Overview
This lecture explains the science behind why knuckles crack and clarifies common misconceptions.
Knuckle Cracking Myths
- Many people believe knuckles crack because bones are breaking or rubbing together.
- In reality, no bone is being damaged or cracked during the process.
The Science Behind the Sound
- Joints are lubricated with a fluid called synovial fluid.
- Synovial fluid contains dissolved gases.
- Stretching or bending fingers pulls the joint apart and creates negative pressure.
- The negative pressure causes gases in the fluid to form bubbles quickly.
- The signature cracking sound comes from these bubbles popping or dissolving.
Key Terms & Definitions
- Synovial Fluid â Lubricating fluid present in joints that contains dissolved gases.
- Negative Pressure â A decrease in pressure that creates a vacuum effect within the joint.
- Bubble Formation â The rapid creation of gas bubbles in synovial fluid due to negative pressure.
Action Items / Next Steps
- Review the explanation of synovial fluid and its role in joint movement.