Patent ID: 8047236

Claim:
A flexible conduit for insertion into a body lumen, comprising: a plurality of elements coupled end to end with lumens of the elements aligned to define a conduit lumen, the plurality of elements including: a first element including a male portion and a female portion; a second element including a female portion having an inner surface extending along a curve corresponding to a curve of the male portion of an outer surface of the first element so that, when the male portion of the first element is received within the female portion of the second element, the first and second elements form a first ball joint; a third element including a male portion, an outer surface of the male portion of the third element being curved along a shape corresponding to a curve of an inner surface of the female portion of the first element so that, when the male portion of the third element is received within the female portion of the first element, the first and third elements form a second ball and socket joint, the male and female portions of the first element being adapted to frictionally engage respectively, the female portion of the second element and the male portion of the third element to establish a rigidity of the conduit sufficient to retain its shape and absorb forces applied thereto as a flexible instrument is inserted through the conduit lumen; and a force applying mechanism received within the conduit lumen and being movable between a first retracted configuration and a second expanded configuration applying a force radially outward against the male portion of the first element to increase a frictional engagement between the male portion of the first element and the female portion of the second element and increase a stiffness of the flexible conduit.