Patent Publication Number: US-2016242629-A1

Title: Endoscope

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT/JP2014/074910 filed on Sep. 19, 2014 and claims benefit of Japanese Application No. 2014-055376 filed in Japan on Mar. 18, 2014, the entire contents of which are incorporated herein by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope including a bending lever for performing operation to bend a bending portion, at an operation portion. 
     2. Description of the Related Art 
     Endoscopes that enable, e.g., observation to be performed by inserting an elongated insertion portion into a subject have been in wide use. Some of these endoscopes are of a type in which a bending portion is provided on the distal end side of the insertion portion. The bending portion is generally configured so as to perform bending operation by a bending operation apparatus provided at the operation portion being operated to pull/loosen a bending wire. 
     For example, Japanese Patent Application Laid-Open Publication No. 2006-110053 indicates an electronic endoscope in which a grip portion for grasping is provided at an operation portion joined to a proximal end of an insertion portion. At one side face on the rear end side relative to the grip portion of the operation portion, a dial portion, which is a first operation member, and an operation lever, which is a second operation member, are provided as bending operation means for operating the bending portion. The provision of the two types of operation members as the bending operation means enables quick bending operation to be performed by operating the operation lever with a thumb alone and also enables fine bending operation to be performed by pinching the dial portion from opposite sides and operating the dial portion. 
     Japanese Patent Application Laid-Open Publication No. 2007-190047 indicates a body operation portion to be held by a surgeon with his/her hand to operate an endoscope. The body operation portion includes a casing, and the casing includes a body casing, a front casing and a rear casing. An insertion portion extends from the front casing, and a universal cord is drawn out from the rear casing. 
     A shaft end of a pulley drive shaft projects from each of opposite side portions of the body casing, an angle operation lever is provided at each of the shaft ends. Each angle operation lever extends in a direction perpendicular to the pulley drive shaft along a corresponding side face of the body casing. A distal end portion of each extending lever is flexed in a direction that is parallel to the pulley drive shaft, whereby a finger rest/operation portion to be operated with a finger of a hand is formed. It is described that when the front casing of the endoscope is grasped, the first finger is positioned on the finger rest/operation portion side, and when the rear casing is grasped, the thumb is positioned on the finger rest/operation portion side. 
     If a surgeon tries to insert the endoscope in Japanese Patent Application Laid-Open Publication No. 2006-110053 or Japanese Patent Application Laid-Open Publication No. 2007-190047 to, for example, a nasal cavity to conduct an examination, generally, the insertion portion is inserted to the nasal cavity of the patient, for example, sitting on a chair, with the insertion portion kept substantially horizontal. Thus, the operation portion provided in alignment with a longitudinal axis direction of the insertion portion is grasped as illustrated in  FIGS. 12(A) and 12(B)  in Japanese Patent Application Laid-Open Publication No. 2006-110053, and an operation knob is operated with the thumb. In this grasping and operation state, the surgeon needs to keep the insertion portion horizontal by tilting the wrist forward in a posture in which the armpit is spaced from the body side and the elbow is lifted. This posture for holding gives a large burden on the surgeon and may cause the insertion of the insertion portion to be unstable. 
     Here, in the case of the endoscope in Japanese Patent Application Laid-Open Publication No. 2007-190047, the insertion portion may be inserted into a nasal cavity with the front casing grasped and the first finger positioned on the finger rest/operation portion side. In this case, the surgeon has to twist the wrist in order to keep the insertion portion horizontal. This posture for holding also gives a large burden on the surgeon and may cause the bending operation of the bending portion and the insertion of the insertion portion to be unstable. 
     Japanese Patent Application Laid-Open Publication No. 2009-189684 indicates an endoscope in which an operation grasping portion is flexed, which is what is called “gun type”. In this endoscope, an operation lever for performing operation to bend a bending portion is configured so as to rotate while facing a rear face of the operation portion. In the case of the endoscope having this configuration, a surgeon can easily keep the insertion portion horizontal and insert the insertion portion to a nasal cavity with the operation grasping portion stably grasped without the wrist being twisted and also can smoothly operate the operation lever with the thumb of the hand grasping the operation grasping portion. 
     As illustrated in  FIG. 1 , even with an endoscope  100  including a gun-type operation portion  101 , a bending lever  102  can be operated with a first finger  112  of one hand  110  of a user by holding the operation portion  101  between a thumb  111  and a second finger  113 . 
     Reference numerals  103  and  104  each denote a push-button switch. The first switch  103  is arranged, for example, as a release switch for shooting an endoscopic image to be displayed on a display apparatus (not-illustrated), and the second switch  104  is arranged as a freeze switch for temporarily freezing an endoscopic image displayed on the display apparatus. Reference numeral  105  denotes an insertion portion of the endoscope  100 . 
     SUMMARY OF THE INVENTION 
     An endoscope according to an aspect of the present invention includes: an insertion portion including a bending portion that is bendable at least upward and downward on a distal end portion side; a cylindrical operation portion provided so as to be continuous with a proximal end side of the insertion portion, the operation portion having a first longitudinal axis substantially parallel to a longitudinal axis of the insertion portion and being capable of forming a part of a first grasping portion to be grasped by one hand of a user; a cylindrical extension portion provided so as to be continuous with a proximal end side of the operation portion, the extension portion having a second longitudinal axis extending in a downward bending direction of the bending portion and being capable of forming a part of the first grasping portion and a second grasping portion to be grasped by the one hand; and a bending lever which has a first end portion pivotally provided at the operation portion, and a second end portion provided so as to extend from the first end portion in an upward bending direction of the bending portion, a finger of the one hand grasping the first grasping portion or the second grasping portion being placed on the second end portion when operation to bend the bending portion is performed. 
     An endoscope according to an aspect of the present invention includes: an insertion portion including, on a distal end portion side, a bending portion that is bendable at least upward and downward; a cylindrical operation portion provided so as to be continuous with a proximal end side of the insertion portion, the operation portion having a first longitudinal axis substantially parallel to a longitudinal axis of the insertion portion and being capable of forming a part of a first grasping portion to be grasped by one hand of a user; a cylindrical extension portion provided so as to be continuous with a proximal end side of the operation portion, the extension portion being capable of forming a part of the first grasping portion and a second grasping portion to be grasped by the one hand; and a bending lever including a first end portion pivotally provided at the operation portion, and a second end portion provided so as to extend from the first end portion in an upward bending direction of the bending portion, where a finger of the one hand grasping the first grasping portion or the second grasping portion is placed on the second end portion when operation to bend the bending portion is performed, and the extension portion includes a first extension portion having a third longitudinal axis substantially parallel to the longitudinal axis of the insertion portion and a second extension portion provided so as to be continuous with a proximal end side of the first extension portion, the second extension portion having a second longitudinal axis extending in the downward bending direction of the bending portion and being inclined relative to the third longitudinal axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an example of a grasping state in an attempt to operate a bending lever provided at a conventional gun-type operation portion with a first finger; 
         FIG. 2  is a diagram for describing an endoscope according to the present invention, which is a view of one side of the endoscope; 
         FIG. 3  is a top view of the endoscope in  FIG. 2  as viewed in the arrow Y3 direction; 
         FIG. 4  is a front view of the endoscope in  FIG. 3  as viewed in the arrow Y4 direction; 
         FIG. 5  is a diagram illustrating a first grasping state of a grasping operation portion; 
         FIG. 6  is a diagram illustrating a second grasping state of the grasping operation portion; 
         FIG. 7  is a diagram illustrating a relationship between a shape of a hand and an extension portion in the second grasping state; 
         FIG. 8  is a diagram illustrating a modification of the second grasping state; 
         FIG. 9  is a diagram illustrating another configuration of the grasping operation portion; and 
         FIG. 10A  includes diagrams each illustrating a grasping state of the grasping operation portion including a flexed extension portion in  FIG. 9 . 
         FIG. 10B  includes diagrams each illustrating a grasping state of the grasping operation portion including a flexed extension portion in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the drawings. 
     As illustrated in  FIG. 2 , an endoscope  1  mainly includes an insertion portion  2 , a grasping operation portion  3  and a universal cable  4 . The grasping operation portion  3  includes an operation portion  5  and an extension portion  6  integrally and fixedly provided. At the operation portion  5 , a bending lever  7  is provided. 
     The insertion portion  2  is inserted to, for example, a nasal cavity. 
     In the insertion portion  2 , a distal end portion  2   a , a bending portion  2   b  and a flexible tube portion  2   c  are provided so as to be continuous in this order from the distal end side. Inside the distal end portion  2   a , an image pickup apparatus (not-illustrated) including an image pickup device such as a CCD or C-MOS that picks up an image of a subject part is incorporated. Also, an image pickup apparatus including an image guide fiber instead of the image pickup device may be employed. 
     The bending portion  2   b  is configured so as to bend, for example, upward and downward. The bending portion  2   b  bends along with operation of the bending lever  7 . The distal end portion  2   a  moves in an upward bending direction, which is indicated by arrow Yu in the figure, as a result of the bending portion  2   b  bending upward, and moves in a downward bending direction, which is indicated by arrow Yd, as a result of the bending portion  2   b  bending downward. 
     The flexible tube portion  2   c  has a flexibility that enables the flexible tube portion  2   c  to deform along a nasal cavity in a state in which the insertion portion  2  is inserted in the nasal cavity. 
     The operation portion  5  is provided so as to be continuous with the proximal end side of the insertion portion  2 . 
     The bending lever  7  is provided on the extension portion  6  side of the operation portion  5 , which is a proximal end portion of the operation portion  5 . 
     As illustrated in  FIGS. 2 to 4 , the bending lever  7  is provided with a lever body  7   a  and a finger rest  7   b  and has a substantially L-shape. 
     The lever body  7   a  includes a first end and a second end. The first end portion  7   c  is disposed on the one side face  5   a  side of the operation portion  5  so as to be pivotable via a pivot shaft member  7   d . As illustrated in  FIG. 3 , a pivot axis  7   da  is substantially perpendicular to a first longitudinal axis A 1 . 
     The lever body  7   a  is provided so as to extend along the one side face  5   a  from the pivot shaft member  7   d  in the upward bending direction, and at the second end portion  7   e , which is an end portion of the extension, a finger rest  7   b  is fixedly provided. The finger rest  7   b  includes a finger placing surface  7   f . The finger placing surface  7   f  is provided with a slip stopper including, for example, recess and projection portions. The finger placing surface  7   f  of the finger rest  7   b  is provided a predetermined distance away from an upper face  5   u  of the operation portion  5 . 
     The upper face  5   u  is a surface on the upward bending direction side of the bending portion  2   b , and a surface opposite to the upper face  5   u  is a lower face  5   d  on the downward bending direction side. 
     The lever body  7   a  of the bending lever  7  configured as described above pivots about the pivot shaft member  7   d  as indicated in arrow Ycw and arrow Yccw along the upper face  5   u  of the operation portion  5 . Therefore, a surface in the upper face  5   u , the surface corresponding to a lever movement range, includes a curved surface. 
     The bending portion  2   b  is configured so as to bend, for example, upward upon the bending lever  7  being moved in the arrow Yccw direction, and bends downward, which is the opposite direction, upon the bending lever  7  being moved in the arrow Yew direction. 
     Here, in the present embodiment, the lever body  7   a  is provided on the one side face  5   a  side of the operation portion  5 . However, the lever body  7   a  may be provided on the other side face  5   b  side, which is a surface on the opposite side of the one side face  5   a  of the operation portion  5 . 
     Also, the bending portion  2   b  may be configured so as to bend upward upon the bending lever  7  being moved in the arrow Ycw direction, and bend downward upon the bending lever  7  being moved in the arrow Yccw direction. 
     Furthermore, if the bending portion  2   b  is configured so as to bend upward, downward, rightward and leftward, a lever body for upward and downward bending or a lever body for rightward and leftward bending is provided at the one side face  5   a  of the operation portion  5 , and a lever body that is different from the lever body provided at the one side face  5   a  is provided at the other side face  5   b.    
     Also, the bending lever  7  may be configured in a rod-like joystick form. In this configuration, the rod portion of the joystick is provided so as to extend in the upward bending direction from the upper face  5   u . A first end portion of the rod portion is pivotally provided inside the operation portion, and at a second end portion of the rod-like portion, for example, a spherical finger rest is provided. 
     Here, a configuration of each of the operation portion  5  and the extension portion  6  will be described with reference to  FIGS. 2 to 4 . 
     First, the configuration of the operation portion  5  will be described. 
     The operation portion  5  illustrated in  FIGS. 2 to 4  is a hollow cylindrical member, and has a first longitudinal axis A 1 , which is an axis in a longitudinal direction parallel to a longitudinal axis Aa of the insertion portion  2 . In the present embodiment, the longitudinal axis Aa and the first longitudinal axis A 1  are coaxial to each other. 
     Note that a positional relationship between the longitudinal axis Aa and the first longitudinal axis A 1  is not limited to the coaxial relationship and it is only necessary that the longitudinal axis Aa and the first longitudinal axis A 1  be in substantially-parallel relationship. 
     The operation portion  5  includes a distal end face, the upper face  5   u , the lower face  5   d , a projection portion  5   c , the one side face  5   a  and the other side face  5   b , and a proximal end face. The distal end face is a surface perpendicular to the first longitudinal axis A 1 , and the insertion portion  2  extends from the distal end face. The upper face  5   u  is a surface that the finger rest  7   b  faces. The projection portion  5   c  projects from the lower face  5   d . The one side face  5   a  is a surface at which the lever body  7   a  is disposed. The proximal end face is a surface to which a distal end face of the extension portion  6  is integrally fixed. 
     In the operation portion  5  in the present embodiment, an area  5   h , which is indicated by the dashed line in  FIG. 2 , and a proximal end face  5   ch  of the projection portion  5   c  are configured so as to be capable of forming a part of a first grasping portion  5 H to be grasped in a first grasping state. The area  5   h  is provided on each of the one side face  5   a  side and the other side face  5   b  side. 
     More specifically, the projection-portion proximal end face  5   ch  is an abutment surface. In the first grasping state illustrated in  FIG. 5 , for example, a base part between a thumb  51  and a first finger  52 , or the palm of a right hand  50 , which is one hand, are in abutment with the projection-portion proximal end face  5   ch , whereby the position of the hand in the first grasping state is defined. 
     The area  5   h  in the one side face  5   a  is a first-grasping-portion first forming surface  5   ah . In the first grasping state in  FIG. 5 , a ball part of the thumb  51  of the right hand is placed on the first-grasping-portion first forming surface  5   ah . The area  5   h  in the other side face  5   b  is a first-grasping-portion second forming surface  5   bh . In the first grasping state, a side portion on the first finger side of a second finger  53  of the right hand is placed on the first-grasping-portion second forming surface  5   bh.    
     Here, when the surgeon grasps the operation portion  5  with his/her left hand, a side portion on the first finger side of the second finger of the left hand is placed on the first-grasping-portion first forming surface  5   ah , a ball-side part of the thumb of the left hand is placed on the first-grasping-portion second forming surface  5   bh , and thus the first-grasping-portion first forming surface  5   ah  and the first-grasping-portion second forming surface  5   bh  can form a part of the first grasping portion  5 H to be grasped in the first grasping state. 
     In the present embodiment, push-button switches  9   c  and  9   d  are provided at respective predetermined positions in the upper face  5   u , and push-button switches  9   a  and  9   b  are provided at respective predetermined positions in the projection portion distal end face  5   f  of the projection portion  5   c.    
     The first switch  9   a  and the second switch  9   b  are arranged vertically symmetrically relative to a vertical axis Va in  FIG. 4 . Also, the third switch  9   c  and the fourth switch  9   d  are arranged also vertically symmetrically relative to the vertical axis Va. The switches  9   c  and  9   d  are arranged so as to be positioned in the upward bending direction relative to a position at which a proximal end portion of the insertion portion  2  is disposed. 
     In the present embodiment, the first switch  9   a  and the third switch  9   c  are provided as, for example, release switches for shooting an endoscopic image to be displayed on a display apparatus (not-illustrated). The second switch  9   b  and the fourth switch  9   d  are provided as, for example, freeze switches for temporarily freezing an endoscopic image displayed on the display apparatus. 
     Reference numeral  8 A denotes a first bend preventing member. The first bend preventing member  8 A covers an outer periphery of the flexible tube portion  2   c  joined to the operation portion  5  and prevents the flexible tube portion  2   c  from buckling. 
     Next, as a configuration of the extension portion  6  will be described. 
     The extension portion  6  illustrated in  FIGS. 2 to 4  is a hollow cylindrical member as with the operation portion  5 . The extension portion  6  has a second longitudinal axis A 2  that is different from the first longitudinal axis A 1  in that the second longitudinal axis A 2  is not parallel to the longitudinal axis Aa. In the present embodiment, the second longitudinal axis A 2  is a circular arc-shape axis extending from the first longitudinal axis A 1  in the downward bending direction of the bending portion  2   b.    
     Thus, a proximal end face of the extension portion  6  is positioned in the downward bending direction of the bending portion  2   b  relative to the first longitudinal axis A 1 . The universal cable  4  extends from the proximal end face. As described above, the distal end face of the extension portion  6  is integrally fixed to the proximal end face of the operation portion  5 . 
     Here, in  FIG. 3 , the first longitudinal axis A 1  and the second longitudinal axis A 2  are arranged in alignment with each other. However, the relevant configuration in the present invention is not limited to the configuration in which the first longitudinal axis A 1  and the second longitudinal axis A 2  are arranged in alignment with each other, and there may be a position gap between the first longitudinal axis A 1  and the second longitudinal axis A 2  while the first longitudinal axis A 1  and the second longitudinal axis A 2  are parallel to each other. 
     The extension portion  6  in the present embodiment includes the distal end face, an inner external surface  6   i , an outer external surface  6   o , one side face  6   a , the other side face  6   b  and the proximal end face. The inner external surface  6   i , which is a circular arc surface, is a surface forming a part on the center O 2  side relative to the second longitudinal axis A 2 . The outer external surface  6   o , which is a circular arc surface, is a surface forming a part on the outer side relative to the second longitudinal axis A 2 . The one side face  6   a  is a surface connecting the inner external surface  6   i  and the outer external surface  6   o . The other side face  6   b , which is a surface opposite to the one side face  6   a , is a surface connecting the inner external surface  6   i  and the outer external surface  6   o.    
     The extension portion  6  in the present embodiment is configured so as to be capable of forming a second grasping portion  6 H to be grasped, for example, by a right hand  50  of one hand in a second grasping state as illustrated in  FIG. 6 , and forming a part of the first grasping portion  5 H to be grasped in the first grasping state illustrated in  FIG. 5 . 
     As illustrated in  FIG. 2 , the second grasping portion  6 H is formed by the one side face  6   a , the other side face  6   b , the inner external surface  6   i  and the outer external surface  6   o . In the second grasping state illustrated in  FIG. 6 , the second grasping portion  6 H is grasped by a thenar  57 , a palm  56  and, for example, three fingers that are a fourth finger  55 , a third finger  54  and a second finger  53  of a surgeon. Thus, a length in an axial direction of the second grasping portion  6 H is set as a predetermined dimension in consideration of a width dimension of the palm  56 . 
     In the second grasping state, the thenar  57  of the surgeon is placed on the outer external surface  6   o , the palm  56  of the surgeon is placed on the other side face  6   b , a ball part of a tip of the fourth finger  55 , a ball part of a tip of the third finger  54  and a ball part of a tip of the second finger  53  of the surgeon are placed on the one side face  6   a , a ball-side part between a first joint and a second joint of the fourth finger  55 , a ball-side part between a first joint and a second joint of the third finger  54  and a ball-side part between a first joint and a second joint of the second finger  53  of the surgeon are placed on the inner external surface  6   i.    
     In the present embodiment, an inner diameter R of the inner external surface  6   i  of the extension portion  6  is set to be no less than 60 mm and no more than 90 mm. The dimension of the inner diameter R ensures a stable second grasping state. The inner diameter R is a value obtained based on a line L connecting a point  53   p  on a part of the inner external surface  6   i  of the extension portion  6  corresponding to a part between the first joint and the second joint of the second finger  53 , a point  54   p  on a part of the inner external surface  6   i , the part corresponding to a part between the first joint and the second joint of the third finger  54 , and a point  55   p  on a part of the inner external surface  6   i , the part corresponding to a part between the first joint and the second joint of the fourth finger  55  in a state in which the palm of the hand is lightly clenched as illustrated in  FIG. 7 . 
     Here, an outer diameter of the outer external surface  6   o  is a value obtained based on a shell structure S formed by the thenar  57  and a hypothenar  58  in the state in which the palm of the hand is slightly clenched as illustrated in  FIG. 7 . The outer diameter of the outer external surface  6   o  is set to be no less than 100 mm and no more than 120 mm. 
     As described above, as a result of the inner diameter of the inner external surface  6   i  and the outer diameter of the outer external surface  6   o , the inner external surface  6   i  and the outer external surface  6   o  being included in the extension portion  6 , being set, an area of the palm of the hand, the area being in contact with the second grasping portion  6 H, in the second grasping state increases, enabling provision of reliable and conformable grasping. 
     Here, if the surgeon grasps the extension portion  6  with his/her left hand, a thenar  57  may be placed on the outer external surface  6   o , a palm  56  may be placed on the one side face  6   a , a ball part of a tip of a fourth finger  55 , a ball part of a tip of a third finger  54  and a ball part of a tip of a second finger  53  may be placed on the other side face  6   b , a ball-side part between a first joint and a second joint of the fourth finger  55 , a ball-side part between a first joint and a second joint of the third finger  54  and a ball-side part between a first joint and a second joint of the second finger  53  may be placed on the inner external surface  6   i.    
     On the other hand, in the first grasping state illustrated in  FIG. 5 , a base part between the thumb  51  and the first finger  52  of the right hand of the surgeon is placed on the inner external surface  6   i  of the extension portion  6 . In other words, an operation portion-side end face  6   ib  is a first-grasping-portion third forming surface. Therefore, the first grasping portion  5 H is formed by the first-grasping-portion first forming surface  5   ah , the first-grasping-portion second forming surface  5   bh , the projection-portion proximal end face  5   ch  and the operation portion-side end face  6   ib.    
     Here, reference numeral  8 B denotes a second bend preventing member. The second bend preventing member  8 B covers an outer periphery of the universal cable  4  connected to the extension portion  6  and prevents, for example, a signal cable inserted inside the universal cable  4 , the signal cable being connected to an image pickup section, from being flexed sharply. Also, the second bend preventing member  8 B may be used as a part of a grasping portion to be grasped by a surgeon with large hands. 
     Operation of the endoscope  1  configured as described above will be described. 
     The endoscope  1  according to the present embodiment is configured so that the grasping operation portion  3  can be grasped in the above-described first grasping state and can also be grasped in the second grasping state. 
     Therefore, if a surgeon wishes to operate the bending lever  7  with, for example, his/her first finger, as illustrated in  FIG. 5 , the grasping operation portion  3  of the endoscope  1  may be grasped in the first grasping state. 
     On the other hand, if the surgeon wishes to operate the bending lever  7  with, for example, his/her thumb, as illustrated in  FIG. 6 , the grasping operation portion  3  of the endoscope  1  may be grasped in the second grasping state. 
     When the first grasping state illustrated in  FIG. 5  is selected, the surgeon grasps the first grasping portion  5 H. In other words, with the palm part between the thumb  51  and the first finger  52  of the right hand  50  in abutment with the projection-portion proximal end face  5   ch , the surgeon places the ball-side part of the thumb  51  on the first-grasping-portion first forming surface  5   ah , and places the side portion on the first-finger side of the second finger  53  on the first-grasping-portion second forming surface  5   bh . Then, the surgeon places the base part between the thumb  51  and the first finger  52  of the right hand on the operation portion-side end face  6   ib  and adjusts the position of the base part. 
     As a result, the surgeon can grasp the grasping operation portion  3  with the right hand  50  in the first grasping state. In the first grasping state, the surgeon performs operation to pivot the bending lever  7  with a ball part of a tip of the first finger  52  on the finger placing surface  7   f  of the finger rest  7   b . Here, the surgeon can perform fine lever operation by bending or extending the third joint, the second joint and the first joint of the first finger  52 . 
     When the second grasping state illustrated in  FIG. 6  is selected, the surgeon grasps the second grasping portion  6 H. In other words, the surgeon grasps the second grasping portion  6 H so as to grip the second grasping portion  6 H lightly with the palm  56  and the fingers  53 ,  54  and  55  other than the first finger  52  of the right hand  50 . Then, a ball portion between the first joint and the second joint of the second finger  53 , a ball portion between the first joint and the second joint of the third finger  54  and a ball portion between the first joint and the second joint of the fourth finger  55  are placed in close contact on the inner external surface  6   i  included in the extension portion  6 , and the thenar  57  and the hypothenar  58  are placed in close contact on the outer external surface  6   o.    
     As a result, the surgeon can grasp the grasping operation portion  3  with his/her right hand  50  in the second grasping state. In the second grasping state, the surgeon performs operation to pivot the bending lever  7  with the ball portion of the tip of the thumb  51  placed on the finger placing surface  7   f  of the finger rest  7   b . Here, the surgeon can perform stable lever operation by bending or extending the second joint and the first joint of the thumb  51 . 
     As described above, the grasping operation portion  3  is configured by integrally joining the operation portion  5  and the extension portion  6  to each other. Here, the proximal end face of the extension portion  6  is positioned in the downward bending direction of the bending portion  2   b  relative to the first longitudinal axis A 1  of the operation portion  5 , and the second longitudinal axis A 2  of the extension portion  6  is set so as to have a circular arc shape. 
     As a result, the first grasping portion  5 H that enables the bending lever  7  to be operated with the first finger and the second grasping portion  6 H that enables the bending lever  7  to be operated by the thumb are provided in the grasping operation portion  3 . The first grasping portion  5 H is formed by the first-grasping-portion first forming surface  5   ah , the first-grasping-portion second forming surface  5   bh , the projection-portion proximal end face  5   ch  and the operation portion-side end face  6   ib , and the second grasping portion  6 H is formed by the one side face  6   a , the other side face  6   b , the inner external surface  6   i  and the outer external surface  6   o.    
     Therefore, the surgeon can select a grasping state for grasping the grasping operation portion  3  according to usage of the endoscope  1  or the surgeon&#39;s preference and thereby operate the bending lever  7  with his/her thumb or first finger. 
     Also, the push-button third switch  9   c  and fourth switch  9   d  are provided vertically symmetrically relative to the vertical axis Va at the respective predetermined positions in the upper face  5   u , and the push-button first switch  9   a  and second switch  9   b  are provided vertically symmetrically relative to the vertical axis Va at the respective predetermined positions in the projection portion distal end face  5   f  of the projection portion  5   c . Then, a same function is assigned to the first switch  9   a  and the third switch  9   c , and a function that is different from the function of the first switch  9   a  and the third switch  9   c  is provided to the second switch  9   b  and the fourth switch  9   d  or a function that is different from those of the others is provided to each of all of the switches from the first switch  9   a  to the fourth switch  9   d . Consequently, irrespective of the first grasping state or the second grasping state, and also irrespective of the left hand or the right hand being used for grasping, lever operation and push-button operation of the switches can smoothly be performed. 
     Note that, according to the endoscope including the grasping operation portion  3  configured as described above, a second grasping state can be provided by grasping the second grasping portion  6 H of the extension portion  6  with a thenar  57 , a palm  56 , two fingers that are a third finger  54  and a fourth finger  55  as illustrated in  FIG. 8 . In this second grasping state, lever operation can be performed by a thumb  51  and push-button operation of the switches can be performed by a first finger  52  or a second finger  53 . Also, in the above-described embodiment, in order to position the proximal end face of the extension portion  6  whose distal end face is integrally fixed to the proximal end face of the operation portion  5  in the downward bending direction of the bending portion  2   b  relative to the first longitudinal axis A 1  of the operation portion  5 , the second longitudinal axis A 2  of the extension portion  6  is formed in a circular arc shape, enabling a grasping state for grasping the grasping operation portion  3  to be selected according to the usage of the endoscope  1  or the surgeon&#39;s preference, thus enabling bending lever  7  to be operated with the thumb or the first finger. 
     However, as illustrated in  FIG. 9 , operation and effects that are similar to those of the above-described embodiment may be obtained by providing a grasping operation portion  3 A. Note that, in the below description, members that are the same as those of the above-described embodiment are provided with reference numerals that are the same as those of the embodiment and description thereof will be omitted. 
     A grasping operation portion  3 A according to the present embodiment includes an operation portion  5  and an extension portion  6 A. The extension portion  6 A includes a first extension portion  61  and a second extension portion  62  integrally and fixedly provided. 
     Each of the first extension portion  61  and the second extension portion  62  is a hollow cylindrical member as with the operation portion  5 . Each of a longitudinal axis of the first extension portion  61  and a longitudinal axis of the second extension portion  62  is a linear axis. 
     The first extension portion  61  has a third longitudinal axis A 3 , which is an axis in a longitudinal direction substantially parallel to a longitudinal axis Aa as with a first longitudinal axis A 1 . A length in the longitudinal direction of the first extension portion  61  is set to be no less than 20 mm and no more than 40 mm. 
     In the present embodiment, the longitudinal axis Aa and the third longitudinal axis A 3  are arranged substantially in parallel to each other, and may have a position gap therebetween as illustrated in the figure or may be coaxial to each other as described above. 
     The second extension portion  62  has a second longitudinal axis A 2   a , which is inclined relative to the longitudinal axis A 3 . The second longitudinal axis A 2   a  is a linear or circular arc axis. The second longitudinal axis A 2   a  extends from the third longitudinal axis A 3  side in the downward bending direction of the bending portion  2   b . A proximal end face of the first extension portion  61  and a distal end face of the second extension portion  62  are smoothly connected with a flexed portion  63  provided therebetween. In other words, the extension portion  6 A is configured as a flexed extension portion as a result of the inclusion of the first extension portion  61  and the second extension portion  62 . 
     Therefore, a proximal end face of the second extension portion  62 , which is a proximal end face of the extension portion  6 A, is positioned in the downward bending direction of the bending portion  2   b  relative to the third longitudinal axis A 3 . A universal cable  4  extends from the proximal end face. 
     The extension portion  6 A in the present embodiment is configured so as to be capable of forming a second grasping portion  6 HA to be grasped in a second grasping state, and a part of a first grasping portion  5 HA to be grasped in a first grasping state. 
     In the present embodiment, the second grasping portion  6 HA includes a flexed-extension-portion other side face  65 , a flexed-extension-portion outer face  66 , a flexed-extension-portion inner surface  66 , a flexed-extension-portion one side face  67  of the extension portion  6 A. 
     As illustrated in  FIG. 10A , in the second grasping state, a surgeon grasps the grasping operation portion  3 A with a thenar  57 , a palm  56  and, for example, three fingers that are a fourth finger  55 , a third finger  54  and a second finger  53 . In other words, in the second grasping state, the surgeon places the thenar  57  on the flexed-extension-portion outer face  64 , places the palm  56  on the flexed-extension-portion other side face  65 , places respective ball parts of the second finger  53 , the third finger  54  and the fourth finger  55  on the flexed-extension-portion inner surface  66 , and places respective tip portions of the second finger  53 , the third finger  54  and the fourth finger  55  on the flexed-extension-portion one side face  67 . 
     Here, if the surgeon grasps the extension portion  6 A with his/her left hand, the surgeon places a thenar  57  on the flexed-extension-portion outer face  64 , places a palm  56  on the flexed-extension-portion one side face  67 , place respective ball portions of a second finger  53 , a third finger  54  and a fourth finger  55  on the flexed-extension-portion inner surface  66 , and places respective tip parts of the second finger  53 , the third finger  54  and the fourth finger  55  on the flexed-extension-portion other side face  65 . 
     On the other hand, in the present embodiment, the first grasping portion  5 HA is formed by a first-grasping-portion first forming surface  5   ah , a first-grasping-portion second forming surface  5   bh  and a projection-portion proximal end face  5   ch  of the operation portion  5  and an operation portion-side face  66   b  of the flexed-extension-portion inner surface  66  of the extension portion  6 A. 
     As illustrated in  FIG. 10B , in the first grasping state, the surgeon place a base part between a thumb  51  and a first finger  52  of his/her right hand on the operation portion-side face  66   b  of the flexed-extension-portion inner surface  66 . In other words, in the present embodiment, the operation portion-side face  66   b  of the flexed-extension-portion inner surface  66  is a first-grasping-portion third forming surface whose length in a longitudinal direction is set to be no less than 20 mm and no more than 40 mm. 
     In other words, in the first grasping state, with the base part between the thumb  51  and the first finger  52  placed on the operation portion-side face  66   b , the surgeon places a ball-side part of the thumb  51  on the first-grasping-portion first forming surface  5   ah , and places a side portion on the first finger side of the second finger  53  on the first-grasping-portion second forming surface  5   bh.    
     Here, if the surgeon grasps the extension portion  6 A with his/her left hand, with a base part between a thumb  51  and a first finger  52  placed on the operation portion-side face  66   b , the surgeon places a ball-side part of the thumb  51  on the first-grasping-portion second forming surface  5   bh , and places a side part on the first finger side of a second finger  53  on the first-grasping-portion first forming surface  5   ah.    
     As described above, when the grasping operation portion  3 A is formed by integrally joining the operation portion  5  and the extension portion  6 A, the extension portion  6 A is formed as a flexed extension portion. As a result, the first grasping portion  5 HA that enables the bending lever  7  to be operated with a first finger and the second grasping portion  6 HA that enables the bending lever  7  to be operated with a thumb can be provided in the grasping operation portion  3 A. 
     Therefore, as in the above-described embodiment, the surgeon can select a grasping state for grasping the grasping operation portion  3 A according to usage of the endoscope  1  or the surgeon&#39;s preference and operate the bending lever  7  with the thumb or the first finger. 
     The present invention is not limited only to the above-described embodiments and various modifications are possible without departing from the spirit of the invention.