A sheath with improved kink resistance and/or rupture resistance is provided. The sheath includes an inner liner defining a passageway extending longitudinally therethrough. A coil is fitted around at least a part of the inner liner. An outer layer adapted to adhere to the inner liner between the windings of the coil is positioned longitudinally over the coil. Lateral edges can have inwardly curved and outwardly curved portions. Lateral edges can be further structured and arranged to define an asymmetric spacing therebetween. The asymmetric spacing is configured to improve at least one of kink resistance and rupture resistance of the sheath when in a bent configuration. The compressive and tensile strength of the polymer material can be utilized in a manner to inhibit coil segments from sliding along each other or overlapping one another, thereby preventing premature tearing of the material when the sheath is bent.
