Pivot joint Pivot joint In animal anatomy, a pivot joint (trochoid joint, rotary joint, lateral ginglymus) is a type of synovial joint. In pivot joints, the axis of a convex articular surface is parallel with the longitudinal axis of the bone. According to one classification system, a pivot joint like the other synovial joint —the hinge joint has one degree of freedom. Note that the degrees of freedom of a joint is not the same as the same as joint's range of motion. Pivot joints allow for rotation, which can be external (for example when rotating an arm outward), or internal (as
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