Heel pain is one of the most common complaints in musculoskeletal medicine, and for decades, plantar fasciitis has dominated both diagnosis and treatment. Yet a significant proportion of patients fail to improve with standard care. For these individuals, the true culprit often lies deeper—a small but critical nerve known as Baxter’s nerve. Baxter’s neuritis, or entrapment of the first branch of the lateral plantar nerve, represents a frequently overlooked cause of chronic heel pain that can mimic and coexist with plantar fasciitis, leading to misdiagnosis and ineffective treatment.

Anatomy and Pathophysiology

Baxter’s nerve is a small, mixed sensory and motor nerve—approximately 2 mm in diameter—that arises from the lateral plantar nerve within the tarsal tunnel. It courses vertically between the abductor hallucis and quadratus plantae muscles before making a horizontal turn beneath the calcaneus to innervate the abductor digiti minimi muscle and provide sensory innervation to the calcaneal periosteum and long plantar ligament . This complex anatomical course makes the nerve vulnerable to compression at two primary sites: where it passes between the fascial planes of the abductor hallucis and quadratus plantae muscles, and where it crosses anterior to the medial calcaneal tuberosity or a plantar calcaneal spur .

The condition was first characterized by Dr. Donald Baxter, who recognized that compression of this nerve could produce symptoms distinct from plantar fasciitis. Because the nerve travels through such a narrow corridor, any space-occupying lesion or biomechanical alteration can compromise its function. Common causes include plantar fasciitis with associated thickening, calcaneal spurs, hypertrophy of the abductor hallucis muscle, and excessive pronation with flatfoot deformity . The resulting compression disrupts the nerve’s blood supply and leads to neurogenic inflammation, producing the characteristic burning pain and, in chronic cases, motor weakness affecting the fifth toe .

Clinical Presentation and Diagnostic Challenges

Baxter’s neuritis is responsible for approximately 15–20% of chronic heel pain cases, yet it remains underdiagnosed because its symptoms overlap substantially with plantar fasciitis . The key distinguishing feature lies in the character and timing of pain. While plantar fasciitis classically produces sharp, stabbing pain that is worst with the first steps in the morning and improves with activity, Baxter’s neuritis tends to cause burning or aching pain that worsens with weight-bearing activity as the day progresses . Patients may also report tingling, numbness, or radiating discomfort along the medial heel and lateral aspect of the foot .

Diagnosis remains challenging because no single test is definitive. Physical examination may reveal tenderness over the course of the nerve, and passive eversion or abduction of the foot can reproduce symptoms . Plain radiographs are typically unremarkable, though they may reveal a calcaneal spur. Magnetic resonance imaging has emerged as the imaging modality of choice, with isolated atrophy and fatty infiltration of the abductor digiti minimi muscle serving as a highly characteristic sign of chronic Baxter’s neuropathy . High-resolution ultrasound is increasingly valuable for both diagnosis and image-guided procedures, though the nerve itself may not always be clearly visualized .

Treatment Approaches

Management of Baxter’s neuritis typically begins with conservative measures aimed at reducing nerve irritation and addressing underlying biomechanical contributors. Activity modification, appropriate footwear with adequate cushioning and arch support, and orthotic therapy can be effective in selected patients, particularly those with excessive pronation . Physical therapy focused on strengthening the intrinsic foot muscles and improving ankle mechanics may help reduce abnormal loading patterns.

For patients who do not respond to conservative care, image-guided interventions offer promising alternatives. Ultrasound-guided local anesthetic blocks can serve both diagnostic and therapeutic purposes, with immediate pain relief supporting the diagnosis . Corticosteroid injections adjacent to the nerve have been used traditionally, though concerns about long-term steroid effects have prompted interest in alternatives. Ultrasound-guided hydrodissection—injecting fluid to separate the entrapped nerve from surrounding fascial planes—has shown dramatic and sustained relief in case reports, with 5% dextrose emerging as a safe injectate that avoids steroid-related risks . Surgical decompression, involving release of the deep fascia of the abductor hallucis muscle and removal of any impinging structures, is reserved for refractory cases .

Baxter’s neuritis represents a significant yet frequently missed cause of chronic heel pain. Its clinical overlap with plantar fasciitis means that many patients receive treatment directed at the wrong structure, prolonging suffering and delaying recovery. Clinicians should maintain a high index of suspicion in patients whose heel pain fails to respond to standard plantar fasciitis management, particularly when burning pain, progressive worsening with activity, or lateral foot symptoms are present. Advanced imaging, especially MRI demonstrating abductor digiti minimi atrophy, can confirm the diagnosis. With appropriate treatment—ranging from conservative measures to ultrasound-guided interventions—most patients can achieve meaningful relief. Recognizing Baxter’s nerve as a hidden culprit ensures that heel pain is treated at its true source rather than managed as a condition it is not.