Baxter's Nerve Impingement and Other Neuropathies of the Foot: Implications for Physical Therapy
Authors: Hornick Brandon J. , Amabile Amy H. 
Published: November 2023

Introduction/Objective

Compression neuropathies of the foot and ankle occur frequently in athletes and individuals wearing tight shoes. As compression neuropathies are often misdiagnosed, understanding the musculature and neural distributions within the foot and ankle can ultimately lead to more accurate diagnoses. The objective of this report was to describe our findings during cadaver dissection, discuss the etiology of compression neuropathies, and to identify the implications for direct access physical therapy management.

Case Report/Description of Dissection

The subject was a 66 year‐old male with a cause of death of glioblastoma. The initial dissection was conducted as described by Grant. After removing the skin from the foot and leg, the plantar aponeurosis, flexor digitorum brevis and abductor hallucis muscles were transected and reflected distally, revealing the medial and lateral plantar neurovascular bundles. The inferior calcaneal (Baxter's) nerve was identified as it branched off of the lateral plantar nerve inferior to the medial malleolus and deep to the flexor digitorum brevis. An anatomic anomaly was discovered with an early branching, proximal to the tarsal tunnel, of the lateral plantar nerve to the abductor hallucis muscle.

Discussion

Entrapment of nervous tissue within the foot may be caused secondary to space‐occupying lesions, tenosynovitis, accessory or hypertrophic musculature, bony spurs, and even bursitis. Trauma, tight or high‐heeled shoes, systemic diseases such as diabetes, and faulty running mechanics may also be responsible for nerve compression. Baxter's impingement is thought to be responsible for up to 20% of heel pain, however it is often misdiagnosed as plantar fasciitis. The prevalence of heel pain in adults is close to 15%, and with similar presentations to compression neuropathies, misdiagnoses are often encountered. Runners that place their metatarsal arches in excessive hyperextension (Morton's neuroma) or repetitive eversion/pronation (jogger's foot and Baxter's neuropathy) are at a higher risk for compression neuropathies. MRI, radiographs, ultrasonography and nerve conduction velocity testing have been utilized to enhance the diagnoses of compression neuropathies. With this technology, the source behind a patient's symptoms including the potential severity, location and root cause of possible impingement can be identified reliably.

Clinical Considerations/Conclusions

Physical therapists should be aware of the typical presentation of neural involvement which includes burning, sharp, shooting pain that can be accompanied by weakness and sensory changes. Also a comprehensive history and special testing that places stress on the neural tissues of the foot may help to identify compression neuropathies. Imaging may be, but is not always, necessary. Conservative management can include rest, NSAIDs, orthotics, shoe‐wear modifications, cryotherapy, avoidance of flat shoes and heels, Achilles and plantar fascia stretching, and night splints. When conservative approaches fail to provide symptom relief after 6 weeks to 12 months, surgical interventions, including excision of nerve, ligament or osteophytes, as well as fasciotomies, may be warranted.