| 摘要 |
A trocar is provided having a needle unit. The needle unit has a paracentetic section, which is substantially pyramidal. The paracentetic section has two curved surfaces that diagonally oppose each other. The surfaces are formed by cutting the ridges of the section, which diagonally oppose each other. The remaining two ridges of the paracentetic section make, respectively, sharp cutting edges for cutting living tissues. The cutting edges are substantially symmetrical to each other with respect to the axis of the needle unit.
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