After the Civil War , with the protection of the Thirteenth , Fourteenth , and Fifteenth Amendments to the Constitution and the Civil Rights Act of 1866 , African Americans enjoyed a period when they were allowed to vote , actively participate in the political process , acquire the land of former owners , seek their own employment , and use public ...
In the knee, for example, cracking or popping may occur if the patella (knee cap) is slightly out of alignment, and rubs on the adjacent tissues. Other causes of joint noise are the snapping of tendons or scar tissue over a prominence or something referred to as cavitation. Cavitation frequently occurs in synovial joints when a small vacuum forms in the synovial fluid and a rapid release produces a sharp popping or cracking sound.
Cracking your knuckles may aggravate the people around you, but it probably won't raise your risk for arthritis. That's the conclusion of several studies that compared rates of hand arthritis among habitual knuckle-crackers and people who didn't crack their knuckles. The pop of a cracked knuckle is caused by bubbles bursting in the synovial fluid â the fluid that helps lubricate joints. The bubbles pop when you pull the bones apart, either by stretching the fingers or bending them backward, creating negative pressure.