The instrument has a flexible wrist (40) that includes a flexible tube (42) and an inner spring (47). The inner spring is disposed inside the interior cavity of the flexible tube, and has an axis parallel to the axis of the flexible tube. Actuation cables (44) are used for bending the wrist in pitch rotation and yaw rotation. The actuation cables have distal portions connected to an end effector, and extend from the distal portion through the wrist towards an elongated shaft to the proximal portion. The proximal portion of the wrist is connected to the working end of the elongated shaft. The distal portion of the wrist is connected to the end effector.
