| 摘要 |
A trocar for placement in the lumen of a cannula to facilitate insertion of the cannula through the wall of a body cavity is described. The trocar comprises a handle, an obturator having a proximal portion and a distal portion with a cutting surface for piercing the wall of the body cavity, and an axis. The proximal and distal portions of the obturator are mounted for relative angular movement about the axis of the obturator. A mechanism retracts the obturator proximally relative to the cannula along an axial path as the proximal and distal portions move angularly relative to each other after the cutting surface has at least partially penetrated through the wall of the body cavity. Preferably, the path is free of distal movement of the obturator relative to the cannula.
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