JP2016000115A - Medical knife and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-blade medical knife with two blade bodies fixed permanently on a handle and exposing a part of a blade tip including a front end part, or favorably exposing half of the length which the blade tip is projected on a straight line in a longitudinal direction or more or less.SOLUTION: A cavity 52 is formed in a front part of a handle 2. The cavity 52 is surrounded by peripheral walls 47 and has an opening on a front side. The peripheral walls 47 include upper walls 50, lower walls 51, and a pair of facing side walls 8, 27. Two blade bodies 3, 3 are fixed on an inner face of the side walls 8, 27 respectively and projected from the opening. The handle 2 is favorably constituted by combining two half-split bodies 6, 7.

Description

  The present invention relates to a medical knife in which two blade bodies are attached to a front portion of a handle in parallel with a gap therebetween.

  A two-blade medical knife with two blades attached in parallel at a distance is a knife mainly used to cut tissue to a predetermined width, for example, anterior cruciate ligament reconstruction of the knee Used for cutting the patella tendon while maintaining the distance between the blades, cutting the tibial plug or patella plug when cutting them, or extracting the tissue with a predetermined width Is a medical knife.

  Such a two-blade medical knife is described in Patent Document 1, for example. In this medical knife, two blade bodies are fixed to both extension portions 11 projecting to the front side of the handle. Further, the back portion 17, that is, the upper wall is formed in the latter half portion of both the extended portions, but the lower wall facing the back portion is not formed. That is, it does not have a cavity surrounded by a peripheral wall including a pair of side walls to which the blade body is to be fixed at the front end of the handle. Therefore, there is no lower wall for covering the lower edge of the attached blade body, and the blade edge is exposed over the entire length.

  The two-blade medical knife described above is a disposable knife whose blade is permanently fixed to the handle, but there is no dedicated blade for this knife. For example, Japanese Patent Laid-Open No. 9-75363 discloses A replaceable blade type single blade medical knife as described is used. As described in FIG. 5 of JP-A-9-75363, this replaceable blade has a sharp blade edge formed from the front end of the blade body to a position slightly exceeding half of the entire length of the blade body. The cutting edge is formed up to this position because when using a single blade replaceable knife type scalpel, the cutting edge is used not only near the front end but also up to the center of the blade body. is there. On the other hand, since the two-blade medical knife is used for cutting the patella tendon or making a cut in the bone as described above, a portion closer to the front end of the blade edge is used. Therefore, in the two-blade medical knife of the present invention, it is not necessary to expose almost the entire length of the cutting edge as in Patent Document 1, for example, the first half of the cutting edge, that is, half the length of the cutting edge projected onto a straight line in the longitudinal direction. It is enough to expose to some extent. In this way, since the unnecessary blade edge is not exposed, the possibility of damaging a finger or the like with the blade edge can be reduced.

US Pat. No. 5,100,391 JP-A-9-75363

  The present invention is a two-blade medical knife in which two blade bodies are fixed to a handle, and includes a part including the front end portion of the blade edge, preferably about half of the length projected on the straight line in the longitudinal direction. An object is to provide an exposed two-blade medical knife.

According to the first aspect of the present invention, a cavity is formed in the front portion of the handle, the cavity is surrounded by a peripheral wall and has an opening in the front, and the peripheral wall includes an upper wall, a lower wall, and a pair of opposite side walls, The two blades are fixed to the inner surfaces of their side walls and protrude from the opening.

The invention according to claim 2 is a configuration in which all of the upper wall, the lower wall, and the pair of side walls of the peripheral wall cover a portion of 40% or more of the entire length of the blade body from the rear end of the attached blade body. .

The invention according to claim 3 is configured such that the handle is formed by joining two halves, and each of the halves has a side wall and an upper wall and a lower wall of the half. is there.

According to a fourth aspect of the present invention, elongated holes are formed in the blade bodies, and convex portions that fit into the elongated holes are formed on the side walls to which the blade bodies are to be fixed. The blade is fixed to the side wall by forming a protruding portion in the width direction by crushing and forming the protruding portion of the convex portion protruding from the long hole of the blade body. It is a configuration.

The invention according to claim 5 is a configuration in which the handle is formed vertically symmetrically with respect to a center line extending in the longitudinal direction in a side view of the handle placed horizontally.

The invention according to claim 6 is configured such that a finger rest concave surface is formed on the surface of the upper wall and the surface of the lower wall, and these finger rest concave surfaces overlap with a position of a part of the attached blade body. .

The invention according to claim 7 is a configuration in which the finger placement concave surface is overlapped with a center in the longitudinal direction of the blade body or a position ahead thereof.

In the invention according to claim 8, a cavity is formed in the front portion of the handle, the cavity is surrounded by a peripheral wall and has an opening in the front, and the two blade bodies are parallel to each other with an interval on the inner surface of the peripheral wall. A method of manufacturing a medical knife that is fixed to each other and protrudes from an opening, wherein two elongated handle parts having a peripheral wall constituting part that constitutes a peripheral wall at the front part are formed, and then each of the peripheral wall constituent parts is formed. The blade body is fixed at a predetermined position on the inner surface, and then both handle parts are coupled so that the respective peripheral wall components cooperate to form a cavity.

  As described above, there is no special blade for the knife of the present invention, and a replaceable blade type single-blade medical knife replacement blade is mainly used. However, for the two-blade medical knife of the present invention, this replaceable blade has a sharp blade edge that is longer than necessary, and the length of the blade edge that is exposed to reduce the possibility of damaging the finger is obstructed. It is preferable to shorten the length within a range that does not cause the problem. According to the first aspect of the present invention, a cavity is formed in the front portion of the handle, the cavity is surrounded by a peripheral wall and has an opening in the front, and the peripheral wall includes an upper wall, a lower wall, and a pair of opposite side walls, Since the two blade bodies are fixed to the inner surfaces of their side walls and protrude from the opening, a part of the blade body is surrounded by the peripheral wall. Thereby, when the blade body which has a blade edge longer than necessary is used, the exposure of the blade edge can be shortened. For example, when a replaceable blade of a single-blade medical knife is used for the double-blade medical knife of the present invention, a single-blade medical device having a cutting edge longer than necessary for the double-blade medical knife. A knife replacement blade can be used having a cutting edge length suitable for a two-blade medical knife. In this way, by shortening the length of the exposed blade edge, the possibility of damaging the finger during surgery can be reduced. Furthermore, since the two blade bodies are respectively fixed to the inner surface of the side wall, when the fingertip is applied to the outer surface of the side wall during use, the fingertip does not touch the blade body and is safe. Since the protrusion for fixing the blade does not protrude, the finger is not disturbed during use.

  When performing fine work using the two-blade medical knife of the present invention, when the fingertip of the hand holding the handle is placed on the surface of the handle, it overlaps with the position of a part of the attached blade body. It is possible to perform stable work by placing them in such a manner. In the invention according to claim 2, since all of the upper wall, the lower wall and the pair of side walls of the peripheral wall cover 40% or more of the entire length of the blade body from the rear end of the attached blade body, Even when the fingertip is placed on any part of the throat, the fingertip overlaps a part of the blade body, and fine work can be performed in a stable state.

  The double-edged medical knife described in Patent Document 1 is not a combination of half handle parts, but is integrally formed by injection molding. It may be difficult in the mold release process to integrally form a handle having an opening at the front portion by injection molding as in the present invention. Therefore, the handle of Patent Document 1 is configured not to be a cavity surrounded by a peripheral wall, but to expose the lower edge of the blade body over the entire length without surrounding the front part of the handle with the peripheral wall. In order to provide a cavity in a handle integrally molded by injection molding, it is possible to cut the cavity from the front end of the handle after molding, but this method is actually difficult to use because it takes time. Furthermore, in order to cover a part of the blade edge of the blade body without providing a cavity, it is conceivable to attach the blade body by insert molding. In this case, since the portion covering the blade body becomes thick, This part shrinks, and a dent called a sink is formed on the surface, or a bubble is formed in the center of the thick part. On the other hand, in the invention according to claim 3, the handle is constituted by joining two halves, and each half is formed with one side wall and upper and lower walls of the half. Has been. Therefore, since there is no cavity surrounded by a peripheral wall in the half body, each half body can be easily molded by injection molding, and a handle having a cavity can be easily formed by simply joining the two half bodies. Can be manufactured.

  As described above, the blade body used in the present invention is mainly a replaceable blade of a replaceable blade type single blade medical knife. A long hole is formed in the replacement blade, and the long hole can be detachably attached to the handle of the single-blade medical knife. The invention according to claim 4 is mainly configured to use the replacement blade of the single-blade medical knife, and the blade body having the long hole is fitted into the long hole on the side wall to be fixed. A convex part is formed, and the convex part is formed higher than the thickness of the blade, and the protruding part of the convex part protruding from the long hole of the blade is crushed and formed to form a protruding part in the width direction. By doing so, the blade body is fixed to the side wall. That is, fixing the blade body by fitting a long hole to the convex portion formed on the side wall of the half of the handle, and then crushing and forming the convex portion to form a protruding portion in the width direction Can do. Therefore, the blade body can be fixed to the inner surface of the side wall of the cavity of the handle by a very simple process.

  The invention described in claim 5 is such that the outer shape of the handle is vertically symmetrical with respect to a center line extending in the longitudinal direction in a side view of the handle placed horizontally. Therefore, after performing a cutting operation by moving the knife in a predetermined direction during the operation, the cutting edge of the blade body is directed in the reverse direction when the cutting operation is performed by moving the knife in a direction almost opposite to that direction. In this way, when the handle is reversed and the knife is changed, the handle grasped by the hand does not change in shape from the first grasped state, so that the operation can be continued without any sense of incongruity.

  When performing fine work using a medical knife during a surgical operation, the fingertip placed on the handle is more stable closer to where the cut is actually made. According to the sixth aspect of the present invention, the finger rest concave surfaces are formed on the surface of the upper wall and the surface of the lower wall, and these finger rest concave surfaces overlap with the position of a part of the attached blade body. Can be placed near the place where the cutting is performed, so that an accurate and stable operation can be performed.

  According to the seventh aspect of the present invention, the finger placement concave surface overlaps with the center in the longitudinal direction of the blade body or a position ahead thereof. Therefore, since the fingertip can be placed very close to the place where the cutting is performed, a more accurate and stable operation can be performed.

  In the invention according to claim 8, a cavity is formed in the front portion of the handle, the cavity is surrounded by a peripheral wall and has an opening in the front, and the two blade bodies are parallel to each other with an interval between the inner surfaces of the peripheral wall. A method of manufacturing a medical knife that is fixed to each other and protrudes from the opening, wherein two elongated handle parts having a peripheral wall constituting part constituting the peripheral wall are formed at a front part, and then each peripheral wall structure is formed. In this method, the blades are fixed at predetermined positions on the inner surface of the part, and then both handle parts are joined so that the respective peripheral wall constituting parts cooperate to form a cavity. When the handle is molded in one piece without halving it, it may be difficult to remove the mold from the cavity surrounded by the peripheral wall, and there is a drawback that it is difficult to mold. On the other hand, if the handle is divided into two handle parts and combined later, there is no need to form a cavity surrounded by a peripheral wall on the entire periphery, and a peripheral wall is formed on each handle part. When the peripheral wall component is formed to form a half of the cavity in each handle part, and when the handle parts are joined, the two peripheral wall components are joined together so that each half of the cavity is joined and surrounded by the peripheral wall A cavity is formed. Therefore, the invention according to claim 8 is easy to mold because it does not include a step of molding a cavity surrounded by a peripheral wall on the entire circumference. In addition, when a method is adopted in which both handle parts are joined to form a cavity in the front part of the handle and then the blade body is fixed in the cavity, the work space in the cavity surrounded by the peripheral wall is adopted. It is difficult to fix the blade body. In the present invention, since the blade body is fixed to the peripheral wall constituting portion of the handle part before joining, there is a large margin in the work space, and the blade body can be easily fixed using a machine.

FIG. 1 is a side view of the present invention. FIG. 2 is a top view of the present invention. FIG. 3 is an AA enlarged sectional view in FIG. 4 is a cross-sectional view taken along the line BB in FIG. FIG. 5 is a perspective view of one half of the handle. FIG. 6 is a perspective view of the other half of the handle. FIG. 7 is an inner view of the half body showing a state in which the blade body is fitted to one half body. FIG. 8 is an inner surface view of the half body showing a state in which the blade is fixed by crushing and forming the convex portion from the state of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The knife 1 of the present invention is fixed to the front end of an elongated handle 2 so that two blade bodies 3 and 3 protrude in parallel. As shown in FIG. 1, the outer shape of the handle 2 is formed vertically symmetrically with respect to a center line extending in a longitudinal direction in a side view of the handle 2 placed horizontally, that is, a BB line. A finger rest concave surface 4 is formed near the front end of the upper surface of the handle 2, and a finger rest concave surface 5 is formed on the lower surface.

  The handle 2 is not formed by integral molding, but is formed by separately molding the two halves 6 and 7 separately and connecting them. As shown in FIG. 5, one half 6 rises from the edge of the side wall 8 so that the upper wall 9, the lower wall 10 and the rear wall 11 of the half are continuous. The side wall 8 and the upper wall 9 and the lower wall 10 of the half are extended over almost the entire length of the half 6, whereby a groove 45 extending in the longitudinal direction is formed in the half 6. A step surface 12 extends on the inner surfaces of the continuous upper wall 9, lower wall 10 and rear wall 11, and a predetermined number of fitting recesses 13 are formed at predetermined positions on the step surface 12. Five fitting protrusions 14, 15, 16, 17, 18 are formed on the inner surface of the side wall 8 along the center line extending in the longitudinal direction. 19, 20 and 21 are formed, and fitting protrusions 22 and 23 are formed on the end surfaces of the fitting protrusions 15 and 17, respectively. Further, a positioning projection 24 of the blade body 3 is formed on the inner surface of the front portion of the side wall 8. The positioning projection 24 extends in the longitudinal direction, and blade body fixing convex portions 25 and 26 are formed at both ends thereof. The blade body fixing convex portions 25, 26 are crushed to form a protruding portion 53 in the width direction as shown in FIG. 3 described for one blade body fixing convex portion 26, thereby forming the blade body 3. Is for permanently fixing. The blade body fixing convex portions 25, 26 are formed higher than the thickness of the blade body 3 because it is necessary to form a protruding portion 53 in the width direction and press and fix the blade body 3 with the protruding portion 53. ing. Further, the positioning projection 24 extending between the blade fixing convex portions 25 and 26 is formed lower than the blade fixing convex portions 25 and 26 and is formed to be equal to or slightly higher than the blade thickness 3. Is done.

  As shown in FIG. 6, the other half body 7 rises from the edge of the side wall 27 so that the upper wall 28, the lower wall 29, and the rear wall 30 of the half are continuous. The side wall 27 and the upper wall 28 and the lower wall 29 of the half are extended over substantially the entire length of the half body 7, whereby a groove 46 extending in the longitudinal direction is formed in the half body 7. A step surface 31 extends on the outer surfaces of the continuous upper wall 28, lower wall 29 and rear wall 30. The step surface 31 is not formed with a convex portion or a concave portion. Instead, on the edge surfaces of the continuous upper wall 28, lower wall 29 and rear wall 30, fitting protrusions at positions corresponding to the fitting recesses 13 formed in the step surface 12 of one half 6. 32 is formed. Five fitting projections 33, 34, 35, 36, and 37 are formed on the inner surface of the side wall 27 along a center line extending in the longitudinal direction. Portions 38, 39, and 40 are formed and fitted into the fitting holes 19, 20, and 21 of one half 6 during assembly. In addition, fitting holes 41 and 42 are formed in the end faces of the fitting protrusions 34 and 36, and are fitted to the fitting protrusions 22 and 23 of one half body 6 during assembly. Further, a positioning projection 43 of the blade body 3 is formed on the inner surface of the front portion of the side wall 27. Since the configuration of the positioning projection 43 is the same as that of the one positioning projection 24, description thereof is omitted.

  Next, the manufacturing method of the half body 6 with the blade body 3 fixed will be described taking one half body 6 as an example. The halved body 6 is formed by injection molding into the shape shown in FIG. 5 using a thermoplastic resin such as polycarbonate resin. Next, as shown in FIG. 7, after positioning the blade body 3 by fitting the positioning protrusion 24 into the long hole 44 of the blade body 3, the blade body fixing convex portion protruding from the blade body 3. By pressing and crushing 25 and 26, a protruding portion in the width direction is formed as shown in FIG. 8, and the blade body 3 is pressed and fixed by the protruding portion. Therefore, FIG. 8 shows a state in which the blade body 3 is permanently fixed to the half body 6. The blade body 3 is also permanently fixed to the other half body 7 by the same process.

  After the halves 6 and 7 in which the blade bodies 3 are permanently fixed are manufactured, the handles 2 are manufactured by combining them. Therefore, the halves 6 and 7 can be said to be handle parts constituting the handle 2. Next, a method for joining the halves 6 and 7 will be described. Since this invention is a medical device, both are couple | bonded by various fitting structures, without using an adhesive agent for coupling | bonding. Therefore, as described above, five fitting protrusions 14, 15, 16, 17, 18 are formed on the inner surface of the side wall 8 of one half 6 along the center line extending in the longitudinal direction. Fitting holes 19, 20, 21 are formed on the end faces of 14, 16, 18, and fitting convex parts 22, 23 are formed on the end faces of the fitting protrusions 15, 17. And the five fitting protrusions 33, 34, 35, 36, and 37 are formed in the inner surface of the side wall 27 of the other half body 7 along the centerline extended in a longitudinal direction, and the fitting protrusions 33, 35, and 37 are formed. Fitting projections 38, 39, 40 are formed on the end face of the halves, and are fitted into the fitting holes 19, 20, 21 of one half 6 when the two halves 6, 7 are joined. Furthermore, fitting holes 41 and 42 are formed in the end surfaces of the fitting protrusions 34 and 36, and are fitted to the fitting convex portions 22 and 23 of one half body 6 when coupled. In this fitting structure, the center portion of the handle 2 can be securely coupled, but the joints of the halves 6 and 7 are insufficiently coupled, and therefore another coupling structure is provided for this purpose. As described above, a predetermined number of fitting recesses 13 are formed at predetermined positions on the step surface 12 of one half 6. In addition, on the edge surfaces of the upper wall 28, the lower wall 29, and the rear wall 30 of the other half body 7, the positions corresponding to the fitting recesses 13 formed in the step surface 12 of the other half body 6. A fitting protrusion 32 is formed on the surface. Therefore, when the halves 6 and 7 are joined, the fitting recess 13 and the fitting protrusion 32 are fitted to each other to align the positions, and the fitting recess 13 and the fitting protrusion 32 are welded by ultrasonic welding. The joints of the halves 6 and 7 are securely connected.

  By joining both halves 6, 7, the handle 2 is completed, and the side wall 8 of one half 6, the upper wall 9 and the lower wall 10 of the half, and the side wall 27 of the other half 7. The peripheral wall 47 that surrounds the blade bodies 3 and 3 is formed at the front portion of the handle 2 by the upper wall 28 and the lower wall 29 of the half. As shown in FIG. 4, a cavity 52 is formed by the peripheral wall 47. As shown in FIG. 1, the outer shape of the handle 2 is formed symmetrically with respect to a center line extending in the longitudinal direction in a side view of the handle 2, and the front end portion of the handle 2 has a triangular shape. Since the hypotenuse 54 on the lower side of the triangle is formed in a straight line, the hypotenuse 54 slides on the skin etc. depending on the cutting depth when the tendon is cut and acts as a guide.

Next, the size of this embodiment will be described. The overall length of the handle 2 is about 135 mm, the maximum vertical width is about 13 mm, and the maximum lateral width is about 17 mm. The total length of the blade body 3 is about 45 mm, and the length of the blade edge 49 of the blade body 3 projected on a straight line in the longitudinal direction is about 28 mm. The distance between the blades 3, 3 extending in parallel is about 8 mm. A part of the upper edge and the lower edge of the blade bodies 3 and 3 are covered from above and below by the upper wall 50 and the lower wall 51 of the peripheral wall 47, but as shown in FIG. The edge 48 of the upper wall 50 of the peripheral wall 47 to be formed is in a straight line and covers the blade bodies 3 and 3 from above. The lower wall 51 of the peripheral wall 47 has the same length as the upper wall 50 and covers the blade bodies 3 and 3 from below. Further, the lower wall 51 reaches the position of the blade edge 49 of the blade body 3 and covers a part of the blade edge 49. The length in which the upper wall 50 and the lower wall 51 of the peripheral wall 47 cover the blade bodies 3 and 3 is about 30 mm. Therefore, the upper wall 50 and the lower wall 51 of the peripheral wall 47 cover approximately 67% of the entire length of the blade body 3 from the rear end of the blade body 3. For this reason, as shown in FIG. 8, the positions of the finger placement concave surfaces 4, 5 overlap with a substantially central portion of the blade body 3. Further, since the length in the longitudinal direction of the portion of the blade body 3 where the blade edge 49 is not formed is about 17 mm, the lower wall 51 of the peripheral wall 47 is a portion having a length of about 13 mm which is a length obtained by projecting the blade edge 49 onto the straight line in the longitudinal direction. Covering. That is, the blade edge 49 of the blade body 3 is covered with the lower wall 51 at 46% of the length projected on the straight line in the longitudinal direction. The size and the like are as described above, but the present invention is of course not limited to these numerical values.

The present invention can take various aspects and numerical values based on the above-described configuration. For example, all of the upper wall 50, the lower wall 51, and the pair of side walls 8, 27 of the peripheral wall 47 only need to cover 40% or more of the entire length of the blade body from the rear end of the attached blade body 3. However, it may be 50% or more or 60% or more, and is preferably about 67% ± 8% as in this embodiment. The halves 6 and 7 are not limited to the case where the seam passes through the center of the handle 2, and the seam may deviate from the center of the handle 2 within an allowable range. The cavity 52 may extend over the entire length of the handle 2 as in this embodiment, or may have a minimum length necessary for attaching the blade body 3. The method of fixing the blade body 3 is not limited to the method of crushing the blade body fixing convex portions 25 and 26. For example, when the halves 6 and 7 are molded, the blade bodies 3 are fixed to the side walls 8 and 27 by insert molding. It may be fixed. The blade body 3 may be configured to be fixed detachably without being permanently fixed. In that case, the handle 2 may be sterilized to be reusable. Needless to say, the shape of the blade body 3 is not limited to that shown in FIG. The interval between the two blade bodies 3 and 3 is not limited to the above-mentioned 8 mm. For example, a different knife may be prepared for each 1 mm in the range of 5 to 15 mm. In that case, if the handle 2 has a different color for each interval between the blades 3 and 3, the interval between the knife blades 3 and 3 can be determined instantaneously. The halves 6 and 7 may be decomposable without being permanently bonded. A large number of small protrusions and grooves for preventing slipping may be provided on the surface of the handle 2.

The blade of the replaceable blade type single-blade medical knife is used for the two-blade medical knife of the present invention by protruding the blade body from the opening of the cavity with a part of the blade edge covered by the lower wall. In this case, the replacement blade of the single-blade medical knife having a blade edge longer than necessary for the double-blade medical knife can be used as a blade having a length suitable for the double-blade medical knife. it can.

  DESCRIPTION OF SYMBOLS 1 Knife, 2 Handle, 3 Blade body, 4 Finger rest concave surface, 5 Finger rest concave surface, 6 One half split, 7 The other half split, 8 Side wall, 9 Upper wall, 10 Lower wall, 11 Rear wall, 12 Stepped surface, 13 Fitting recess, 14 Fitting projection, 15 Fitting projection, 16 Fitting projection, 17 Fitting projection, 18 Fitting projection, 19 Fitting hole, 20 Fitting hole, 21 Fitting hole, 22 Fitting Joint convex part, 23 Fitting convex part, 24 Positioning projection part, 25 Blade body fixing convex part, 26 Blade body fixing convex part, 27 Side wall, 28 Upper wall, 29 Lower wall, 30 Rear wall, 31 Step surface 32 fitting protrusions, 33 fitting protrusions, 34 fitting protrusions, 35 fitting protrusions, 36 fitting protrusions, 37 fitting protrusions, 38 fitting protrusions, 39 fitting protrusions, 4 Fitting convex part, 41 fitting hole, 42 fitting hole, 43 positioning protrusion, 44 long hole of blade body, 45 groove, 46 groove, 47 peripheral wall, 48 edge of upper wall, 49 cutting edge, 50 above peripheral wall Wall, 51 lower wall of peripheral wall, 52 cavity, 53 protruding part, 54 hypotenuse

Claims (8)

A medical knife in which two blades are attached in parallel to each other at the front part of the handle, and a cavity is formed in the front part of the handle, and the cavity is surrounded by a peripheral wall and has an opening in the front. The peripheral wall includes an upper wall, a lower wall, and a pair of opposing side walls, and the two blade bodies are respectively fixed to the inner surface of the side wall and project from the opening. . The medical knife according to claim 1, wherein all of the upper wall, the lower wall, and the pair of side walls of the peripheral wall cover a portion of 40% or more of the entire length of the blade body from the rear end of the attached blade body. The handle according to claim 1 or 2, wherein the handle is constituted by joining two halves, and each half is formed with one side wall and upper and lower walls of the half. Medical knife. Long holes are formed in the blade body, and convex portions that fit into the long holes are formed on the side walls to which the blade bodies are to be fixed, and the convex portions are formed higher than the thickness of the blade body. The blade body is fixed to the side wall by crushing and forming the protruding portion of the convex portion protruding from the long hole of the blade body to form a protruding portion in the width direction. The medical knife as described in any one. The medical knife according to any one of claims 1 to 4, wherein the outer shape of the handle is vertically symmetrical with respect to a center line extending in a longitudinal direction in a side view of the handle placed horizontally. 6. The medical knife according to claim 5, wherein finger placement concave surfaces are formed on the surface of the upper wall and the surface of the lower wall, and these finger placement concave surfaces overlap with a position of a part of the attached blade body. The medical knife according to claim 6, wherein the finger placement concave surface overlaps a position in the longitudinal center of the blade body or a position ahead thereof. A cavity is formed in the front part of the handle, the cavity is surrounded by a peripheral wall and has an opening in the front, and two blades are fixed to the inner surface of the peripheral wall so as to be parallel to each other with a space therebetween. A method of manufacturing a medical knife protruding from a front part, wherein two elongated handle parts having a peripheral wall constituting part constituting the peripheral wall are formed at a front part, and then formed at predetermined positions on the inner surface of each peripheral wall constituting part. A method of manufacturing a medical knife, characterized in that each blade body is fixed, and then both handle parts are joined so that each peripheral wall component cooperates to form a cavity.

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