World Library  
Flag as Inappropriate
Email this Article

Extension (kinesiology)

Article Id: WHEBN0008981589
Reproduction Date:

Title: Extension (kinesiology)  
Author: World Heritage Encyclopedia
Language: English
Subject: Whiplash (medicine), Plantar reflex, Plyometrics, Interspinales muscles, Asterixis, Abnormal posturing, Vastus medialis, Extensor digitorum muscle, Extensor pollicis longus muscle, Abductor pollicis longus muscle
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Extension (kinesiology)

This article is about the movement of anatomical joints. For the body exercise, see Hyperextension (exercise).


In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed (bent) elbow. Straightening of the arm would require extension at the elbow joint. If the head is tilted all the way back, the neck is said to be extended.

In some anatomical muscle names, particularly with muscles of the forearm and the Cnemis, the term occurs explicitly as the second word in the Latin spelling of the name (for example, Musculus extensor carpi ulnaris).

While extension is a movement, the terms "extend" versus "flexed" refer to the final position of a body part with reference to the anatomical position of the body. For example, if an arm fully bent at the elbow is slightly extended, it will still be called "flexed" or "semiflexed", and will be called "extended" only upon complete straightening of the arm.

The movement in the opposite directions is called flexion. Flexion decreases the angle between the bones of the limb at a joint, while extension increases it.

With the foot, extension is usually called plantarflexion.

Hyperextension

If a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion, then one speaks of a hyperextension (as with the knee). This puts a lot of stress on the ligaments of the joint, and need not always be a voluntary movement, but may occur as part of accidents, falls, or other causes of trauma.

Hyperextension is also sometimes defined as normal movement into the space posterior to the anatomical position.[1]

Muscles of extension

Upper limb

Lower limb

Back

References

External links

  • eMedicine Dictionary
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.