiling (normal 70-90°)
• Flexion: point toes to floor (normal 45°)
• Normal toe-off requires 35-40° of dorsiflexion

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 518; S. Das Manual on Clinical Surgery, p. 325

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SPECIAL TESTS

1. Thompson / Simmonds Test (Achilles Tendon Integrity)

• Lie patient prone with calves resting over examiner's forearms
• Squeeze each calf in turn and watch for plantar flexion at ankle
• Lack of movement = Achilles tendon rupture
• Note: standing on tiptoes alone does NOT rule out rupture (long toe flexors can compensate)

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 519

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2. Subtalar Joint Flexibility

• Patient stands on a 2-cm block with the great toe over the medial edge resting on the floor
• Observe hindfoot from behind
• Hindfoot varus persists → subtalar joint is fixed
• Hindfoot corrects to valgus → subtalar joint is mobile

• Ask patient to stand on their toes and observe medial arch
• Arch forms immediately on tiptoe = flexible flat foot
• Failure to form = fixed flat foot

• With patient standing, lift up the great toe
• Arch forms = flexible flat foot

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 519

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3. Ankle Stability Tests

• Foot resting over the edge of the bed in slight plantarflexion
• One hand holds the heel; other hand holds the front of the tibia
• Draw the heel forwards on the fixed tibia
• Compare both sides - excessive anterior translation = ATFL insufficiency

• Hold the talus at the neck (not the heel) - this isolates the ankle from the subtalar joint
• Apply inversion stress
• Excessive tilt compared to opposite side = CFL +/- ATFL tear

• Compress the proximal calf (at mid-leg level)
• Pain elicited at the ankle = disruption of the distal tibiofibular syndesmosis ("high-ankle sprain")
• Instability of the syndesmosis may also be palpable on the anterior drawer test

Source: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 519-520

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4. Tibialis Posterior Integrity Test

• Ask patient to perform a single-foot tiptoe test on both sides
• Inability to raise heel off the ground = tibialis posterior tendon injury/insufficiency
• To test strength: position foot in plantarflexed + inverted position; apply resistance

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5. Tibialis Anterior Test

• Ask patient to walk on heels with feet inverted - tibialis anterior tendon becomes prominent
• Ask patient to dorsiflex and invert foot against resistance
• Foot drop (inability to dorsiflex) = stroke, spinal injury, spinal stenosis, L4-L5 disc prolapse, common/deep peroneal nerve injury, or peripheral neuropathy

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6. Peroneal Tendons

• Peroneal tendon dislocation: attempt to dislocate tendons by dorsiflexing and everting the foot
• Peroneus longus: ask patient to plantar flex the first metatarsal; test with active/resisted eversion

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7. Morton's Neuroma (Metatarsal Web Space)

• Palpate in the web space between 3rd and 4th toes for a mass
• Mulder's click: metatarsal compression may elicit an audible/palpable click between bones

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SUMMARY BOX: Ankle and Foot Examination Checklist

Sources: Bailey and Love's Short Practice of Surgery, 28th Ed., p. 516-521; Miller's Review of Orthopaedics, 9th Ed., p. 193-213; S. Das Manual on Clinical Surgery, 13th Ed., p. 325; General Anatomy and Musculoskeletal System (Thieme Atlas), p. 483