Baxter's Neuritis: A Plantar Fasciitis Mimic

Quick answer

Baxter’s neuritis is compression of a small nerve deep in the heel — the first branch of the lateral plantar nerve, often called “Baxter’s nerve” after Dr. Donald Baxter, who described the entrapment in the 1980s. The nerve gets pinched as it passes between two muscles near the heel bone, producing pain that looks and feels a lot like plantar fasciitis but doesn’t fully respond to standard fasciitis treatment.

It’s estimated to account for 15 to 20 percent of chronic heel pain cases, particularly the ones that get labeled “treatment-resistant plantar fasciitis.” Identifying it changes the treatment plan in meaningful ways.

Why this page exists

Plantar fasciitis is the most common cause of chronic heel pain — but it’s not the only one, and not every “plantar fasciitis” actually is. The classic story of plantar fasciitis is sharp morning heel pain that improves once you warm up, then worsens at the end of the day. When heel pain doesn’t follow that pattern — when it burns, radiates, gets worse with activity rather than better, or fails to improve after 6 to 8 weeks of proper conservative care — Baxter’s neuritis is one of the conditions that needs to be ruled out.

What’s actually happening

The lateral plantar nerve branches off the tibial nerve and runs along the bottom of the foot. Its first branch (the one named for Baxter) takes a sharp turn deep in the heel and threads between two small muscles:

• Abductor hallucis above (the muscle that runs along the inside of the foot)
• Quadratus plantae below (a deep heel muscle)

In this tight tunnel, the nerve can get compressed by:

• The deep fascia of the abductor hallucis itself, which is stiff and unforgiving
• Local inflammation from adjacent plantar fasciitis or heel spur
• Mechanical overload from overpronation, flat feet, or repetitive impact
• Bony prominence at the medial calcaneal tubercle pressing against the nerve

After Baxter’s nerve passes this tight zone, it supplies the abductor digiti minimi (the small muscle on the outside of the foot). When the nerve is compressed long enough, this muscle starts to atrophy — a finding that becomes visible on MRI and helps confirm the diagnosis.

How to recognize it

Baxter’s neuritis often hides as “stubborn plantar fasciitis.” The clues that point toward nerve involvement instead of pure fasciitis:

• Burning, electric, or radiating quality to the pain, rather than the sharp focal pain of fasciitis
• Tenderness slightly more medial and lower than the classic plantar fasciitis tender spot — about a thumb’s width below and behind the front of the heel
• Pain that worsens with activity rather than improving as you walk it off
• Pain that doesn’t have the classic “first step in the morning” pattern — or has it weakly
• Radiation into the arch or lateral foot, not just the heel
• No improvement after 6 to 8 weeks of stretching, supportive shoes, and other plantar fasciitis care
• Numbness or tingling in the outside of the foot (suggests motor or sensory involvement of the nerve)

Many patients describe Baxter’s neuritis as feeling like “plantar fasciitis that has a different personality” — same general area, different quality, doesn’t respond to the usual fixes.

How plantar fasciitis and Baxter’s neuritis compare

The two can coexist, which complicates the picture — that’s part of why this diagnosis is missed so often.

Diagnosis

The diagnosis is clinical in most cases. A foot and ankle specialist evaluates:

• History — what makes the pain better and worse, how long it has been present, what treatments have been tried
• Palpation — tenderness exactly over the course of the nerve (not over the plantar fascia origin)
• Provocative maneuvers — stretching the abductor hallucis or compressing the nerve can reproduce symptoms
• Neurological exam — looking for weakness or sensory changes in the outside of the foot

When imaging is helpful:

• MRI — the most useful test. Atrophy or fatty replacement of the abductor digiti minimi is the signature finding (visible on T1-weighted images as the muscle being replaced by bright fat signal) and is roughly 90 percent specific for chronic Baxter’s nerve entrapment when present
• Ultrasound — can visualize the nerve and the local soft tissue, and is sometimes used to guide injections
• Nerve conduction studies — technically difficult for this small nerve; rarely changes management

Treatment

The first-line treatment overlaps significantly with plantar fasciitis care, because reducing strain on the surrounding tissue also reduces pressure on the nerve.

Conservative care (first 3 to 6 months)

• Calf and plantar fascia stretching — daily, both straight-knee and bent-knee gastroc/soleus stretches plus a plantar fascia-specific stretch (pulling the toes back manually)
• Supportive shoes with a stiff midsole and contoured arch support — reduces overload on the heel
• Custom orthotics or quality over-the-counter inserts (Powerstep, Superfeet) with a heel cup and arch support — addresses overpronation and offloads the area where the nerve is being compressed
• Activity modification — temporary reduction in high-impact activities; replace with cycling, swimming, or pool running
• NSAIDs in short courses if no contraindication
• Address tight calves — calf tightness loads the entire heel and worsens both plantar fasciitis and nerve compression

When conservative care fails

If symptoms have not improved meaningfully after 3 to 6 months of consistent conservative care, options include:

• Ultrasound-guided corticosteroid injection at the nerve — this is a different injection technique than the standard plantar fasciitis injection, requiring precise placement to deliver medication around the nerve rather than into the plantar fascia
• Surgical decompression — for refractory cases. The procedure involves releasing the deep fascia of the abductor hallucis (and sometimes a portion of the inferior border of the abductor itself) to relieve pressure on the nerve. Recovery is roughly 4 to 6 weeks in a walking boot, with most patients returning to full activity by 3 months. Success rates of 70 to 90 percent are reported in published series

What does NOT typically help

• Repeated standard plantar fasciitis injections that miss the nerve location — these may temporarily reduce surrounding inflammation but don’t address the actual nerve compression
• Night splints — useful for plantar fasciitis but generally do not change Baxter’s neuritis symptoms
• Shockwave therapy — limited evidence specifically for nerve compression; mostly studied for plantar fasciitis itself

When to see a clinician

• Heel pain that hasn’t improved after 6 to 8 weeks of proper plantar fasciitis treatment (stretching, orthotics, supportive shoes)
• Burning or radiating quality to your heel pain
• Pain that worsens with activity instead of improving once you warm up
• Numbness or tingling in the outside of your foot
• Persistent heel pain with no morning-pain pattern, or where the morning-pain pattern is weak
• Heel pain in someone with diabetes or other risk factors for neuropathy — always warrants prompt evaluation

Bottom line

Baxter’s neuritis is one of the most commonly missed causes of chronic heel pain because it sits anatomically right next to the plantar fascia and shares many treatment overlaps with plantar fasciitis. The single most useful step is recognizing when standard plantar fasciitis treatment isn’t working and considering whether a nerve compression is contributing. Most cases improve with conservative care; the small subset that don’t usually respond well to targeted injection or surgical decompression. This page is general educational information; the diagnosis and treatment plan need to come from a clinician who has examined your foot.