A sheath for deploying a medical device to a target site in the body of a patient. A tubular inner liner has a proximal portion, a distal portion, and an outer surface. An outer jacket has a proximal portion, a distal portion, and an inner surface. A reinforcing member is received within a length of the outer jacket. The outer jacket is positioned longitudinally around the inner liner and bonded to the outer surface of the liner. The reinforcing member, which may be a triaxial braid, or an encapsulated longitudinal reinforcing wire, extends along the outer jacket length and is configured for inhibiting elongation of the sheath upon deployment of the device.