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Skeletal System

What are the joints of carpal bones?


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The joints between the carpal and metacarpal bones of the four fingers are arthrodial joints. The thumb is a saddle joint (trapeziometacarpal). The joints between the metacarpals and phalanges are condyloid joints (metacarpophalangeal), and the joints that are between two carpal bones (carpal to carpal) are gliding joints (intercarpals). Your thumb is a saddle joint and if you picture it like you are literally sitting in a saddle, imagine the direction you could move -- its the same concept. The base of your thumb (your butt in the saddle) cannot really move much, but you could lean back, side to side, forward and backward. It is named a saddle joint because its shaped like a saddle. A condyloid joint is an oval shaped, biaxial joint, meaning they can move in two directions. If you look at your palm of your hand and flex your index finger back and forth as if you are saying "come here" to someone, and then move the finger from side to side (toward the thumb), you can see the biaxial motion of the joint. Finally, the gliding joint. These joints are flat and allow for the bones to simply "slide" past one another, they do not bend. If you want to feel one in motion, put your fingers on your sternoclavicular joint, which is at the beginning of your clavicle, also known as your collar bone, where it connects with your sternum, or breast bone in the middle of your chest. Here you will find two bumps, these are the sternoclavicular joints. Put your fingers on one of them with the opposite hand, and then raise your arm over your head. You should feel it move. This is what makes it a gliding joint, it only moves slightly.