"Rear knuckles" refers to the joints in the back part of a person's or animal's body, specifically the joints connecting the long bones of the upper leg to the lower leg. Full definition
Those new rear knuckles are less susceptible to flexing in hard driving, which means the rear contact patch is more stable, improving mechanical grip. (evo.co.uk)
New aluminum rear knuckles help reduce unsprung mass for improved ride and handling. (topspeed.com)
If bolt 56280 - JA000 needs to be replaced at the rear shock absorber to rear knuckle location, and the vehicle is a 2002 - 2012 Altima or 2004 - 2012 Maxima, order bolt 56280 - JA00A instead of 56280 - JA000. (autoserviceprofessional.com)