A patient presents with pain on the inferior medial heel, worse when initiating activity with tenderness to palpation. Your first thought is plantar fasciitis, but have you ever considered Baxter’s Neuropathy? Baxter’s neuropathy results from compression of the inferior calcaneal nerve and entrapment may result in pain that is indistinguishable from plantar fasciitis.
ChiroUp advisor Dr David Flatt presented an outstanding synopsis of this presentation at a conference earlier this month. A quick search of the literature finds that this condition is more prevalent than one might imagine. In fact, a recent study from Brazil found:
One of the most common causes of chronic pain is entrapment of the first branch of the lateral plantar nerve, a condition that is known as Baxter’s neuropathy. It is believed that approximately 20% of cases of pain in the medial region of the heel are associated with neuropathy of that nerve. (1)
Clinically distinguishing Plantar fasciitis from Baxter’s neuropathy can pose a challenge. Neurologic evaluation is the key to establishing the correct diagnosis. Since the first branch of the lateral plantar nerve supplies a motor component to the abductor digiti minimi muscle, one possible differentiating factor is a subtle loss of fifth digit abduction. All patients with plantar fasciitis symptoms should be asked to abduct their 5th digit, i.e., “spread your toes”. Patients who are suffering from entrapment of the lateral plantar nerve (Baxters Neuropathy) may have difficulty performing this task. Additionally, the pain of Baxter’s neuritis may be provoked via neurologic traction ischemia by abducting and dorsiflexing the forefoot for 30-60 seconds. (2)
The Brazilian study suggests that MRI evaluation is appropriate to establish a diagnosis of Baxter’s Neuropathy in heel pain patients with abductor digiti minimi weakness:
Magnetic resonance imaging (MRI) may be used to detect alterations associated with Abductor Digiti Minimi muscle denervation. The presence of such a muscle atrophy observed at MRI reflects a chronic compression of the inferior calcaneal nerve and contributes to the clinical diagnosis of Baxter’s neuropathy. (1)
However, not all heel pain patients require MRI evaluation:
Initially, heel pain should be treated with conservative measures (footwear modification, orthotics, anti-inflammatory modalities, etc) As the pain becomes chronic, without any improvement with the conservative treatment, the hypothesis of compression of the first branch of the lateral plantar nerve should be considered. Patients who are suffering from a compressive neuropathy may benefit from surgical decompression of the region. (1)
The bottom line: “Plantar fasciitis” patients who are unable to abduct their 5th digit should have MRI and possible neurosurgical consult, all others should start with traditional conservative care.
1. Rodrigues RN, Lopes AA, Torres JM, Mundim MF, Silva LLG, Silva BR de C e. Compressive neuropathy of the first branch of the lateral plantar nerve: a study by magnetic resonance imaging. Radiologia Brasileira. 2015;48(6):368-372.
2. Trinh KH, et al. Expert Opinion: A Review of the Evaluation and Treatment of Heel Pain. Practical Neurology.com June 2015. Accessed 3/15/16.
About the Author
Dr. Tim Bertelsman
DC, CCSP, DACO
Dr. Tim Bertelsman graduated with honors from Logan College of Chiropractic and has been practicing in Belleville, IL since 1992. He has lectured nationally on various clinical and business topics and has been published extensively. He has served in several leadership positions within the Illinois Chiropractic Society and currently serves as President of the executive board.
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