A composite catheter is formed by the combination of a catheter body and a tubular member insertable or secured inside the catheter body. The tubular member contains a series of relatively rigid segments alternating with flexible, collapsible segments which permit the rigid segments to effectively stack...http://www.google.com/patents/US5632734?utm_source=gb-gplus-sharePatent US5632734 - Catheter shape control by collapsible inner tubular member
