Heel pain is one of the most common musculoskeletal complaints, with plantar fasciitis affecting approximately 10% of the population at some point in their lives. While often labeled as an inflammatory “itis,” chronic plantar fasciitis is more accurately described as plantar fasciosis—a degenerative process involving microtears and collagen breakdown at the calcaneal attachment. For the board-certified physician, success depends on identifying the “first step” history, assessing for foot-type predispositions, and ruling out Baxter’s nerve entrapment.

1. Functional Anatomy: The “Windlass Mechanism”

The plantar fascia is a thick, fibrous band of connective tissue that originates from the medial tubercle of the calcaneus and inserts into the proximal phalanges of the toes.

• Arch Support: The fascia acts as a primary stabilizer of the medial longitudinal arch.
• The Windlass Effect: As the great toe is dorsiflexed (as in the “toe-off” phase of gait), the plantar fascia is pulled taut around the metatarsophalangeal joints, which shortens the distance between the calcaneus and the toes. This elevates the arch and converts the foot into a rigid lever for propulsion.

2. Clinical Presentation: “The First Step”

The hallmark of plantar fasciitis is pain localized to the inferior-medial aspect of the heel.

• Post-Static Dyskinesia: Pain is most severe with the first few steps in the morning or after prolonged sitting. The fascia “contracts” during rest (plantarflexion), and the sudden stretch of weight-bearing causes micro-trauma to the degenerative tissue.
• Activity Patterns: Pain often improves with initial activity but worsens after prolonged weight-bearing or at the end of the day.

3. Physical Examination and Provocative Testing

• Point Tenderness: Maximal tenderness is elicited by deep palpation over the medial calcaneal tubercle.
• Windlass Test: Passive dorsiflexion of the great toe while the patient is weight-bearing. This should reproduce the heel pain.
• Check for Gastroc-Soleus Tightness: Limited ankle dorsiflexion (tight calves) is a major risk factor, as it increases the tensile load on the plantar fascia through the “Achilles-calcaneal-plantar” functional unit.

4. Differential Diagnosis: The Mimics

A high-yield board concept is recognizing when heel pain is not plantar fasciitis.

• Baxter’s Nerve Entrapment: Compression of the first branch of the lateral plantar nerve. Pain is often indistinguishable from plantar fasciitis, but tenderness is more lateral and may include paresthesia.
• Calcaneal Stress Fracture: Pain is typically more diffuse and elicited by the “Squeeze Test” (compressing the calcaneus from both sides). Unlike plantar fasciitis, this pain is present during rest and constant weight-bearing.
• Fat Pad Atrophy: Common in the elderly. Pain is felt directly over the center of the heel rather than the medial tubercle and is exacerbated by walking barefoot on hard surfaces.
• Tarsal Tunnel Syndrome: Compression of the posterior tibial nerve. Pain is accompanied by numbness or tingling in the sole of the foot and a positive Tinel’s sign behind the medial malleolus.

5. Interventional Management

• Corticosteroid Injections: Provides effective short-term relief. However, a significant board-relevant risk is plantar fascia rupture or fat pad atrophy if injections are repeated too frequently.
• Extracorporeal Shockwave Therapy (ESWT): A non-invasive option for chronic cases. It uses acoustic waves to induce microtrauma, theoretically stimulating a healing response in the degenerative fascia.
• Platelet-Rich Plasma (PRP): Emerging evidence suggests PRP may be superior to steroids for long-term resolution by addressing the underlying “fasciosis.”

6. The Biomechanical “Reset”

The treatment of plantar fasciitis is focused on stretching and mechanical support.

• Night Splints: These hold the foot in a neutral or slightly dorsiflexed position overnight, preventing the fascia from contracting and reducing the “first-step” pain in the morning.
• Intrinsic Muscle Strengthening: “Towel curls” or “marble pickups” with the toes help strengthen the small muscles of the foot, reducing the load on the fascia.
• Orthotics: For patients with Pes Planus (flat feet) or Pes Cavus (high arches), a medial longitudinal arch support can redistribute the forces during the gait cycle.

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High-Yield Board “Fast Facts”

• Medial Calcaneal Tubercle: The most common site of tenderness.
• Baxter’s Nerve: The first branch of the lateral plantar nerve; the most common neurological mimic.
• Windlass Mechanism: Passive great toe extension tautens the fascia.
• Morning Pain: The most specific historical finding.
• Heel Spurs: Often seen on X-ray but poorly correlated with pain; many symptomatic patients have no spurs, and many asymptomatic patients have large ones.