Baxter neuropathy is a nerve entrapment syndrome resulting from the compression of the inferior calcaneal nerve (Baxter nerve).
- heel pain with maximal tenderness over the course of the inferior calcaneal nerve (on the plantar medial aspect of the foot and anterior to the medial aspect of the calcaneus)
- paraesthesia with motor weakness of the abductor digiti minimi muscle
- no associated cutaneous sensory deficit
There are three sites of possible entrapment:
- deep to or adjacent to the fascial edge of a hypertrophied abductor hallucis muscle
- along the medial edge of the quadratus plantae muscle
- adjacent to the medial calcaneal tuberosity
Predisposing factors include:
- muscle hypertrophy
- hyperpronated foot
- flat foot
- calcaneal enthesophyte: plantar calcaneal spur
- plantar fasciitis
- seronegative spondyloarthropathies
Acute phase of muscle denervation
Affected region shows decreased signal intensity on T1 and increased signal intensity on T2 with fat-saturation due to increased extracellular water content and decreased muscle fiber volumes of the involved muscles innervated by the inferior calcaneal nerve.
Chronic phase of muscle denervation
Signs of amyotrophy or fatty degeneration of the abductor digiti minimi muscle and less commonly of the flexor digitorum brevis and the quadratus plantae muscles.
Treatment and prognosis
The treatment is generally via a non-surgical approach (e.g. glucocorticoid injections), however surgery can be performed if refractory to non-surgical approaches.
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