Abstract: One aspect of the invention provides a sheath including: a cylinder defining a central passage; a balloon located along an external surface of a distal end of the cylinder, the balloon lying substantially flush with or recessed from the external surface when deflated, but capable of projecting beyond the external surface when inflated; and an inflation port located at a proximal end of the cylinder, the inflation port in fluid communication with the balloon. Another aspect of the invention provides a kit including: a sheath as described herein and instructions for use.