Articulable tube assemblies

A steerable instrument comprising:

• an elongate member having a proximal portion, a distal portion, an actuation region at the proximal portion, and an articulable region at the distal portion, and:
• a first elongate tube comprising a sidewall and having a tendon formed of the sidewall, the tendon extending between a proximal end portion at the actuation region and a distal end portion at the articulable region, wherein the tendon is configured to transfer a force applied at the actuation region to the articulable region to cause articulation of the articulable region, and
• a second elongate tube coaxial with the first elongate tube and comprising a sidewall, wherein at least a portion of the sidewall axially coincides with the articulable region and comprises a plurality of bridge regions and a plurality of struts regions alternating with the plurality of bridge regions along a circumference of the second elongate tube such that the strut regions extend circumferentially between and connect the bridge regions, and wherein:
• each of the plurality of bridge regions comprise a plurality of bridges axially spaced apart from one another,
• each of the plurality of strut regions comprise a plurality of struts, each of the struts extending between bridges of circumferentially adjacent bridge regions, and
• at least when the at least a portion of the sidewall is in a straight configuration, each of the struts extend at a non-perpendicular angle relative to a longitudinal axis of the second elongate tube.

An instrument comprising:

• an elongate member formed of a tubular sidewall, wherein at least a portion of the tubular sidewall comprises a plurality of bridge regions and a plurality of struts regions alternating with the plurality of bridge regions along a circumference of the elongate member such that the strut regions extend circumferentially between and connect the bridge regions, and wherein:
• each of the plurality of bridge regions comprise a plurality of bridges axially spaced apart from one another,
• each of the plurality of strut regions comprise a plurality of struts, each of the struts extending between bridges of circumferentially adjacent bridge regions, and
• at least when the elongate member is in a straight configuration, within a given strut region, each of the struts extend at an angle relative to an axially adjacent strut.