An articulatable access system for accessing a body cavity comprising: a shaft having a proximal end, a distal end, and a central lumen therethrough, wherein a portion of the shaft comprises a series of articulating members, wherein the distal end is passable through to the body cavity and wherein the central lumen is sized for passage of an interventional device therethrough; a first set of pullwires fixedly attached to the shaft at a primary attachment point such that applying tension to the first set of pullwires deflects the articulating members to form a primary curve, the primary curve having a first radius; a second set of pullwires fixedly attached to the shaft at a secondary attachment point such that applying tension to the second set of pullwires deflects the articulating members to form a secondary curve, the secondary curve having a secondary radius different than the first radius; a third set of pullwires fixedly attached to the shaft at a distal attachment point such that applying tension to the third set of pullwires moves the distal end of the shaft through an angle theta, wherein the pullwires (120,124,128) extend through one or more pullwire lumens in the walls of the articulating members, at least some of the pullwire lumens being oblong and adapted to reduce binding of the pullwire (120,124,128) passing therethrough, the oblong pullwire lumens having a length in the circumferential direction longer than a width in the radial direction; the system further comprising: an obturator removably positionable in the central lumen and configured to position the portion of the shaft in a first shape; and a locking mechanism to hold the articulating members in a fixed articulated position to direct the device to the body cavity; wherein each of the articulating members is independently rotatable against an adjacent articulating member; and wherein the locking mechanism comprises a friction surface on at least a portion of the articulating members to enhance friction between the articulating members. a shaft having a proximal end, a distal end, and a central lumen therethrough, wherein a portion of the shaft comprises a series of articulating members, wherein the distal end is passable through to the body cavity and wherein the central lumen is sized for passage of an interventional device therethrough; a first set of pullwires fixedly attached to the shaft at a primary attachment point such that applying tension to the first set of pullwires deflects the articulating members to form a primary curve, the primary curve having a first radius; a second set of pullwires fixedly attached to the shaft at a secondary attachment point such that applying tension to the second set of pullwires deflects the articulating members to form a secondary curve, the secondary curve having a secondary radius different than the first radius; a third set of pullwires fixedly attached to the shaft at a distal attachment point such that applying tension to the third set of pullwires moves the distal end of the shaft through an angle theta, wherein the pullwires (120,124,128) extend through one or more pullwire lumens in the walls of the articulating members, at least some of the pullwire lumens being oblong and adapted to reduce binding of the pullwire (120,124,128) passing therethrough, the oblong pullwire lumens having a length in the circumferential direction longer than a width in the radial direction; the system further comprising: an obturator removably positionable in the central lumen and configured to position the portion of the shaft in a first shape; and a locking mechanism to hold the articulating members in a fixed articulated position to direct the device to the body cavity; an obturator removably positionable in the central lumen and configured to position the portion of the shaft in a first shape; and a locking mechanism to hold the articulating members in a fixed articulated position to direct the device to the body cavity; wherein each of the articulating members is independently rotatable against an adjacent articulating member; and wherein the locking mechanism comprises a friction surface on at least a portion of the articulating members to enhance friction between the articulating members.