2024 Workshop Handout Bundle-W35AS Needle EMG of the Foot Park and Del Toro

W35AS Needle EMG of the Foot Park and Del Toro

Pdf Summary

The document "Needle EMG of the Foot" by Tracy A. Park, MD, and David R. Del Toro, MD, focuses on needle electromyography (EMG) examinations for the foot's intrinsic muscles, specifically within the context of diagnosing entrapment neuropathies. These neuropathies can affect the sciatic, deep peroneal, and tibial nerves and reflect broader neurogenic disorders like peripheral polyneuropathy and lumbosacral radiculopathy/plexopathy.<br /><br />Main barriers to the widespread use of needle EMG for foot muscles include historical reports of abnormal insertional activity in normal subjects, perceptions about the procedure being more painful in the foot than in the hand, and a lack of familiarity among electrodiagnostic (EDX) consultants. The workshop aims to address these issues by enhancing understanding in anatomy, the electrophysiologic approach, technique, and clinical interpretation of needle EMG for the foot.<br /><br />The anatomy section elaborates on the innervation of foot muscles, primarily by branches of the tibial nerve (medial plantar nerve, lateral plantar nerve, and Baxter’s nerve) and the deep peroneal nerve. The document also discusses common sites of nerve entrapment, such as the tarsal tunnel and abductor canals.<br /><br />Detailed techniques for needle EMG examination of various foot muscles, including the first dorsal interosseus pedis, fourth dorsal interosseus pedis, flexor digiti minimi brevis, abductor digiti quinti pedis, abductor hallucis, and extensor digitorum brevis, are provided. These techniques involve precise needle electrode placement and confirmation of muscle activation through patient movements.<br /><br />The document also addresses the clinical significance of EMG abnormalities. It suggests that prominent spontaneous activities, like positive sharp waves and fibrillation potentials, may indicate denervation. Needle EMG is considered both more specific and sensitive than nerve conduction studies (NCS) for diagnosing foot entrapment neuropathies.<br /><br />Finally, the importance of a comprehensive examination that includes both affected and unaffected muscles, potentially extending to other limb and paraspinal muscles, is emphasized to create a complete clinical picture for accurate diagnosis and treatment.

Keywords

needle EMG

foot muscles

entrapment neuropathies

sciatic nerve

tibial nerve

deep peroneal nerve

electrodiagnostic consultants

nerve entrapment

clinical interpretation

denervation