Skip to main content Accessibility help
×
Hostname: page-component-5d59c44645-kw98b Total loading time: 0 Render date: 2024-02-28T10:56:21.359Z Has data issue: false hasContentIssue false

Chapter 10 - Electromyography (EMG)

Published online by Cambridge University Press:  14 September 2023

John A. Jarratt
Affiliation:
Emeritus, Sheffield Teaching Hospitals NHS Foundation Trust
Get access

Summary

Electromyography is used to differentiate primary muscle disease (myopathy) from abnormalities within the muscle resulting from pathology of its nerve supply (neuropathy). The diagnosis rests on the assessment of motor unit size and an estimate of motor unit numbers during voluntary activity, the recruitment pattern. That motor unit size is reflected in motor unit potential duration is explained and illustrated. Excessive polyphasic motor unit potentials are abnormal but do not, by themselves, distinguish between neuropathy and myopathy. The limitations of assessing motor unit numbers are acknowledged. Potentials may also be recorded from resting muscles. These may be normal as in end-plate potentials or end-plate noise, or abnormal as in fibrillation potentials, positive sharp waves, fasciculation potentials, myotonia, myokymia or complex repetitive discharges. Elegant examples of all of these are included.

Type
Chapter
Information
Publisher: Cambridge University Press
Print publication year: 2023

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

  • Electromyography (EMG)
  • John A. Jarratt, Emeritus, Sheffield Teaching Hospitals NHS Foundation Trust
  • Book: Essential Electromyography
  • Online publication: 14 September 2023
  • Chapter DOI: https://doi.org/10.1017/9781009381055.011
Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

  • Electromyography (EMG)
  • John A. Jarratt, Emeritus, Sheffield Teaching Hospitals NHS Foundation Trust
  • Book: Essential Electromyography
  • Online publication: 14 September 2023
  • Chapter DOI: https://doi.org/10.1017/9781009381055.011
Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

  • Electromyography (EMG)
  • John A. Jarratt, Emeritus, Sheffield Teaching Hospitals NHS Foundation Trust
  • Book: Essential Electromyography
  • Online publication: 14 September 2023
  • Chapter DOI: https://doi.org/10.1017/9781009381055.011
Available formats
×