An actuatable joint is disclosed having a transmission member, for example a ring gear, associated with a member of a joint and rotatable about a longitudinal axis through the member. In particular a two degree of freedom actuatable joint is disclosed comprising tendon driven joint arrangements having a transmission member disposed around or inside a body of the joint arrangement, to provide transmission of a force from a driving means to two tendons actuating a rotational degree of freedom of the joint arrangement. Further disclosed is a segmented device, for example an endoscope, comprising a plurality of such joints, for example to define a flexible and steerable conduit for an instrument.