US Patent 7569054 Tubular member having a passage and opposed bone contacting extensions

An apparatus for use in human surgery has a tubular member with a passage for providing protected access to a surgical site. The passage has a minimum width transverse to the mid-longitudinal axis of the tubular member. Two opposed extensions extend from the distal end of the tubular member. The extensions each have a length and a maximum height perpendicular to the length. The maximum height of the extensions are less than the length of each extension and greater than one-half the minimum width of the passage. Each extension has an interior surface at least in part facing the mid-longitudinal axis of the tubular member. The interior surfaces of the extensions are spaced apart from one another along the length of each extension a distance no less than the minimum width of the passage. Each extension has opposed bone contacting surfaces configured to contact portions of bone.