Abstract: Medical devices and methods for accessing a biological body are disclosed herein. In one embodiment, a method includes inserting a cannula at least partially into a vertebra such that a threaded portion of the cannula secures the cannula to a portion of a cortical bone of the vertebra and forms a channel within the cortical bone. A medical device is inserted at least partially through the cannula such that a distal end portion of the medical device is disposed within a portion of a cancellous bone of the vertebra. A medical procedure is performed within the cancellous bone using the medical device and then the cannula and the medical device are removed from the vertebra, leaving a channel in the vertebra having at least partially threaded interior walls. A bone screw that has threads configured to matingly engage the threaded channel is then inserted into the threaded channel.

Abstract: In one embodiment, an apparatus includes a projection having a tapered end portion configured to be inserted percutaneously through tissue. A measurement member is coupled to the projection and is configured to indicate a distance between adjacent anatomical structures. In another embodiment, an apparatus includes a measurement member configured to be percutaneously inserted between adjacent anatomical structures. The measurement member includes a wedge portion that is configured to contact the adjacent anatomical structures when the measurement member is moved distally between the adjacent anatomical structures. A size indicator is coupled to the wedge portion. The size indicator has a plurality of markings and is configured to be viewed on an image of the adjacent anatomical structures with the wedge portion of the measurement member disposed between the adjacent anatomical structures to indicate a distance between the adjacent anatomical structures.