The longer of the two forearm bones, located on the medial (pinky finger) side of the forearm. It forms the primary articulation with the humerus at the elbow and provides stability during forearm rotation alongside the radius.
From Latin 'ulna' meaning elbow or forearm, originally a unit of measurement based on the length from elbow to fingertip. This reflects the bone's prominence in defining forearm length and elbow structure.
Your ulna is like the stable post of your forearm - while the radius rotates around it to turn your palm up and down, the ulna stays relatively fixed and forms the main hinge joint at your elbow! The olecranon process (the bony point of your elbow) is actually part of the ulna, which is why elbow fractures often involve this bone.
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