What happens when you crack your neck?
When you crack your neck, the cracking noise originates from synovial fluid inside the joint.
When you crack your neck, or a different joint, the joint capsule stretches.
When the joint stretches, the fluid inside the joint, called synovial fluid, releases a bubble of air.
When the bubble pops and an audible crack is produced.
But cracking your neck to relieve pain and pressure is only a temporary fix and can lead to problems down the road.