Medial Plantar Nerve: Jogger’s Foot Entrapment, Knot of Henry, and Treatment

The medial plantar nerve is the larger of the two terminal branches of the posterior tibial nerve, arising in the tarsal tunnel behind the medial malleolus and coursing along the medial plantar aspect of the foot to supply motor innervation to the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and first lumbrical, plus sensory innervation to the medial sole and the plantar surface of the medial 3.5 toes (first through the medial half of the fourth). Medial plantar nerve entrapment — also called jogger’s foot or medial plantar neuropraxia — occurs most commonly at the knot of Henry, a fibromuscular arch where the flexor hallucis longus and flexor digitorum longus tendons cross beneath the navicular, compressing the nerve in athletes with excessive pronation, hindfoot valgus, or those using orthoses with a rigid medial arch post that creates point pressure directly over this anatomical tunnel. The medial plantar nerve must be distinguished from other causes of medial plantar foot pain including plantar fasciitis, flexor hallucis longus tendinopathy, and tarsal tunnel syndrome (which involves the entire posterior tibial nerve before it divides).

Medial Plantar Nerve Entrapment: Clinical Differentiation from Similar Conditions

Feature	Medial Plantar Nerve Entrapment (Jogger’s Foot)	Tarsal Tunnel Syndrome	Plantar Fasciitis	Flexor Hallucis Longus Tendinopathy
Location of pain / numbness	Medial plantar foot along medial arch; numbness medial 3.5 toes; burning along medial sole; no heel involvement	Medial ankle behind medial malleolus; diffuse plantar foot burning; involves heel (calcaneal branch) and all toes depending on division affected	Plantar heel, medial calcaneal insertion; may radiate along medial arch; no numbness; no tingling	Posterior ankle medial side; groove behind medial malleolus; may extend along plantar hallux; no numbness
Provocative location	Knot of Henry (3 cm distal to navicular tuberosity on plantar medial foot); Tinel positive at this site; worse with push-off and pronation	Tarsal tunnel (posterior and inferior to medial malleolus); Tinel positive behind medial malleolus; worse with standing	Proximal plantar fascia at calcaneus; first-step pain worst in morning; no Tinel; worse after rest (post-static dyskinesia)	Behind medial malleolus or plantar hallux; triggering or locking of hallux (hallux saltans); pain with passive dorsiflexion of hallux
Population	Runners with hyperpronation or hindfoot valgus; athletes using rigid medial arch orthoses; dance athletes	Any age; systemic conditions (hypothyroidism, diabetes, RA); space-occupying lesions (ganglion, lipoma, varicosities); bilateral in systemic cases	Runners, overweight adults, people with tight calf musculature; bilateral in 30%; morning pain classic	Ballet dancers, athletes with repetitive push-off; posterior ankle impingement; hallux locking in flexion
Diagnosis	Tinel at knot of Henry; NCS: medial plantar sensory nerve action potential reduced; ultrasound: nerve thickening at navicular; diagnostic nerve block confirms	Tinel behind medial malleolus; NCS: posterior tibial motor and sensory latencies prolonged; MRI tarsal tunnel: space-occupying lesion	Clinical; X-ray rules out calcaneal fracture/stress; MRI if plantar fascia rupture suspected; ultrasound confirms plantar fascia thickening	MRI: FHL tendinopathy, FHL tenosynovitis, os trigonum; hallux dorsiflexion test provocative; dynamic ultrasound for tendon motion
Treatment highlights	Orthotic modification (reduce medial arch ridge height); gait retraining to reduce pronation; corticosteroid injection at knot of Henry; surgical decompression if refractory	Treat underlying cause; corticosteroid injection in tarsal tunnel; surgical tarsal tunnel release for structural causes; address systemic disease	Stretching, orthotics, cortisone, PRP; surgery (gastrocnemius recession, plantar fascia release) for recalcitrant cases	Activity modification; orthosis; corticosteroid injection in FHL sheath; os trigonum excision; FHL release if tunnel stenosis

Medial Plantar Nerve: Anatomy, Entrapment Sites, and Management Protocol

Topic	Detail
Anatomy	Arises from posterior tibial nerve in tarsal tunnel; travels under abductor hallucis muscle belly; enters foot medial to FDL tendon at knot of Henry (crossing point of FHL and FDL); supplies medial intrinsic muscles + plantar sensation medial 3.5 toes; motor to abductor hallucis, FDB, FHB (medial head), 1st lumbrical
Entrapment sites	Primary: Knot of Henry — fibromuscular arch where FHL crosses FDL at navicular level, 3 cm distal to medial malleolus; Secondary: under abductor hallucis fibromuscular origin; Tertiary: at medial calcaneal tubercle fascial edge (less common)
Biomechanical risk factors	Hyperpronation and hindfoot valgus — excessive medial arch collapse repetitively stretches nerve over bony arch; rigid orthotic medial post pressing directly on knot of Henry; rapid training volume increase in runners; intrinsic muscle hypertrophy compressing nerve
Conservative treatment	Step 1: Orthotic modification — reduce medial arch height to relieve direct pressure; add cutout at knot of Henry site. Step 2: Activity modification — reduce mileage, avoid camber running. Step 3: Gait retraining — reduce pronation. Step 4: Physical therapy — eccentric peroneal and tibialis posterior strengthening. Step 5: Ultrasound-guided corticosteroid injection perineural at knot of Henry (not intraneural)
Surgical decompression	Release of abductor hallucis fibromuscular arch; decompression of FHL/FDL crossover at knot of Henry; indicated when conservative care fails after 3-6 months; 75-85% good results; open or endoscopic technique; protect medial calcaneal branch during surgery

At Balance Foot & Ankle in Howell and Bloomfield Hills, medial arch burning in runners with hyperpronation that is worsened by a rigid arch orthosis prompts evaluation for medial plantar nerve entrapment at the knot of Henry — orthotic modification (reducing the arch height and adding a relief cutout at the navicular) often resolves jogger’s foot without injection or surgery. Call (810) 206-1402.