Pivot joint in rotating an arm inward). When rotating the forearm, these movements are typically called pronation and supination. In the standard anatomical position, the forearms are supinated, which means that the palms are facing forward, and the thumbs are pointing away from the body. In contrast, a forearm in pronation would have the palm facing backward and the thumb would be closer to the body, pointing medially. Examples of a pivot joint include: In contrast, spherical joints (or ball and socket joints) such as the hip joint permit rotation and all other directional movement, while pivot joints only permit rotation. Pivot
Bicycle saddle forward and backward and to tilt up and down around the axis of the bolt. There are two common types of built-in saddle clamps for standard rails, both associated with genericized trademarks: I-beam rails are long and allow a wide fore-aft adjustment range. I-beam saddle clamps use two clamping bolts for grab pieces holding the single rail. Other historical saddle clamp variations included the Ideale saddle/Zeus post combination, which used a special seat post designed to forgo the need for a clamp in order maximize weight savings. A saddle may contain one or more suspension components to improve rider comfort