A medical tool includes an access tool and a dissecting obdurator that is placed within a lumen of the access tool. The dissecting obdurator comprises a body having a first edge, a second edge and a cross section, the cross section having a height dimension measured from the first edge to the second edge and a width dimension perpendicular to the height dimension, the height dimension is two or more times the width dimension. The tip of the dissecting obdurator is selectively flexible and coupled to a distal end of the body, the selectively flexible tip being more flexible bending in the axis of the width dimension than bending in the axis of the height dimension.
