2026 Workshop Handout Bundle-W35F - Needle EMG of the Foot

W35F - Needle EMG of the Foot - Park

Pdf Summary

The article describes the anatomy, technique, and clinical interpretation of needle EMG examination of intrinsic foot muscles, particularly when evaluating suspected nerve entrapment. These muscles may also be affected by polyneuropathy, radiculopathy, or plexopathy, so findings must be interpreted in the broader clinical context.<br /><br />Most intrinsic foot muscles are supplied by branches of the tibial nerve: the medial plantar nerve (MPN), lateral plantar nerve (LPN), and Baxter’s nerve. The extensor digitorum brevis (EDB) is supplied by the deep peroneal nerve. The article reviews potential compression sites, including the tarsal tunnel, plantar nerve canals, and sites along Baxter’s nerve; Baxter’s nerve is described as a frequent source of heel pain and entrapment.<br /><br />Practical guidance is provided for examining selected muscles: the first and fourth dorsal interossei, flexor digiti minimi brevis, abductor digiti quinti, abductor hallucis, and EDB. Needle placement is based on surface landmarks and muscle-specific movements that help confirm correct positioning.<br /><br />The authors address concerns about pain and abnormal findings in healthy people. Mild insertional activity alone should be interpreted cautiously; sustained fibrillation potentials or positive sharp waves are more persuasive evidence of denervation. Comparing the same muscle in the opposite foot can help distinguish focal abnormalities from background changes.<br /><br />A single muscle, such as the abductor hallucis, is inadequate to screen for tarsal tunnel syndrome because individual nerve branches may be compressed farther along their course. Muscle selection should account for symptom patterns and possible involvement of other nerves. When indicated, examination should extend to other foot muscles, proximal limb muscles, the opposite foot, and lumbosacral paraspinals. Ultimately, EMG results should be integrated with the history, examination, and nerve conduction studies.

Keywords

needle EMG

intrinsic foot muscles

tarsal tunnel syndrome

nerve entrapment

tibial nerve

medial plantar nerve

lateral plantar nerve

Baxter's nerve

extensor digitorum brevis

denervation