Articulatable members having constrained motion and related devices and methods

An articulatable member, comprising:

• a plurality of links extending in a series from a proximal end link to a distal end link, adjacent links of the plurality of links being pivotably coupled to form joints between adjacent links;
• an actuation member extending from the proximal end link to the distal end link,
• wherein the actuation member is operably coupled to the plurality of links to transmit force to bend the articulatable member from a neutral position;
• and
• a constraint member extending from the proximal end link to the distal end link,
• wherein the constraint member has opposite ends that are fixed to the distal end link and the proximal end link, respectively,
• wherein the constraint member extends through a throughhole in each link of the plurality of links, the throughhole being radially offset from a central axis of the link, and
• wherein the constraint member follows a helical path along at least a portion of the articulatable member from the proximal end link to the distal end link;
• wherein, in a straight configuration of the articulatable member, the constraint member is under tensile force between the opposite ends.