This invention relates to an articulating component (16) of a downhole assembly, and to a downhole steering assembly. There is provided an articulating component (16) having a first end (40) and a second end (42), the articulating component being adapted to transmit torque between the first end and the second end. The articulating component has a pivotable coupling (46) between its first and second ends and at least one control element for the pivotable coupling, the control element(s) having an active condition in which the pivotable coupling is substantially locked against pivoting movement, and an inactive condition in which the pivotable coupling is unlocked. In a downhole steering assembly the articulating component is located downhole of the steering component whereby to protect the steering component from unwanted vibrations generated downhole, or uphole of the steering component whereby to protect the steering component from unwanted vibrations generated uphole, or both.