Cracking your knuckles doesn’t cause arthritis, a common myth debunked by science. The popping sound comes from gas bubbles (mostly nitrogen) in the synovial fluid bursting in the joint capsule when you stretch the metacarpophalangeal joints—a process called tribonucleation. Studies, including long-term research on habitual knuckle crackers, show no link to osteoarthritis or rheumatoid arthritis, […]