Plantar Fasciitis vs Tarsal Tunnel vs S1 Radiculopathy: Heel Pain Causes
Movement Dysfunction · 7 min read · 2026-01-31
Introduction
Heel pain is one of the most common foot complaints. While plantar fasciitis accounts for the majority of cases, two important differentials — tarsal tunnel syndrome and S1 radiculopathy — are frequently overlooked. Misdiagnosis leads to failed conservative treatment and frustrated patients.
Plantar Fasciitis
Pathology: Degenerative changes at the plantar fascia insertion on the medial calcaneal tuberosity.
Pain pattern: Sharp, stabbing pain at the medial heel. Worst with the first steps in the morning or after prolonged sitting. Improves with activity, worsens again at end of day.
Examination: Point tenderness at the medial calcaneal tuberosity. Pain with passive dorsiflexion of the toes (windlass test). No neurological deficits.
Key feature: The "first-step" pattern is nearly pathognomonic.
Tarsal Tunnel Syndrome
Pathology: Compression of the posterior tibial nerve as it passes behind the medial malleolus beneath the flexor retinaculum (laciniate ligament).
Pain pattern: Burning, tingling, or numbness on the plantar surface of the foot. May radiate to the toes. Symptoms often worsen with prolonged standing or walking and can be present at night.
Examination: Tinel's sign at the tarsal tunnel (tapping behind the medial malleolus reproduces tingling). Sensory changes on the sole. Possible weakness of toe flexors and intrinsic foot muscles.
Key feature: Neurological symptoms (tingling, burning, numbness) distinguish this from mechanical heel pain.
S1 Radiculopathy
Pathology: S1 nerve root compression, usually from a disc herniation at L5–S1.
Pain pattern: Pain radiates from the buttock down the posterior thigh and calf to the heel and lateral foot. The heel pain is part of a larger pain pattern, not an isolated complaint.
Examination: Reduced ankle jerk reflex. Weakness of plantarflexion and eversion. Positive straight leg raise (SLR). Sensory loss over the lateral foot and sole.
Key feature: The ankle reflex is the critical differentiator. It is normal in plantar fasciitis and tarsal tunnel syndrome but reduced or absent in S1 radiculopathy.
Comparison
Clinical Pearl
Always check the ankle jerk reflex in any patient with heel pain. It takes five seconds and immediately identifies the small percentage of patients whose heel pain is actually S1 radiculopathy. This simple test prevents unnecessary courses of plantar fasciitis treatment.
Summary
First-step pain at the medial heel = plantar fasciitis. Burning/tingling on the sole with positive Tinel's = tarsal tunnel. Heel pain with reduced ankle reflex and radiating leg pain = S1 radiculopathy.