Cracking your knuckles can accomplish so many things: release tension in your fingers, keep your hands busy, totally annoy those around you and possibly even freak them out - all valid reasons. Just how do you do it, though? To crack your knuckles, interlock your hands, then quickly straighten your fingers and push slightly into each knuckle until you hear a crack.
It's Metafilter's 20th anniversary! To celebrate, scan some cats or help fund Mefi! Why do my thumb knuckles always crack?
Rest assured that the most common causes of finger-popping are not a problem at all. Many people can make their fingers pop, often called cracking their knuckles. The sound you hear is thought to be caused by air bubbles moving in the fluid that surrounds your joints. That being said, if your noisy finger joints are associated with pain or swelling, it's good to see your doctor for an evaluation.
First things first: if your thumb joint is swollen, hot, and inflamed you should seek medical care immediatelyas this could be a sign of a severe infection. In a normally functioning hand, tendons run through sheaths or pulleys to the fingers to make them bend. With trigger thumb, medically known as stenosing tenosynovitisthe tendon sheaths a tunnel-like structure that holds the tendon to the bone become inflamed and thickened, making it difficult for the tendon to smoothly glide through the sheath to bend the affected finger.
The most common cause of a broken knuckle is punching a hard surface, such as a wall or a door. Other common causes include fights, contact sports, and accidental falls. Broken knuckles, also known as metacarpal fractures, are common.
Knuckle cracking is a common behavior enjoyed by many. Despite how common it is, there has been considerable debate regarding where the noise comes from. Fortunately — at least for those of us who are curious about it — knuckle cracking has been the subject of a fair amount of research.
Elementary school? I even force my boyfriend to crack my back for me sometimes—a textbook case of codependence. Actually, the process has to do with your joints. When you pull or bend your fingers the two most common cracking motionsyou stretch that fluid-filled capsule.
To understand what happens when you "crack" your knuckles, or any other joint, first you need a little background about the nature of the joints of the body. The type of joints that you can most easily "pop" or "crack" are the diarthrodial joints. These are your most typical joints.
Cracking joints is bending one's joints to produce a distinct cracking or popping sound. It is sometimes performed by physical therapistschiropractorsosteopathsand masseurs in Turkish baths. The cracking of joints, especially knuckles, was long believed to lead to arthritis   and other joint problems. However, medical research has not demonstrated such a connection.