Medical guide sheath tube

Abstract

This invention discloses a medical guide sheath, comprising: an inner liner; a reinforcing layer enclosing the inner liner; a sheath layer enclosing the reinforcing layer; a pull cord disposed between the inner liner and the reinforcing layer; a pull ring located in the distal portion of the sheath layer and engaged with the sheath layer; and a pull cord passing through the pull cord, one end of which is connected to the pull ring, and the other end extending from the proximal portion of the sheath layer. The sheath layer has a controllable bending portion adjacent to its distal portion, which can bend under the pull of the pull cord. The controllable bending portion includes multiple sheath segments connected in series along the axial direction of the medical guide sheath, with the end faces of adjacent sheath segments mating and being inclined end faces inclined to the axial direction. In this invention, the mating end faces between the sheath segments are inclined end faces inclined to the axial direction of the medical guide sheath, rather than vertical end faces perpendicular to the axial direction, thereby effectively preventing wrinkles from forming in the bending area of ​​the medical guide sheath and improving the controllability of the medical guide sheath.

Description

Technical Field

[0001] This invention relates to a medical catheter that can be used for implantation or repair surgery of human heart valves. Background Technology

[0002] In existing technologies, medical guide sheaths typically include an inner liner, a pull tube, a pull cord, a reinforcing layer, a pull ring, and a sheath. The reinforcing layer wraps around the inner liner, the sheath wraps around the reinforcing layer, and the pull tube is positioned between the inner liner and the reinforcing layer. The pull cord passes through the pull tube and is connected to the pull ring. The pull ring is located in and engaged with the distal portion of the sheath. The sheath has a controllable bending portion adjacent to its distal portion, comprising multiple sheath segments, each with its end faces perpendicular to the axis of the medical guide sheath. The controllable bending portion of the sheath can bend under the pull of the pull cord, allowing the distal end of the medical guide sheath to bend. However, existing medical guide sheaths are prone to wrinkling in the bending area, which affects the controllability of the medical guide sheath. Summary of the Invention

[0003] The purpose of this invention is to solve at least one aspect of the aforementioned problems and defects existing in the prior art.

[0004] According to one aspect of the present invention, a medical sheath is provided. The medical sheath includes: an inner liner; a reinforcing layer enclosing the inner liner; a sheath layer enclosing the reinforcing layer; a pull cord disposed between the inner liner and the reinforcing layer; a pull ring located in the distal portion of the sheath layer and engaged with the sheath layer; and a pull cord passing through the pull cord, one end of which is connected to the pull ring, and the other end extending from the proximal portion of the sheath layer. The sheath layer has a controllable bending portion adjacent to its distal portion, the controllable bending portion being capable of bending under the pull of the pull cord, the controllable bending portion comprising a plurality of sheath segments connected in series along the axial direction of the medical sheath, the end faces of two adjacent sheath segments cooperating with each other and being inclined end faces inclined to the axial direction.

[0005] According to an exemplary embodiment of the present invention, the hardness of the plurality of sheath segments gradually decreases from the proximal portion of the sheath layer toward the distal portion of the sheath layer, such that the flexibility of the controllable bending portion of the sheath layer gradually increases from the proximal portion to the distal portion.

[0006] According to another exemplary embodiment of the present invention, the sheath segment includes a first sheath segment closest to the distal portion of the sheath layer, a second sheath segment closest to the proximal portion of the sheath layer, and at least one third sheath segment located between the first sheath segment and the second sheath segment; one end face of the third sheath segment is an inclined end face tilted at a first angle relative to the axial direction, and the other end face of the third sheath segment is an inclined end face tilted at a second angle relative to the axial direction, and the sum of the first angle and the second angle is equal to degrees.

[0007] According to another exemplary embodiment of the present invention, the controllable bending portion includes a plurality of third sheath segments, the plurality of third sheath segments being identical in size and shape.

[0008] According to another exemplary embodiment of the invention, the sheath segment has a first side that is longest in the axial direction and a second side that is shortest in the axial direction, the first side and the second side being radially opposite to the medical guide sheath, and the first side of the second sheath segment being adjacent to and facing the pull tube.

[0009] According to another exemplary embodiment of the present invention, the hardness of the plurality of sheath segments of the controllable bending portion gradually decreases from the proximal portion of the sheath layer toward the distal portion of the sheath layer, such that the flexibility of the controllable bending portion of the sheath layer gradually increases from the proximal portion to the distal portion; the hardness of the proximal portion of the sheath layer is greater than the hardness of the second sheath segment, and the hardness of the first sheath segment is greater than the hardness of the distal portion of the sheath layer.

[0010] According to another exemplary embodiment of the present invention, one end face of the first sheath segment is an inclined end face that is tilted relative to the axial direction by the first angle or the second angle, and the other end face of the first sheath segment is a vertical end face that is perpendicular to the axial direction; the inclined end face of the first sheath segment mates with an inclined end face of the third sheath segment, and the distal portion of the sheath layer has a first vertical end face that mates with the vertical end face of the first sheath segment.

[0011] According to another exemplary embodiment of the present invention, one end face of the first sheath segment is an inclined end face tilted at the first angle relative to the axial direction, and the other end face of the first sheath segment is an inclined end face tilted at the second angle relative to the axial direction; and one inclined end face of the first sheath segment mates with one inclined end face of the third sheath segment, and the distal portion of the sheath layer has a first inclined end face mates with the other inclined end face of the first sheath segment.

[0012] According to another exemplary embodiment of the present invention, one end face of the second sheath segment is an inclined end face tilted at the first angle relative to the axial direction, and the other end face of the second sheath segment is an inclined end face tilted at the second angle relative to the axial direction, and the proximal portion of the sheath layer has a second inclined end face that mates with one inclined end face of the second sheath segment.

[0013] According to another exemplary embodiment of the present invention, one end face of the second sheath segment is an inclined end face that is tilted relative to the axial direction by the first angle or the second angle, and the other end face of the second sheath segment is a vertical end face that is perpendicular to the axial direction; the inclined end face of the second sheath segment mates with an inclined end face of the third sheath segment, and the proximal portion of the sheath layer has a second vertical end face that mates with the vertical end face of the second sheath segment.

[0014] According to another exemplary embodiment of the invention, the reinforcing layer extends to the rear end of the distal portion of the sheath layer, and the pull ring is located outside the reinforcing layer and axially abuts against the front end face of the reinforcing layer.

[0015] According to another exemplary embodiment of the present invention, a lead hole is formed on the proximal portion of the reinforcing layer and the sheath layer to allow the pull wire to be led out, the pull wire tube extends from the rear end of the distal portion of the sheath layer to the lead hole, and the pull wire is led out from the lead hole.

[0016] According to another exemplary embodiment of the present invention, the medical sheath further includes a heat-shrink tubing, which is fitted and heat-shrinked onto the sheath layer to heat-shrink the sheath layer, the reinforcing layer, the draw tube, and the inner lining layer together, wherein the proximal portion, the distal portion, and the controllable bending portion of the sheath layer are axially connected together via the heat-shrink tubing.

[0017] According to another exemplary embodiment of the present invention, the inner lining is a flexible layer made of polytetrafluoroethylene, and the reinforcing layer is a braided metal wire layer or a serpentine flexible metal tube.

[0018] According to another exemplary embodiment of the present invention, the proximal portion of the sheath layer, a plurality of sheath segments of the controllable bending portion of the sheath layer, and the distal portion of the sheath layer are each formed of polymers with different hardnesses; the proximal portion of the sheath layer has the highest hardness, the distal portion of the sheath layer has the lowest hardness, and the hardness of the plurality of sheath segments of the controllable bending portion of the sheath layer gradually decreases from the proximal portion to the distal portion.

[0019] In the aforementioned exemplary embodiments of the present invention, the mating end faces between the controllable bending portions of the sheath layer of the medical guide sheath are inclined end faces that are inclined to the axial direction of the medical guide sheath, rather than vertical end faces that are perpendicular to the axial direction of the medical guide sheath. This effectively prevents wrinkles from forming in the bending area of ​​the medical guide sheath and improves the controllability of the medical guide sheath.

[0020] Other objects and advantages of the invention will become apparent from the following description of the invention with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the invention. Attached Figure Description

[0021] Figure 1 This diagram shows a three-dimensional view of a medical sheath according to an exemplary embodiment of the present invention.

[0022] Figure 2 A radial cross-sectional view of a medical guide sheath according to an exemplary embodiment of the present invention is shown;

[0023] Figure 3 This shows an axial cross-sectional view of a medical guide sheath according to an exemplary embodiment of the present invention;

[0024] Figure 4 This diagram shows an exploded view of a medical sheath according to an exemplary embodiment of the present invention.

[0025] Figure 5 A perspective view showing the sheath layer of a medical sheath according to an exemplary embodiment of the present invention;

[0026] Figure 6 This diagram shows an exploded view of the sheath layer of a medical sheath according to an exemplary embodiment of the present invention.

[0027] Figure 7 This is an exploded planar schematic diagram showing the sheath layer of a medical sheath according to an exemplary embodiment of the present invention;

[0028] Figure 8 This is an exploded planar schematic diagram showing the sheath layer of a medical sheath according to another exemplary embodiment of the present invention;

[0029] Figure 9 show Figure 8 A schematic diagram of the sheath layer of a medical catheter shown;

[0030] Figure 10 This is an exploded planar schematic diagram showing the sheath layer of a medical sheath according to another exemplary embodiment of the present invention;

[0031] Figure 11 show Figure 10The diagram shows a planar schematic of the sheath layer of a medical catheter. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.

[0033] Furthermore, in the following detailed description, numerous specific details are set forth for ease of explanation to provide a thorough understanding of the embodiments disclosed herein. However, it will be apparent that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and apparatuses are illustrated to simplify the figures.

[0034] According to a general technical concept of the present invention, a medical guide sheath is provided. The medical guide sheath includes: an inner liner; a reinforcing layer enclosing the inner liner; a sheath layer enclosing the reinforcing layer; a pull cord disposed between the inner liner and the reinforcing layer; a pull ring located in the distal portion of the sheath layer and engaged with the sheath layer; and a pull cord passing through the pull cord, one end of which is connected to the pull ring, and the other end extending from the proximal portion of the sheath layer. The sheath layer has a controllable bending portion adjacent to its distal portion, the controllable bending portion being capable of bending under the pull of the pull cord, the controllable bending portion comprising a plurality of sheath segments connected in series along the axial direction of the medical guide sheath, the end faces of two adjacent sheath segments cooperating with each other and being inclined end faces inclined to the axial direction.

[0035] Figure 1 This diagram shows a three-dimensional view of a medical sheath according to an exemplary embodiment of the present invention. Figure 2 A radial cross-sectional view of a medical guide sheath according to an exemplary embodiment of the present invention is shown; Figure 3 This shows an axial cross-sectional view of a medical guide sheath according to an exemplary embodiment of the present invention; Figure 4 This diagram shows an exploded view of a medical sheath according to an exemplary embodiment of the present invention. Figure 5 A perspective view showing the sheath layer 3 of a medical sheath tube according to an exemplary embodiment of the present invention; Figure 6 An exploded view of the sheath layer 3 of a medical sheath tube according to an exemplary embodiment of the present invention is shown. Figure 7 This diagram shows an exploded planar view of the sheath layer 3 of a medical sheath tube according to an exemplary embodiment of the present invention.

[0036] like Figures 1 to 7As shown, in an exemplary embodiment of the present invention, a medical guide sheath is disclosed. The medical guide sheath includes: an inner liner 1, a reinforcing layer 2, a sheath layer 3, a pull tube 4, a pull ring 5, and a pull line 6. The reinforcing layer 2 encloses the inner liner 1. The sheath layer 3 encloses the reinforcing layer 2. The pull tube 4 is disposed between the inner liner 1 and the reinforcing layer 2. The pull ring 5 is located in the distal portion 31 of the sheath layer 3 and is engaged with the sheath layer 3. The pull line 6 passes through the pull tube 4, with one end connected to the pull ring 5 and the other end leading out from the proximal portion 32 of the sheath layer 3. The sheath layer 3 has a controllable bending portion 33 adjacent to its distal portion 31, which is capable of bending under the pull of the pull line 6. The controllable bending portion 33 includes a plurality of sheath segments 30 connected in series axially in the medical guide sheath, the end faces of two adjacent sheath segments 30 cooperating with each other and being inclined end faces 30a inclined to the axial direction of the medical guide sheath.

[0037] like Figures 1 to 7 As shown, in the illustrated embodiment, the hardness of the plurality of sheath segments 30 gradually decreases from the proximal portion 32 of the sheath layer 3 toward the distal portion 31 of the sheath layer 3, thereby making the flexibility of the controllable bending portion 33 of the sheath layer 3 gradually increase from the proximal portion 32 toward the distal portion 31.

[0038] like Figures 1 to 7 As shown in the illustrated embodiment, the sheath segment 30 includes a first sheath segment 301 closest to the distal portion 31 of the sheath layer 3, a second sheath segment 302 closest to the proximal portion 32 of the sheath layer 3, and at least one third sheath segment 303 located between the first sheath segment 301 and the second sheath segment 302. One end face of the third sheath segment 303 is an inclined end face 30a inclined at a first angle α relative to the axial direction, and the other end face of the third sheath segment 303 is an inclined end face 30a inclined at a second angle β relative to the axial direction, and the sum of the first angle α and the second angle β is equal to 180 degrees.

[0039] like Figures 1 to 7 As shown in the illustrated embodiment, the controllable bending portion 33 includes a plurality of third sheath segments 303, all of which are identical in size and shape. This reduces the number of manufacturing molds required, thereby lowering manufacturing costs.

[0040] like Figures 1 to 7 As shown, in the illustrated embodiment, the sheath segment 30 has a first side 30c that is the longest in the axial direction and a second side 30d that is the shortest in the axial direction. The first side 30c and the second side 30d are opposite each other in the radial direction of the medical guide sheath. The first side 30c of the second sheath segment 302 is adjacent to and faces the pull tube 4.

[0041] like Figures 1 to 7As shown in the illustrated embodiment, the hardness of the plurality of sheath segments 30 of the controllable bending portion 33 gradually decreases from the proximal portion 32 of the sheath layer 3 towards the distal portion 31 of the sheath layer 3, thereby gradually increasing the flexibility of the controllable bending portion 33 of the sheath layer 3 from the proximal portion 32 to the distal portion 31. The hardness of the proximal portion 32 of the sheath layer 3 is greater than the hardness of the second sheath segment 302, and the hardness of the first sheath segment 301 is greater than the hardness of the distal portion 31 of the sheath layer 3.

[0042] like Figures 1 to 7 As shown in the illustrated embodiment, one end face of the first sheath segment 301 is an inclined end face 30a tilted at a first angle α or a second angle β relative to the axial direction, and the other end face of the first sheath segment 301 is a vertical end face 30b perpendicular to the axial direction. The inclined end face 30a of the first sheath segment 301 mates with an inclined end face 30a of the third sheath segment 303, and the distal portion 31 of the sheath layer 3 has a first vertical end face 31b that mates with the vertical end face 30b of the first sheath segment 301.

[0043] Figure 8 An exploded planar schematic diagram showing the sheath layer 3 of a medical sheath according to another exemplary embodiment of the present invention; Figure 9 show Figure 8 The diagram shows a planar schematic of the sheath layer 3 of the medical guide sheath.

[0044] Figure 8 and Figure 9 The medical sheath shown Figures 1 to 7 The only difference between the medical sheaths shown is the structure of the first sheath section 301. For example... Figure 8 and Figure 9 As shown in the illustrated embodiment, one end face of the first sheath segment 301 is an inclined end face 30a tilted at a first angle α relative to the axial direction, and the other end face of the first sheath segment 301 is an inclined end face 30a tilted at a second angle β relative to the axial direction. One inclined end face 30a of the first sheath segment 301 mates with one inclined end face 30a of the third sheath segment 303, and the distal portion 31 of the sheath layer 3 has a first inclined end face 31a that mates with the other inclined end face 30a of the first sheath segment 301.

[0045] like Figures 1 to 7 As shown in the illustrated embodiment, one end face of the second sheath segment 302 is an inclined end face 30a that is tilted at a first angle α relative to the axial direction, and the other end face of the second sheath segment 302 is an inclined end face 30a that is tilted at a second angle β relative to the axial direction. The proximal portion 32 of the sheath layer 3 has a second inclined end face 32a that mates with one inclined end face 30a of the second sheath segment 302.

[0046] Figure 10An exploded planar schematic diagram showing the sheath layer 3 of a medical sheath according to another exemplary embodiment of the present invention; Figure 11 show Figure 10 The diagram shows a planar schematic of the sheath layer 3 of the medical guide sheath.

[0047] Figure 10 and Figure 11 The medical sheath shown Figure 8 and Figure 9 The only difference between the medical sheaths shown is the structure of the second sheath section 302. For example... Figure 10 and Figure 11 As shown in the illustrated embodiment, one end face of the second sheath segment 302 is an inclined end face 30a tilted at a first angle α or a second angle β relative to the axial direction, and the other end face of the second sheath segment 302 is a vertical end face 30b perpendicular to the axial direction. The inclined end face 30a of the second sheath segment 302 mates with an inclined end face 30a of the third sheath segment 303, and the proximal portion 32 of the sheath layer 3 has a second vertical end face 32b that mates with the vertical end face 30b of the second sheath segment 302.

[0048] like Figures 1 to 10 As shown in the illustrated embodiment, the reinforcing layer 2 extends to the rear end of the distal portion 31 of the sheath layer 3, and the pull ring 5 is located outside the reinforcing layer 2 and axially abuts against the front end face of the reinforcing layer 2.

[0049] like Figures 1 to 10 As shown in the illustrated embodiment, a lead hole 3a is formed on the proximal portion 32 of the reinforcing layer 2 and the sheath layer 3 to allow the pull wire 6 to be led out. The pull tube 4 extends from the rear end of the distal portion 31 of the sheath layer 3 to the lead hole 3a, and the pull wire 6 is led out from the lead hole 3a.

[0050] like Figures 1 to 10 As shown in the illustrated embodiment, the medical sheath also includes a heat-shrink tubing (not shown), which is fitted and heat-shrinked onto the sheath layer 3 to heat-shrink the sheath layer 3, reinforcing layer 2, pull tube 4, and inner liner layer 1 together. The proximal portion 32, distal portion 31, and controllable bend portion 33 of the sheath layer 3 are axially connected together via the heat-shrink tubing.

[0051] like Figures 1 to 10 As shown in the illustrated embodiment, the inner lining layer 1 can be a flexible layer made of polytetrafluoroethylene, and the reinforcing layer 2 can be a metal wire braided layer or a serpentine flexible metal tube.

[0052] like Figures 1 to 10As shown in the illustrated embodiment, the proximal portion 32 of the sheath layer 3, the plurality of sheath segments 30 of the controllable bending portion 33 of the sheath layer 3, and the distal portion 31 of the sheath layer 3 are formed of polymers with different hardnesses. The proximal portion 32 of the sheath layer 3 has the highest hardness, the distal portion 31 of the sheath layer 3 has the lowest hardness, and the hardness of the plurality of sheath segments 30 of the controllable bending portion 33 of the sheath layer 3 gradually decreases from the proximal portion 32 to the distal portion 31.

[0053] This invention aims to design the bending region of the sheath layer 3 with an asymmetrical structure, making the outer side of the bending region of the sheath layer 3 easier to stretch, while the inner side is easier to contract. This novel design minimizes the risk of wrinkling in the bending region of the medical guide sheath. The controllable bending portion of the sheath layer in this invention smoothly transitions from hard to soft, which contributes to better steering performance and prevents any sudden and uneven deformation. Furthermore, this invention allows for a smaller turning radius without altering the overall dimensions of the medical guide sheath. The solution of this invention does not require significant modifications to existing manufacturing processes, offering cost-effectiveness and suitability for mass production.

[0054] Those skilled in the art will understand that the embodiments described above are exemplary and can be improved upon. The structures described in the various embodiments can be freely combined without causing structural or principle conflicts, and these changes should fall within the protection scope of this invention.

[0055] Although the invention has been described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to illustrate preferred embodiments of the invention and should not be construed as limiting the invention.

[0056] While some embodiments of the general concept of the invention have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the general concept of the invention, the scope of which is defined by the claims and their equivalents.

[0057] It should be noted that the word "comprising" does not exclude other elements or steps, and the words "a" or "an" do not exclude multiple elements. Furthermore, any reference numerals in the claims should not be construed as limiting the scope of the invention.

Claims

1. A medical guiding sheath, characterized in that, include: Inner lining (1); A reinforcing layer (2) surrounds the inner lining layer (1); Sheath layer (3) wraps around the reinforcing layer (2); A cable guide (4) is disposed between the inner lining layer (1) and the reinforcing layer (2); A pull ring (5) is located in the distal portion (31) of the sheath layer (3) and is engaged with the sheath layer (3); and A pull wire (6) passes through the pull tube (4) and is connected at one end to the pull ring (5), with the other end extending from the proximal portion (32) of the sheath layer (3). The sheath layer (3) has a controllable bending portion (33) adjacent to its distal portion (31), the controllable bending portion (33) being able to bend under the pull of the pull wire (6). The controllable bending portion (33) includes multiple sheath segments (30) connected in series along the axial direction of the medical guide sheath, with the end faces of two adjacent sheath segments (30) cooperating with each other and being inclined end faces (30a) inclined to the axial direction.

2. The medical guide sheath according to claim 1, characterized in that: The hardness of the plurality of sheath segments (30) gradually decreases from the proximal portion (32) of the sheath layer (3) toward the distal portion (31) of the sheath layer (3), such that the flexibility of the controllable bending portion (33) of the sheath layer (3) gradually increases from the proximal portion (32) toward the distal portion (31).

3. The medical guide sheath according to claim 1, characterized in that: The sheath segment (30) includes a first sheath segment (301) closest to the distal portion (31) of the sheath layer (3), a second sheath segment (302) closest to the proximal portion (32) of the sheath layer (3), and at least one third sheath segment (303) located between the first sheath segment (301) and the second sheath segment (302); One end face of the third sheath segment (303) is an inclined end face (30a) tilted at a first angle (α) relative to the axial direction, and the other end face of the third sheath segment (303) is an inclined end face (30a) tilted at a second angle (β) relative to the axial direction, and the sum of the first angle (α) and the second angle (β) is equal to 180 degrees.

4. The medical guide sheath according to claim 3, characterized in that: The controllable bending portion (33) includes a plurality of third sheath segments (303), which are identical in size and shape.

5. The medical guide sheath according to claim 3, characterized in that: The sheath segment (30) has a first side (30c) that is longest in the axial direction and a second side (30d) that is shortest in the axial direction. The first side (30c) and the second side (30d) are opposite each other in the radial direction of the medical guide sheath. The first side (30c) of the second sheath segment (302) is adjacent to and faces the pull tube (4).

6. The medical guide sheath according to claim 3, characterized in that: The hardness of the multiple sheath segments (30) of the controllable bending portion (33) gradually decreases from the proximal portion (32) of the sheath layer (3) toward the distal portion (31) of the sheath layer (3), so that the flexibility of the controllable bending portion (33) of the sheath layer (3) gradually increases from the proximal portion (32) to the distal portion (31). The hardness of the proximal portion (32) of the sheath layer (3) is greater than the hardness of the second sheath segment (302), and the hardness of the first sheath segment (301) is greater than the hardness of the distal portion (31) of the sheath layer (3).

7. The medical guide sheath according to claim 3, characterized in that: One end face of the first sheath segment (301) is an inclined end face (30a) that is inclined relative to the axial direction by the first angle (α) or the second angle (β), and the other end face of the first sheath segment (301) is a vertical end face (30b) that is perpendicular to the axial direction. The inclined end face (30a) of the first sheath segment (301) mates with an inclined end face (30a) of the third sheath segment (303), and the distal portion (31) of the sheath layer (3) has a first vertical end face (31b) that mates with the vertical end face (30b) of the first sheath segment (301).

8. The medical guide sheath according to claim 3, characterized in that: One end face of the first sheath segment (301) is an inclined end face (30a) tilted at the first angle (α) relative to the axial direction, and the other end face of the first sheath segment (301) is an inclined end face (30a) tilted at the second angle (β) relative to the axial direction; and One inclined end face (30a) of the first sheath segment (301) mates with one inclined end face (30a) of the third sheath segment (303), and the distal portion (31) of the sheath layer (3) has a first inclined end face (31a) that mates with another inclined end face (30a) of the first sheath segment (301).

9. The medical sheath according to any one of claims 3 to 8, characterized in that: One end face of the second sheath segment (302) is an inclined end face (30a) tilted at the first angle (α) relative to the axial direction, and the other end face of the second sheath segment (302) is an inclined end face (30a) tilted at the second angle (β) relative to the axial direction. The proximal portion (32) of the sheath layer (3) has a second inclined end face (32a) that mates with one inclined end face (30a) of the second sheath segment (302).

10. The medical sheath according to any one of claims 3 to 8, characterized in that: One end face of the second sheath segment (302) is an inclined end face (30a) that is inclined relative to the axial direction by the first angle (α) or the second angle (β), and the other end face of the second sheath segment (302) is a vertical end face (30b) that is perpendicular to the axial direction. The inclined end face (30a) of the second sheath segment (302) mates with an inclined end face (30a) of the third sheath segment (303), and the proximal portion (32) of the sheath layer (3) has a second vertical end face (32b) that mates with the vertical end face (30b) of the second sheath segment (302).

11. The medical guide sheath according to claim 1, characterized in that: The reinforcing layer (2) extends to the rear end of the distal portion (31) of the sheath layer (3), and the pull ring (5) is located outside the reinforcing layer (2) and axially abuts against the front end surface of the reinforcing layer (2).

12. The medical guide sheath according to claim 1, characterized in that: A lead hole (3a) is formed on the proximal portion (32) of the reinforcing layer (2) and the sheath layer (3) to allow the pull wire (6) to be led out. The pull tube (4) extends from the rear end of the distal portion (31) of the sheath layer (3) to the lead hole (3a), and the pull wire (6) is led out from the lead hole (3a).

13. The medical guide sheath according to claim 1, characterized in that, Also includes: Heat shrink tubing is fitted and heat-shrinked onto the sheath layer (3) to heat-shrink the sheath layer (3), the reinforcing layer (2), the draw tube (4), and the inner lining layer (1) together. The proximal portion (32), distal portion (31), and controllable bending portion (33) of the sheath layer (3) are axially connected together via the heat shrink tubing.

14. The medical guide sheath according to claim 1, characterized in that: The inner lining layer (1) is a flexible layer made of polytetrafluoroethylene, and the reinforcing layer (2) is a metal wire braided layer or a serpentine flexible metal tube.

15. The medical guide sheath according to claim 1, characterized in that: The proximal portion (32) of the sheath layer (3), the multiple sheath segments (30) of the controllable bending portion (33) of the sheath layer (3) and the distal portion (31) of the sheath layer (3) are formed of polymers with different hardness. The hardness of the proximal portion (32) of the sheath layer (3) is the greatest, and the hardness of the distal portion (31) of the sheath layer (3) is the least. The hardness of the multiple sheath segments (30) of the controllable bending portion (33) of the sheath layer (3) gradually decreases from the proximal portion (32) to the distal portion (31).

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