| 摘要 |
PROBLEM TO BE SOLVED: To provide a trocar cannula capable of keeping air-tightness in the interior of the cannula regardless of the size of a medical instrument inserted in the inside of the cannula and its arrangement condition. SOLUTION: This trocar cannula 1 used together with an inner needle has an insert part 3 having a conduit 2 inside, a holding part 4 provided on the base end side of the insert part 3, and a seal member 6 as a sealing means for keeping the air-tightness of a chamber 5 in the holding part 4. The seal member 6 formed of an elastic material has an instrument insert part 21 provided with an insert part opening 20 as an opening through which a medical instrument is passed, and a seal ring 22 as an opening reducing means for energizing the bore diameter of the opening 20 to be reduced is fitted to the outer periphery thereof. When the medical instrument is inserted in the opening 20, the seal ring 22 fastens the insert part 21 toward the radial inside regardless of the size of the outside diameter and the arrangement condition, whereby the opening edge 20a is made closely adhere to the outer periphery of the medical instrument to keep the air-tightness in the holding part 4.
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