In anatomy, a bony projection or process; specifically, the outward protrusion or eminence on a bone.
From Latin exire (to go out, to project) combined with the noun suffix -ion. The term refers to something that literally sticks out or projects from a bone surface.
Your skeleton is full of exions—they're the bumps and ridges on bones where muscles attach. If you feel the back of your head, that hard knob is an exion where your neck muscles anchor, giving them leverage to move your head!
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