Sheath for maintaining position in a body cavity

A sheath for implanting a medical device or medical equipment into a body cavity of a patient, said sheath comprising:

• a sheath wall comprising at least one anchoring element disposed at a distal portion of the sheath, said anchoring element comprising a distal tip and a proximal tip,
• wherein said anchoring element is in the form of a hinge or hook,
• wherein said sheath wall is pre-formed to cause the proximal tip of the hinge or hook to extend from a generally cylindrical surface of the sheath wall when not forced to remain substantially in the same shape as the remaining portion of the sheath wall by pressure exerted on the distal tip of the hinge or hook by a structure disposed within the lumen of the sheath, and
• wherein extension of the proximal tip of the hinge or hook away from the generally cylindrical surface of the sheath wall extends the distal tip of the hinge or hook into the lumen of the sheath, and creates an anchor that retains the distal tip of the sheath within the body cavity by contact of proximal tip of the anchor with a body cavity surface,
• wherein contact of the distal tip of the hinge or hook with an outer surface of a mechanical element of sufficient diameter into the lumen of the sheath causes retraction of the hinge or hook, thus disabling the anchoring function and allowing removal of the sheath without tearing of the body cavity surface.