Checkpoint: Clarifying Concepts in NCS: Upper and Lower-Session recording

Video Transcription

Video Summary

This comprehensive lecture by Dr. Daniel Cai and colleagues covers the detailed anatomy and electrodiagnostic testing of lower and upper limb peripheral nerves, emphasizing practical clinical applications. For the lower limb, Dr. Cai reviews the common peroneal nerve—the most frequent cause of foot drop—and its vulnerability as it winds superficially around the fibular head, with risk factors like leg crossing and rapid weight loss highlighted. The bifurcation into deep and superficial branches and their motor/sensory innervations are explained alongside nerve conduction study (NCS) techniques that assess these regions. The tibial nerve’s course and its common entrapment at the tarsal tunnel are discussed, including testing of medial and lateral plantar branches and the sural nerve’s sensory role. Proximal nerves like sciatic and femoral are outlined, with femoral impacting hip flexion and knee extension, including nerve conduction set-ups for femoral neuropathies.<br /><br />Upper limb coverage explores the brachial plexus-derived nerves: axillary nerve’s vulnerability near the surgical neck of the humerus, radial nerve’s multiple entrapment sites (including the spiral groove and supinator arcade), musculocutaneous nerve’s rare neuropathies and importance in plexopathy testing, median nerve’s entrapments including carpal tunnel and pronator teres syndrome, and ulnar nerve’s common entrapment at the elbow and less commonly the Guyon’s canal. The講ers detail motor and sensory nerve conduction studies for each nerve, emphasizing anatomical variations such as the Martin-Gruber and Marinacci anastomoses affecting interpretations.<br /><br />The session closes with a practical demonstration focusing on recording techniques, stimulation sites, pitfalls like co-stimulation or anomalous innervations, and strategies to improve NCS accuracy, particularly in challenging proximal nerve studies. The importance of side-to-side comparisons and integrating ultrasound for anatomical localization is also emphasized. The presentation offers valuable insights for electrodiagnostic clinicians to enhance diagnostic accuracy and understanding of common neuropathies in clinical practice.

Keywords

peripheral nerve anatomy

nerve conduction studies

ncs

common peroneal nerve

foot drop

tibial nerve entrapment

brachial plexus

radial nerve neuropathy

median nerve entrapment

ulnar nerve compression

electrodiagnostic testing

nerve conduction techniques

ultrasound localization