JP5557678B2 - Endoscope - Google Patents

Description

  The present invention relates to an endoscope.

  As an endoscope used for diagnosis of particularly thin parts such as the bile duct and pancreatic duct near the duodenum, an objective lens of the imaging system and an opening leading to the treatment instrument insertion tube are provided on the side surface of the distal end portion of the endoscope insertion portion. A provided side-view type endoscope is used. For example, when diagnosing the inside of the bile duct opening to the duodenum, a catheter is inserted into the treatment instrument insertion tube, a contrast medium is injected into the bile duct by the catheter, and fluoroscopy is performed. Alternatively, a child endoscope (fiber scope) is inserted into a bile duct through a treatment instrument insertion tube and observation is performed (Patent Document 1). In this case, since the inside of the treatment instrument insertion tube is occupied by the child endoscope, forceps or the like cannot be inserted into the treatment instrument insertion tube. In other words, in a narrow area such as the inside of the bile duct, only observation was possible and treatment was not possible.

  Here, in order to enable observation and treatment at the same time, it is conceivable to use a direct-viewing endoscope in which an objective lens is provided forward in the insertion direction at the distal end of the insertion portion, and the insertion portion is inserted into the bile duct. However, in order to use in a narrow space, the bending performance of the insertion part is important. In particular, the treatment instrument insertion tube included in the insertion portion is generally larger in diameter and higher in rigidity than other members included in the insertion portion, and therefore the bending performance of the treatment instrument insertion tube is important. It becomes. In Patent Document 2, the treatment instrument insertion tube is made flexible by engraving a plurality of grooves on the side surface of the treatment instrument insertion tube over the entire circumference.

JP 2003-144381 A Japanese Patent Laid-Open No. 7-184834

  In recent years, when using an endoscope having a small-diameter insertion portion, there is a demand for bending the insertion portion with good operability. In particular, in order to insert the insertion part into the bile duct using a small-diameter and direct-view type endoscope and perform observation and treatment at the same time, while keeping the duodenal papilla in view in front of the duodenal papilla which is the entrance of the bile duct Since an operation of directing the distal end portion in the direction along the extending direction of the bile duct is required, the problem is that the insertion portion can be easily bent so as to cope with this fine operation.

  An object of the present invention is to provide an endoscope capable of improving the bending performance to the extent that it can cope with a narrow space in a body cavity.

An endoscope including an insertion portion that encloses a treatment instrument insertion tube,
The insertion portion has a bending portion bent in one direction by a bending operation,
In the bending section that is in a bending state in the treatment instrument insertion tube when the bending portion is bent, the flexibility of the inner peripheral side surface of the treatment instrument insertion tube that becomes the inner peripheral side during bending is much larger than the flexible peripheral side face of the outer peripheral side the treatment instrument insertion tube, and the higher the endoscope than the rigidity of the peripheral side face is the inner peripheral surface part.

  According to the endoscope of the present invention, the bending performance of the insertion portion can be improved to the extent that it can cope with a narrow space in a body cavity.

1 is an external view of an endoscope that is an example for describing an embodiment of the present invention. FIG. It is a front view of the front-end | tip part of an insertion part. It is a side view of a curved part. It is the IV-IV sectional view taken on the line of FIG. It is the schematic of the duodenum vicinity, and the figure which notched a part of duodenum. It is a figure which shows the state in which the front-end | tip part was inserted in the bile duct.

With reference to FIGS. 1-6, an example of the endoscope for demonstrating embodiment of this invention is demonstrated.
FIG. 1 is an external view showing an outline of a direct-view type endoscope 1. The endoscope 1 includes an operation unit 20 and an insertion unit 30 that is connected to the operation unit 20 at the proximal end side and is inserted into a body cavity (in particular, a bile duct). A universal cable 2 is connected to the operation unit 20, and the universal cable 2 is detachably connected to a control device (not shown) via a connector 3.

  The operation unit 20 includes an angle knob 21 that is operated for a bending operation, various operation buttons 23 relating to air / water supply, suction, imaging, and the like, and a treatment instrument insertion port 240 into which a treatment instrument such as forceps is inserted. Have One wire as a long member is connected to the angle knob 21 via a pulley (not shown). The wire is included in each of the operation unit 20 and the insertion unit 30, and the end of the wire is fixed inside the distal end portion 33 of the insertion unit 30.

  Each of the universal cable 2, the operation unit 20, and the insertion unit 30 includes various pipes, light guides, signal lines, and the like. Light emitted from the light source unit of the control device reaches the tip 33 through the light guide. Similarly, the air / water supply from the control device and the treatment instrument inserted from the treatment instrument insertion port 240 also reach the distal end portion 33 through the respective pipelines.

The insertion part 30 includes, in order from the operation part 20 side, a flexible part 31 having flexibility, and a bending part 32 that bends upward like a two-dot chain line in FIG. And a distal end portion 33 that changes the direction following the movement of the bending portion 32. The flexible portion 31 and the bending portion 32 are covered with an outer skin member 301 including a net, a rubber tube, and the like.
Note that the bending direction of the bending portion 32 is referred to as an upward direction assuming that the subject is mainly lying down. For example, when the bending portion 32 extends along the vertical direction, the X direction in the horizontal plane Alternatively, the Y direction is the vertical direction.

  FIG. 2 is a front view of the distal end portion 33. At the distal end portion 33, illumination light windows 331 and 332 guided by a light guide, an observation window 333 directed to the observation target portion, and a treatment instrument connected to the treatment instrument insertion port 240 (FIG. 1). An opening 334 that is an end of the insertion tube and a nozzle 335 attached to the air / water supply tube 27 (FIG. 4) are provided. An objective lens (not shown) is provided on the back side of the observation window 333. The optical axis of this objective lens is orthogonal to the paper surface of FIG. An imaging element such as a CCD or CMOS that photoelectrically converts an optical image formed through the objective lens is provided inside the distal end portion 33. This image sensor is connected to a signal processing unit of the control device via a signal line 28 (FIG. 4).

3 is a side view of the bending portion 32, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. In FIG. 3, illustration of an air / water supply tube, a light guide, a signal line, and the like is omitted.
The bending portion 32 has a plurality of node rings 321 that are rotatably connected to each other. The node ring 321 is formed in a substantially cylindrical shape with a circular cross section. A pair of connecting portions 321 </ b> A and 321 </ b> A are formed at both ends in the axial direction (Z-axis direction) of the node ring 321. These connecting portions 321A and 321A are formed on both sides of the node ring 321 in the diameter direction. The connecting portions 321A of the adjacent node rings 321 are connected to each other by the pin 320, so that the node rings 321 are connected to each other so as to be rotatable about the X-axis direction as a rotation center.

As shown in FIG. 4, a guide pipe 321 </ b> B through which the wire 211 is inserted is fixed to the inner peripheral portion on the Y axis direction upper side of the node ring 321. As described above, since the wire 211 is disposed only on a part of the circumference of the node ring 321, the direction of the bending operation is limited to one direction (here, the upward direction). Thus, by limiting the bending of the bending portion 32 by the bending operation in one direction and omitting the wire for bending in the other direction, the contents of the insertion portion 30 are reduced and the diameter is reduced.
Note that the number of wires related to the bending operation in one direction is not limited to one. For example, two or three wires related to the bending operation in one direction are provided at close positions on the circumference of the node ring 321. It may be done.

  When the wire 211 is pulled by the operation of the angle knob 21, the node rings 321 rotate relative to each other around the X axis (X rotation direction), and the rotation angles of the node rings 321 are integrated. Thus, the curved portion 32 as a whole bends upward as indicated by the two-dot chain line in FIG. The inner peripheral side in the curved shape at this time is referred to as a curved inner peripheral side, and the outer peripheral side is referred to as a curved outer peripheral side. A position having the smallest radius of curvature on the curved inner circumference side is referred to as an innermost circumference D. The wire 211 is provided closer to the inner side of the bending than the axis BB of the bending portion 32.

  A treatment instrument insertion tube 24 through which a treatment instrument is inserted is provided inside each node ring 321. As shown in FIG. 3, the treatment instrument insertion tube 24 is provided at a position eccentric from the axis BB of the bending portion 32 toward the curved outer peripheral side, that is, downward. The treatment instrument insertion tube 24 has a bending section C (FIG. 1) that is in a bending state when the bending portion 32 is bent. The curved section C is formed with a length corresponding to the arrangement length of the node rings 321. Here, the curved inner peripheral side surface portion of the treatment instrument insertion tube 24 is referred to as an inner peripheral side surface portion 24A, and the curved outer peripheral side surface portion of the treatment instrument insertion tube 24 is referred to as an outer peripheral side surface portion 24B.

  The inner peripheral side surface portion 24A in the curved section C is formed with a plurality of cut holes 241 that are opened at equal intervals in the longitudinal direction of the treatment instrument insertion tube 24, including a portion that is on the innermost peripheral D side during bending. Has been. By forming these cut holes 241, the flexibility of the inner peripheral side surface portion 24A is larger than the flexibility of the outer peripheral side surface portion 24B. The cut hole 241 is formed in a V shape in a side view, that is, the width of the gap is widest on the innermost circumference D side, and the width of the gap gradually narrows toward the radially inner side of the treatment instrument insertion tube 24. It is made into a shape. A portion on the curved outer peripheral side of the treatment instrument insertion tube 24 in the curved section C has a smooth continuous shape without a notch or the like.

In the inner peripheral portion of the treatment instrument insertion tube 24 in the curved section C, a sheet-like or film-like film-like member 242 that closes the plurality of cut holes 241 from the inside is provided. The film-like member 242 is formed of a material having airtightness and watertightness such as silicon rubber, latex rubber, PTFE, etc., and is adhered to the side surface of the treatment instrument insertion tube 24 in an airtight and watertight state. Yes. The membrane member 242 preferably has at least one of watertightness and airtightness, and is provided on the side surface portion of the treatment instrument insertion tube in a state where at least one of watertightness and airtightness inside the treatment instrument insertion tube is ensured. It is preferable to be provided.
Unlike the configuration described here, a film-like member may be provided on the outer peripheral portion of the side surface of the treatment instrument insertion tube 24.

  According to the above-described configuration, when the wire 211 is pulled by the operation of the angle knob 21, the treatment instrument insertion tube 24 is bent so that the vicinity of each cut hole 241 is close to each other, and each cut hole 241 is formed. In this part, no stress is exerted during bending. That is, since the flexibility of the inner peripheral side surface portion 24A is large because the cut hole 241 is formed, the resistance force when the treatment instrument insertion tube 24 is bent can be reduced. That is, the treatment instrument insertion tube 24 can be flexibly bent, and as a result, the bending portion 32 can be easily bent.

Here, the treatment instrument insertion tube 24 is required to be inserted into the treatment instrument, and even if it is in the insertion section 30 with a small diameter, the diameter is larger than the necessary diameter, and the proportion of the cross section of the insertion section 30 is high. Since it is formed with such a thickness that it will not be damaged when the treatment instrument is inserted, it is generally more rigid than other members. As described above, the flexibility of the treatment instrument insertion tube 24 having a relatively large diameter and high rigidity is imparted, so that the bending performance of the bending portion 32 is greatly improved.
Moreover, since the stress concentration at the time of bending of the treatment instrument insertion tube 24 is avoided by the plurality of cut holes 241, buckling of the treatment instrument insertion tube 24 can be prevented.

  FIG. 5 is a schematic view of the vicinity of the duodenum and a part of the duodenum cut out. The insertion portion 30 of the endoscope 1 is inserted from the oral cavity or nasal cavity and reaches the duodenum 11 that communicates with the stomach 10. At the time of this insertion, the angle knob 21 is operated as necessary to bend the bending portion 32. In the vicinity of the duodenum 11, a liver 12, a gallbladder 13, and the like are provided. A bile duct 14 is open on the side wall of the duodenum 11, and this open portion is a duodenal papilla 111 having a narrowed shape. The pancreatic duct 15 joins the bile duct 14.

  When the distal end portion 33 is inserted into the bile duct 14, the bending portion 32 is bent upward by operating the angle knob 21, and the distal end portion 33 is directed toward the duodenal papilla 111. Note that the path from the oral cavity or nasal cavity to the duodenum 11 is relatively simple, and when the distal end portion 33 is directed to the duodenal papilla 111, it is sufficient that the bending portion 32 can be bent upward. There is no problem even if the bending operation is limited to one direction. Here, since the treatment instrument insertion tube 24 is flexibly bent as described above, the bending portion 32 can be freely bent quickly and compactly even with a weak force. Therefore, the distal end portion 33 can be directed in the direction of looking up at the duodenal papilla 111 along the extending direction of the bile duct 14 while keeping the duodenal papilla 111 in the field of view before the duodenal papilla 111. 33 can be inserted easily.

FIG. 6 shows a state in which the distal end portion 33 is inserted into the bile duct 14 through the duodenal papilla 111. If necessary, the angle knob 21 is operated to change the bending angle of the bending portion 32, and the distal end portion 33 is moved inside the bile duct 14 to perform observation and treatment. When a treatment is performed, the treatment tool is supplied through the treatment tool insertion tube 24.
Here, since the inside of the treatment instrument insertion tube 24 is kept airtight and watertight by the membranous member 242, a suction operation using the treatment instrument insertion tube 24 as a suction path is possible. That is, it is possible to suck the liquid resulting from treatment or bleeding in the bile duct 14 through the treatment instrument insertion tube 24 without causing trouble such as liquid leakage from the cut hole 241.

  Further, when a treatment instrument such as forceps is inserted into the treatment instrument insertion tube 24, the treatment instrument passes through the curved outer peripheral portion where the cut hole 241 is not formed in the curved section C in the curved state. The distal end of the treatment instrument is caught on the edge of the cut hole 241 and the treatment instrument insertion tube 24 is hardly pulled out. In addition, since the inside of the treatment instrument insertion tube 24 in which the cut hole 241 is formed is smoothed by the film-like member 242, it is possible to more reliably prevent the treatment instrument tip or the like from being caught.

  In addition, the treatment instrument insertion tube 24 at the time of bending is compared with the case where the treatment instrument insertion tube 24 is not eccentric because the treatment instrument insertion tube 24 is arranged at a position eccentric to the curve outer side from the axis BB of the bending portion 32. The radius of curvature increases. In this respect as well, damage to the treatment instrument insertion tube 24 due to the distal end of the treatment instrument can be prevented, and buckling of the treatment instrument insertion tube 24 can also be prevented.

In the above, the configuration in which the flexibility of the inner peripheral side surface portion of the treatment instrument insertion tube is made larger than that of the outer peripheral side surface portion by forming the notch hole is shown. As a structure which is made larger than flexibility, there are materials related to the material and thickness of the inner peripheral side surface portion and the outer peripheral side surface portion. For example, by forming the inner peripheral side surface using a material such as silicon rubber or latex rubber, and forming the outer peripheral side surface using a material such as PTFE, the flexibility of the inner peripheral side surface portion can be increased. It can be made larger than the flexibility of the part.
Further, if the thickness of the inner peripheral side surface portion is made smaller than the thickness of the outer peripheral side surface portion, the flexibility of the inner peripheral side surface portion can be increased as compared with the outer peripheral side surface portion.
Even though these flexible portions formed on the inner peripheral side surface due to the difference in material and thickness are formed at regular intervals in the longitudinal direction of the treatment instrument insertion tube, they are continuously formed. May be.
Similarly, the cut hole formed in the treatment instrument insertion tube in the above-described example may be continuously formed in the longitudinal direction of the treatment instrument insertion tube. That is, the inner peripheral side surface portion of the treatment instrument insertion tube may be greatly opened over the entire curved section, and the treatment instrument insertion tube may be formed in a C-shaped cross section in this opening portion. When such a large cut hole is formed, it is particularly preferable to provide a film-like member.

  In the above-described example, the elastic member made of Ni—Ti alloy or the like is curved on the side opposite to the side where the wire 211 is provided in the curved portion 32, that is, on the position including the curved outer peripheral side with respect to the axis of the curved portion 32. It may extend along the longitudinal direction of the portion 32. This elastic member is interposed between, for example, the curved outer peripheral side portions of the treatment instrument insertion tube 24 and each node ring 321 and the outer skin member 301 constituting the outer peripheral portion of the curved portion 32. Even if only one wire 211 is provided, restoration of the treatment instrument insertion tube 24 and rotation return of the node ring are facilitated by the elastic force of the elastic member, so that the bending portion is quickly restored to a straight line. It becomes possible to make it.

  On the other hand, instead of the wire 211, a long member capable of transmitting a force in the feeding direction opposite to the pulling direction may be provided on the inner side of the bending portion from the axis of the bending portion along the longitudinal direction of the bending portion. It is done. For example, the long member has a cross-sectional area larger than that of the wire (for example, a rectangular cross-section) and is formed as a flexible band-shaped member. By pulling the long member through the operation unit, the bending portion is formed. It is bent and the curved portion is restored to a straight line by pushing the long member.

As described above, the following items are disclosed in this specification.
(1) An endoscope including an insertion portion that encloses a treatment instrument insertion tube,
The insertion portion has a bending portion bent in one direction by a bending operation,
In the bending section that is in a bending state in the treatment instrument insertion tube when the bending portion is bent, the flexibility of the inner peripheral side surface of the treatment instrument insertion tube that becomes the inner peripheral side during bending is An endoscope that is larger than the flexibility of the outer peripheral side surface portion of the treatment instrument insertion tube on the outer peripheral side.
According to this endoscope, since the flexibility of the inner peripheral side surface portion of the treatment instrument insertion tube is increased, the flexibility of the treatment instrument insertion tube at the time of bending can be enhanced, so that the bending portion can be easily bent. Due to the flexibility of the treatment instrument insertion tube, the bending portion can be bent in a compact manner without the treatment instrument insertion tube buckling.

  Here, since the portion having high flexibility is formed on the inner peripheral side surface portion of the treatment instrument insertion tube, the treatment instrument passing through the curved outer peripheral side inside the treatment instrument insertion tube in the curved state is flexible. Therefore, it is difficult to touch the portion where the strength tends to decrease, and the treatment instrument can be inserted into the treatment instrument insertion tube without any trouble. In addition, unlike the case where a plurality of grooves are formed on the entire circumference of the treatment instrument insertion tube, it is easy to maintain the strength of the treatment instrument insertion tube particularly on the curved outer circumference side. Damage to the treatment instrument insertion tube can be prevented. From the above, it is possible to greatly improve the bending performance to such an extent that it can cope with a narrow space in the body cavity without deteriorating usability and reliability.

(2) The endoscope according to (1),
An endoscope in which, in the inner peripheral side surface portion, portions having greater flexibility than the outer peripheral side surface portion are provided at equal intervals in the longitudinal direction of the treatment instrument insertion tube.
According to this endoscope, the flexible portion and the other portion are alternately arranged, so that the effect of being easily bent and the effect of preventing buckling can be obtained satisfactorily.

(3) The endoscope according to (1),
An endoscope in which a portion having greater flexibility than the outer peripheral side surface portion is continuously provided in the longitudinal direction of the treatment instrument insertion tube in the inner peripheral side surface portion.
According to this endoscope, since flexibility is obtained from the entire bending section, it becomes easier to bend.

(4) The endoscope according to any one of (1) to (3),
An endoscope in which a material having greater flexibility than a material used for the outer peripheral side surface portion is used for the inner peripheral side surface portion.
According to this endoscope, the treatment instrument insertion tube can be easily manufactured by two-color molding using materials having different flexibility.

(5) The endoscope according to any one of (1) to (3),
An endoscope in which the thickness of the inner peripheral side surface portion is smaller than the thickness of the outer peripheral side surface portion.
According to this endoscope, the treatment instrument insertion tube can be easily manufactured by extrusion molding or the like.

(6) The endoscope according to any one of (1) to (3),
The inner peripheral side surface portion is formed with a plurality of cut holes that open at intervals in the longitudinal direction of the treatment instrument insertion tube, including a portion that becomes the innermost peripheral side when curved, An endoscope provided with a membrane-like member that closes a plurality of cut holes.
According to this endoscope, the treatment instrument insertion tube is formed by forming the cutting hole that penetrates the treatment instrument insertion tube at a position including the innermost peripheral side when the treatment instrument insertion tube is bent. Therefore, the bending portion can be easily bent. In addition, since the cut hole is blocked by the membrane member, the treatment tool can be easily inserted into the treatment tool insertion tube without hindering the cut hole.

(7) The endoscope according to (6),
The membrane member is an endoscope that is in close contact with the treatment instrument insertion tube.
According to this endoscope, the membranous member is difficult to peel off from the treatment instrument insertion tube, and the tip of the treatment instrument can be prevented from being caught on the edge of the cut hole, thereby improving usability and reliability. Can do.

(8) The endoscope according to (7),
The membrane member is an endoscope having water tightness.
According to this endoscope, even if liquid passes through the treatment instrument insertion tube, liquid leakage does not occur, so that a suction operation via the treatment instrument insertion tube is possible.

(9) The endoscope according to any one of (6) to (8),
The membrane member is an endoscope provided on an inner periphery of the treatment instrument insertion tube.
According to this endoscope, since the inner surface of the treatment instrument insertion tube is smoothed by the membrane member, it is possible to more reliably prevent the treatment instrument from being caught in the cut hole.

(10) The endoscope according to any one of (6) to (9),
The endoscope has a shape in which the width of the gap is the widest on the innermost circumference side when bent, and the width of the gap gradually decreases toward the radially inner side of the treatment instrument insertion tube.
According to this endoscope, since the stress generated in the portion on the bending inner periphery side of the treatment instrument insertion tube during bending can be efficiently reduced, the flexibility of the treatment instrument insertion tube can be further enhanced.

(11) The endoscope according to any one of (1) to (10),
The bending portion is bent in one direction by a bending operation to pull the long member,
The long member is provided only on the curved inner peripheral side with respect to the axis of the curved portion along the longitudinal direction in which the curved portion extends,
The said bending part is an endoscope which has the elastic member extended along the longitudinal direction of the said bending part in the position containing the part of a curve outer peripheral side rather than the said axis.
According to this endoscope, even if only one long member (or several adjacent members) is provided, the bending portion is linearly formed when the long member is released by the elastic force of the elastic member. Can be restored quickly.

(12) The endoscope according to any one of (1) to (10),
The bending portion is bent in one direction by a bending operation to pull the long member,
The elongate member can transmit a force in a feeding direction opposite to the pulling direction, and is provided only on the inner circumferential side of the bending portion along the longitudinal direction along which the bending portion extends. Endoscope.
According to this endoscope, even when the bending direction is limited to one direction, the bending portion is bent by the pulling operation of the long member, and the bending portion is released by the operation of pushing the long member. It becomes possible.

DESCRIPTION OF SYMBOLS 1 Endoscope 2 Universal cable 3 Connector 20 Operation part 21 Angle knob 24 Treatment instrument insertion tube 24A Inner peripheral side face part 24B Outer peripheral side face part 30 Insertion part 31 Flexible part 32 Bending part 33 Tip part 211 Wire 240 Treatment tool insertion port 241 Cut hole 242 Membrane member 301 Outer skin member 320 Pin 321 Node ring 321A Connecting portion 321B Guide pipe C Curved section D Innermost circumference

Claims (13)

An endoscope including an insertion portion that encloses a treatment instrument insertion tube,
The insertion portion has a bending portion bent in one direction by a bending operation,
In the bending section that is in a bending state in the treatment instrument insertion tube when the bending portion is bent, the flexibility of the inner peripheral side surface of the treatment instrument insertion tube that becomes the inner peripheral side during bending is much larger than the flexible peripheral side face of the outer peripheral side the treatment instrument insertion tube, and the higher the endoscope than the rigidity of the peripheral side face is the inner peripheral surface part. The endoscope according to claim 1, wherein
An endoscope in which, in the inner peripheral side surface portion, portions having greater flexibility than the outer peripheral side surface portion are provided at equal intervals in the longitudinal direction of the treatment instrument insertion tube. The endoscope according to claim 1, wherein
An endoscope in which a portion having greater flexibility than the outer peripheral side surface portion is continuously provided in the longitudinal direction of the treatment instrument insertion tube in the inner peripheral side surface portion. The endoscope according to any one of claims 1 to 3,
The said outer peripheral side part is the endoscope made into the smooth continuous shape. The endoscope according to any one of claims 1 to 4, wherein
An endoscope in which a material having greater flexibility than a material used for the outer peripheral side surface portion is used for the inner peripheral side surface portion. The endoscope according to any one of claims 1 to 4, wherein
An endoscope in which the thickness of the inner peripheral side surface portion is smaller than the thickness of the outer peripheral side surface portion. The endoscope according to any one of claims 1 to 4, wherein
The inner peripheral side surface portion is formed with a plurality of cut holes that open at intervals in the longitudinal direction of the treatment instrument insertion tube, including a portion that becomes the innermost peripheral side when curved, An endoscope provided with a membrane-like member that closes a plurality of cut holes. The endoscope according to claim 7, wherein
The membrane member is an endoscope that is in close contact with the treatment instrument insertion tube. The endoscope according to claim 8, wherein
The membrane member is an endoscope having water tightness. The endoscope according to any one of claims 7 to 9,
The membrane member is an endoscope provided on an inner periphery of the treatment instrument insertion tube. The endoscope according to any one of claims 7 to 10,
The endoscope has a shape in which the width of the gap is the widest on the innermost peripheral side during the bending, and the width of the gap gradually decreases toward the radially inner side of the treatment instrument insertion tube. The endoscope according to any one of claims 1 to 11,
The bending portion is bent in one direction by a bending operation to pull the long member,
The long member is provided only on the curved inner peripheral side with respect to the axis of the curved portion along the longitudinal direction in which the curved portion extends,
The said bending part is an endoscope which has the elastic member extended along the longitudinal direction of the said bending part in the position containing the part of a curve outer peripheral side rather than the said axis. The endoscope according to any one of claims 1 to 11,
The bending portion is bent in one direction by a bending operation to pull the long member,
The elongate member can transmit a force in a feeding direction opposite to the pulling direction, and is provided only on the inner circumferential side of the bending portion along the longitudinal direction along which the bending portion extends. Endoscope.

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