| 摘要 |
<p>An expandable cannula (15) having a plurality of wall surfaces (20)-(23), (30)-(33), (40)-(43), (50)-(53), the wall surfaces being foldable together one over another such that the cannula assumes a first cross-sectional area, and the wall surfaces being un-foldable such that the cannula assumes a second cross-sectional area, wherein the first cross-sectional area is smaller than the second cross-sectional area.</p> |
