the extension of a part of the body beyond normal limits.
Origin of hyperextension
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
extension of an arm or leg beyond its normal limits
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Extension of a joint beyond its normal range of motion.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.