An introducer sheath has a tubular structure that is expandable and contractible to a desired diameter. In a first configuration, the tubular structure has a first diameter and a first axial length. In a second configuration, the tubular structure has a larger second diameter and a shorter second axial length. An actuator includes an inner member and an outer member. In response to relative movement between the members and the tubular structure in a first or second direction, the actuator allows the tubular structure to move to the respective between the first or second configurations. The tubular structure can be a braided structure. The members can form an everted tubular sleeve. A proximal end of the outer sleeve is movable relative a proximal end of the inner sleeve. A locking system can fix the introducer sheath at a desired diameter.
