The present invention is directed to medical catheters that may be modularly constructed to facilitate manufacture and provide properties that may be difficult to achieve with a catheter formed from a single extrusion or multiple materials that are fused together. The catheter may be constructed of one or more core elements that may be partially or fully surrounded by a jacket member in a variety of configurations. The core elements may comprise different properties with respect to the jacket member or one another, thereby permitting increased manufacturing flexibility. The modular catheter designs of the present invention further provide for a variety of lumen configurations, as well as providing for catheters that can change their shape by moving the core elements with respect to the jacket member or one another.
