Sheath introduction apparatus and method

A sheath system for enabling access through an opening in the body of a patient, the sheath system comprising:

• a dilation assembly having a radially expandable tubular sheath defining a lumen having a first cross-sectional area when in a non-expanded condition, and a handle assembly operatively coupled to a proximal end of the tubular sheath, the handle assembly defining an aperture formed therein, and a first thread defined on the handle assembly in the aperture thereof;
• and
• an expansion assembly including a tubular member defining a lumen having a second cross-sectional area which is larger than the first cross-sectional area of the tubular sheath of the dilation assembly, the tubular member having an outer surface defining a second thread formed along substantially an entire length of the tubular member from a location at least in close proximity to a distal end of the tubular member to a location in close proximity to a proximal end of the tubular member, the second thread being arranged for engaging the first thread to axially advance the tubular member along the entire length thereof through the tubular sheath.