Surgical drapes reliably maintain sterility in the operating room and enable easy and efficient installation on and removal from a surgical instrument such as a surgical instrument at the end of a robotic surgical arm. The surgical drape comprises a transitional sheath such that in a deployed configuration a second end of the sheath is spaced relatively away from a first end of the sheath and in an un deployed configuration the second end of the sheath is spaced relatively close to the first end of the sheath. The sheath may further include a stiffening member secured to the second end a pull member coupled to the stiffening member and at least one access port formed in the first end of the sheath such that each access port is adapted for the passage of surgical instruments therethrough.
