2025 Workshop Handout Bundle-W83RTA Basic Nerve US Upper limb

W83RTA Basic Nerve US Upper limb - Sultan

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This document by Dr. Shumaila Sultan provides an overview of the use of ultrasound (US) in evaluating nerves and muscles of the upper limb, especially in common entrapment neuropathies. It begins with a historical perspective, highlighting key milestones such as the discovery of the piezoelectric effect by Pierre and Jacques Curie, early ultrasound applications in medical diagnosis by Karl Dussik, and later developments in obstetric ultrasound and B-mode imaging.<br /><br />Ultrasound basics are covered, including imaging conventions and sound frequency categories ranging from infrasound to diagnostic ultrasound (around 1 MHz). The adoption of neuromuscular ultrasound in electrodiagnostic medicine started in the late 1980s and early 1990s, with Dr. Fornage and Dr. Buchberger pioneering peripheral nerve imaging and diagnosing carpal tunnel syndrome (CTS).<br /><br />The document details ultrasonographic features useful in entrapment neuropathies, emphasizing nerve cross-sectional area (CSA) enlargement criteria—either 2 standard deviations above normal or 1.5 times enlargement compared to unaffected nerve segments. Specific entrapments discussed include:<br />- Median nerve at the wrist (CTS): CSA cutoff ~10-12 mm², with high sensitivity and specificity; more prevalent in women.<br />- Ulnar neuropathy at the elbow: CSA upper normal limit around 9-10 mm², more common in men.<br />- Ulnar neuropathy at the wrist: CSA upper limit 8 mm², often due to anatomical abnormalities.<br />- Fibular neuropathy at the knee: most common lower limb entrapment, CSA up to 20 mm², with frequent intraneural ganglion cysts treatable by surgery.<br /><br />Muscle ultrasound assessments focus on echogenicity (graded by Heckmatt Score I-IV), size measurements, fascia appearance, and abnormal movements like fasciculations. Normal muscle appears hypoechoic with speckled "starry night" texture, while diseased muscles become hyperechoic due to fat and fibrosis accumulation. Proper measurement techniques depend on standardized probe placement and patient positioning.<br /><br />Overall, neuromuscular ultrasound is a valuable, non-invasive tool for diagnosing and monitoring peripheral nerve disorders and muscle pathology, aiding in clinical decision-making and guiding biopsies.<br /><br />Key references include works by Cartwright et al. on neuromuscular ultrasound diagnostics and studies on ultrasound applications in entrapment neuropathies.

Keywords

ultrasound

nmus

sono

neuromuscular ultrasound

entrapment neuropathies

nerve cross-sectional area

carpal tunnel syndrome

CTS

ulnar neuropathy

fibular neuropathy

muscle echogenicity

Heckmatt Score

peripheral nerve imaging