Patent Publication Number: US-2018028052-A1

Title: Endoscope system

Description:
FIELD OF THE INVENTION 
     Embodiments described herein relate generally to an endoscope system capable of visually recognizing the inside of a cavity of a subject. 
     DESCRIPTION OF THE RELATED ART 
     For example, Japanese Patent Application Publication No. 5-15484 discloses an endoscope capable of quantitatively recognizing an angle of a distal end portion of an inserting tube in the body cavity of the subject from outside of the subject. 
     BRIEF SUMMARY OF THE INVENTION 
     An endoscope comprises, a holding unit, a guide pipe extending from the holding unit, an endoscope including a distal end portion capable of acquiring an image, the endoscope being inserted through an inside of the guide pipe and bendable in at least one plane, a bending operation unit rotatably provided on the holding unit and capable of adjusting a bending angle of the endoscope; and a pointer provided on the bending operation unit and indicating an extending direction of the distal end portion in the plane. 
     Advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a schematic diagram illustrating a whole structure of an endoscope system according to an embodiment, and illustrating an inside of a guide pipe by cutting the guide pipe; 
         FIG. 2  is a schematic diagram illustrating an inside of a holding unit of the endoscope system illustrated in  FIG. 1  that is cut along line F 2 -F 2 ; 
         FIG. 3  is a schematic diagram schematically illustrating a distal end portion and therearound of an endoscope inserting unit of the endoscope system illustrated in  FIG. 1 ; 
         FIG. 4  is a schematic diagram schematically illustrating that an extending direction of the distal end portion agrees with an indicating direction of a pointer, when a dial portion of a bending operation unit is rotated to bend a flexible tube of the endoscope inserting unit, in the endoscope system illustrated in  FIG. 1 ; 
         FIG. 5  is a schematic diagram illustrating a whole structure of an endoscope system according to a first modification, and illustrating an inside of a guide pipe by cutting the guide pipe; 
         FIG. 6  is a schematic diagram illustrating a whole structure of an endoscope system according to a second modification, and illustrating an inside of a guide pipe by cutting the guide pipe; and 
         FIG. 7  is a schematic diagram schematically illustrating that an extending direction of a distal end portion agrees with an indicating direction of a second pointer of a second dial portion, in a state where the distal end portion of an endoscope inserting unit is caused to widely project from the guide pipe, in the endoscope system illustrated in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment will be explained hereinafter with reference to  FIG. 1  to  FIG. 4 . 
     As illustrated in  FIG. 1 , an endoscope system  11  according to the present embodiment includes an inserting device  12  that is inserted to be used into a cavity (such as a paranasal sinus) of the subject, a controller  13  that is connected with the inserting device  12 , and a display unit  14  that is connected with the controller. The inserting device  12  is provided separately from the display unit  14  and the controller  13 . The display unit  14  is formed of an ordinary liquid crystal monitor, and capable of displaying an image acquired by a distal end portion  16  of an endoscope  15  as an image. 
     As illustrated in  FIG. 1  and  FIG. 3 , the inserting device  12  includes a holding unit  17  serving as an outer shell of the device, a cylindrical guide pipe  18  projecting from the holding unit  17 , an endoscope inserting unit  21  inserted through the inside of the guide pipe  18  and the holding unit  17 , an endoscope imaging unit  22  (imaging unit) provided inside the holding unit  17 , and a bending operation unit  34  provided on the holding unit  17 . In the present embodiment, although the endoscope  15  is separated into two units serving as the endoscope inserting unit  21  and the endoscope imaging unit  22 , the endoscope  15  may be formed by uniting these units. 
     The endoscope  15  is formed of a scanning endoscope. The whole endoscope  15  (endoscope inserting unit  21 ) is configured to have flexibility. With such structure, the endoscope inserting unit  21  inserted into the guide pipe  18  can be bent to follow the shape of the guide pipe  18 . As illustrated in  FIG. 2  and  FIG. 3 , the endoscope inserting unit  21  includes a central axis C. The endoscope inserting unit  21  is movable along the central axis C, and can be caused to project from the guide pipe  18 . 
     As illustrated in  FIG. 1  to  FIG. 3 , the endoscope inserting unit  21  includes a distal end portion  16  (distal end forming portion) positioned on the distal end side thereof in the direction of the central axis C, a flexible tube  24  provided on the proximal end side in the direction of the central axis C from the distal end portion  16 , a wire  25  (pull wire) connected to a distal end side of a sheath, a cylindrical sheath covering the distal end portion  16 , the flexible tube  24 , and the wire  25 , an illumination window  27 , a rotating unit  28 , an illumination fiber  29 , and a plurality of light-receiving fibers  31 . In the present embodiment, illustration of the sheath is omitted. The sheath has a structure capable of being bent as illustrated in  FIG. 1 , together with the endoscope inserting unit  21  (flexible tube  24 ) that is held inside thereof. The sheath is bent by pulling the wire  25  with a holding portion  43  provided on the bending operation unit  34  side. By bending the sheath, the endoscope inserting unit  21  (flexible tube  24 ) disposed inside thereof is bent. 
     The illumination fiber  29  is optically connected with a light source provided adjacent to the controller  13 . The light-receiving fibers  31  are optically connected with an imaging element  32 . Distal ends of the light-receiving fibers  31  are exposed to the outside at the distal end portion  16 . With such structure, the endoscope  15  is enabled to acquire an image at the distal end portion  16  via the light-receiving fibers  31 . 
     The wire  25  is provided inside the sheath and outside the flexible tube  24 , and extends from the holding unit  17  to the distal end portion  16 . The wire  25  is pulled to adjust the bending angle of the endoscope  15  (endoscope inserting unit  21 ). The wire  25  is an example of a linear member. The distal end of the wire  25  is fixed to the distal end portion  16  (distal end forming portion). The proximal end of the wire  25  is fixed to the holding portion  43  described later. By performing an operation to move the wire  25  forward or backward in the holding unit  17 , the endoscope inserting unit  21  can be bent in a portion in the flexible tube  24  close to the distal end portion  16 . 
     Pulling with the wire  25  corresponds to a bend in the right direction (clockwise direction) in  FIG. 1 , for example. A bend in the left direction (counterclockwise direction) in  FIG. 1  is achieved by a restoring force of the endoscope inserting unit  21  returning from a bent state pulled by the wire  25  to its original straight state. Two wires may be provided to bend the endoscope inserting unit  21 , as a matter of course. The two wires include a first wire corresponding to a rightward bend in  FIG. 1 , and a second wire corresponding to a leftward bend in  FIG. 1 . 
     As illustrated in  FIG. 2 , the endoscope imaging unit  22  includes the imaging element  32  formed of a CCD or a CMOS. The endoscope imaging unit  22  is capable of acquiring an image acquired at the distal end portion  16  of the endoscope inserting unit  21 . More specifically, the imaging element  32  converts light from the light-receiving fibers  31  into an electrical signal, and transmits the signal to the controller  13 . 
     The rotating unit  28  is electrically connected with the controller  13 . The rotating unit  28  is formed of a motor or the like, and is rocked in a spiral manner, for example, by the controller  13 . With this structure, a distal end  29 A of the illumination fiber  29  is rocked in a spiral manner in accordance with the operation of the rotating unit  28 . Accordingly, the surface of the subject to be imaged is scanned in a spiral manner with the illumination light from the illumination fiber  29 , through the distal end  29 A of the illumination fiber  29  and the illumination window  27 . The light-receiving fibers  31  receive returning light from the subject, and guide the light to the imaging element  32 . The imaging element  32  transmits the light received by the light-receiving fibers  31  as an electrical signal to the controller  13 . The controller  13  converts the electrical signal into an image, performs proper image processing on the image, and displays the image on the display unit  14 . 
     As illustrated in  FIG. 1 , the guide pipe  18  has an “L” shape as a whole, and has a cylindrical shape that is bent in an elbow shape in a middle portion. The endoscope inserting unit  21  is inserted through the inside of the guide pipe  18 . An internal wall of the guide pipe  18  is capable of guiding the endoscope inserting unit  21  that is moved forward and backward along the central axis C. 
     The guide pipe  18  is rotatable with respect to the holding unit  17 , for example. The guide pipe  18  includes a first portion  18 A that is connected with the holding unit  17 , and a second portion  18 B that extends in a direction crossing the direction in which the first portion  18 A extends. The internal diameter of the second portion  18 B is formed larger than the internal diameter of the first portion  18 A, and the endoscope inserting unit  21  can be operated to be bent inside the second portion  18 B (see  FIG. 1  and  FIG. 4 ). In the operation, the endoscope inserting unit  21  is rotatable inside the second portion  18 B, while finely adjusting the position thereof back and forth in the direction of the central axis C. In other words, the endoscope inserting unit  21  is bendable in at least one plane P including the central axis C. The endoscope inserting unit  21  may be bendable in another plane different from one plane P, as well as in the plane P. 
     The holding unit  17  has a cylindrical shape, and forms a portion that is held by the user&#39;s hand. The holding unit  17  includes a housing  33 , and the bending operation unit  34  capable of adjusting the bending angle of the endoscope  15 . 
     As illustrated in  FIG. 1  and  FIG. 2 , the bending operation unit  34  includes a dial portion  35  that is rotatable with respect to the housing  33 , and a converting portion  41  that converts rotation of the dial portion  35  into forward and backward movement of the wire  25 . The dial portion  35  includes a dial surface  36  that is formed flat, a pointer  37  (pointer projecting portion) that is provided to project from the dial surface  36 , and a first rotation transmitting portion  38  (such as a gear (gear wheel)) provided on a side opposite to the dial surface  36 . The pointer  37  is formed as a straight-line projecting portion to cross the dial surface  36 . The direction in which the pointer  37  extends can indicate an extending direction D 1  of the distal end portion  16  of the endoscope  15  (endoscope inserting unit  21 ). The concept of the bending operation unit  34  may include the controller  13 . The dial portion  35  may have any structure other than the dial, as long as it has the structure rotatable with respect to the bending operation unit  34 . For example, the dial portion  35  may have a structure of a rotary member (knob) that is rotatable with respect to the bending operation unit  34 , as a matter of course. 
     The pointer  37  projects from a surrounding portion of the dial surface  36 . This structure enables the user to recognize the indicating direction of the pointer  37  by feeling at the time when the user touches the pointer  37  by the finger, that is, tactually, not visually. The shape of the pointer  37  is an example, and may be another shape, as long as the user can tactually recognize the indicating direction. Specifically, for example, instead of the straight-line shape, the pointer  37  may have a curved shape that enables the user to easily operate the pointer  37 , or an intermittent straight-line shape in which fine projecting portions are successively aligned, or the flat dial surface  36  may be depressed to form the pointer  37 . When the bending direction of the endoscope inserting unit  21  is not two directions in one plane P but four directions in one plane P and another plane different from the plane P, the bending operation unit  34  may be achieved with a structure such as a joystick. 
     The converting portion  41  includes a substantially cylindrical cam cylinder  42  contained in the housing  33 , and the substantially cylindrical holding portion  43  (wire holding portion) provided inside the cam cylinder  42 . The cam cylinder  42  is provided with a second rotation transmitting portion  44  (such as a gear (gear wheel)) engaged with the first rotation transmitting portion  38 . As an example, the first rotation transmitting portion  38  and the second rotation transmitting portion  44  are formed as a wheel train of a bevel gear, but may be formed of other common motive power transmitting units (wheel train). 
     The internal surface of the cam cylinder  42  is provided with one or more cam grooves  45  having a spiral shape around a central axis C′ of the cam cylinder  42 . The proximal end of the wire  25  is held (fixed) on the holding portion  43 . The holding portion  43  includes a holding portion main body  46  having a cylindrical shape, and a pin  47  that projects from the holding portion main body  46  outward in the radial direction of the holding portion main body  46 . A distal end portion of the pin  47  is received in the cam groove  45 , and is slidable in the cam groove  45 . Specifically, when the dial portion  35  is rotated by the user, the cam cylinder  42  to which motive power is transmitted is rotated via the first rotation transmitting unit  38  and the second rotation transmitting unit  44 . In this manner, the holding portion  43  is moved forward or backward by the cam mechanism via the cam groove  45  and the pin  47 . In this manner, the wire  25  is pulled or returned to its original position, and the flexible tube  24  is bent or returned to its original position (initial state) in the vicinity of the distal end portion  16 . 
     In the present embodiment, the inclination of the cam groove  45 , and the gear ratio of the first rotation transmitting portion  38  and the second rotation transmitting portion  44  are set such that the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  (endoscope  15 ) agrees with the indicating direction of the pointer  37  of the bending operation unit  34 . 
     The holding unit  17  may be further provided with a moving mechanism to move backward and forward the endoscope inserting unit  21  with respect to the guide pipe  18  in the direction of the central axis C. Specifically, in a medical examination, the doctor who is the user can change the position of the endoscope inserting unit  21  using the moving mechanism or the like, or change the bending angle of the endoscope inserting unit  21  as described above, in the state where the endoscope inserting unit  21  is inserted into the cavity of the subject, to acquire a desired image in the cavity. 
     The controller  13  illustrated in  FIG. 1  is formed of, for example, an ordinary computer, and software installed in the computer and performing various types of control on the inserting device  12 . The controller  13  is capable of performing the following controls, for example, on constituent elements of the inserting device  12 . The controller  13  is capable of controlling the rotating unit  28  that rocks the illumination fiber  29 , to adjust the rotational frequency thereof or the like. The controller  13  is capable of controlling the light source, to adjust the light quantity to be supplied to the illumination fiber  29 . The controller  13  is capable of converting an electrical signal corresponding to an image acquired by the imaging element  32  of the inserting device  12  into an image, and displaying the image on the display unit  14 . 
     The following explains the operation of the endoscope system  11  according to the present embodiment, with reference to  FIG. 1  and  FIG. 4 . 
     In a medical examination, the doctor who is the user can insert the endoscope inserting unit  21  into the cavity (lumen) of the medical examinee (subject), to observe the inside of the cavity. As illustrated in  FIG. 1 , the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  in the initial state agrees with the indicating direction of the pointer  37 . In this state, the user can bend the flexible tube  24  of the endoscope inserting unit  21  using the bending operation unit  34 , to change the extending direction of the distal end portion  16  to a desired direction in one plane P. 
     When the dial portion  35  is rotated, for example, clockwise from the initial state illustrated in  FIG. 1 , the endoscope inserting unit  21  is bent rightward together with the sheath, by the operation of the cam mechanism of the converting portion  41 , as illustrated in  FIG. 4  (or as illustrated with a broken line in  FIG. 1 ). In this state, even after the endoscope inserting unit  21  is bent as illustrated in  FIG. 4 , an extending direction D 1 ′ of the distal end portion  16  of the endoscope inserting unit  21  agrees with the indicating direction of the pointer  37  of the bending operation unit  34 . The same is also applicable to the case where the dial portion  35  is rotated, for example, counterclockwise from the initial state. 
     With this structure, even in the state where the endoscope inserting unit  21  is inserted into the cavity of the medical examinee, the doctor who is the user is enabled to recognize the extending direction D 1  of the distal end portion  16 , by checking the indicating direction of the pointer  37 . In addition, because the user is enabled to recognize the indicating direction of the pointer  37  by touch (that is, tactile sensation) at the time when the pointer  37  contacts the user&#39;s hand, the user is enabled to recognize the direction observed with the distal end portion  16  without taking the his or her eyes off the display unit  14 . 
     When the guide pipe  18  is rotated with respect to the holding unit  17 , the extending direction D 1  of the distal end portion  16  does not strictly agree with the indicating direction of the pointer  37 . However, even in such a case, the bending amount of the flexible tube  24  agrees with the rotation angle of the pointer  37  from the initial state, and the rotation angle of the pointer  37  can indicate the bending amount of the flexible tube  24 . In this case, the user is enabled to recognize the bending amount of the flexible tube  24 , based on by what amount the pointer  37  is rotated from the initial state illustrated in  FIG. 1 . 
     The following can be said according to the embodiment. Specifically, the endoscope system  11  includes the holding unit  17 , the guide pipe  18  extending from the holding unit  17 , the endoscope  15  including the distal end portion  16  that is capable of acquiring an image, inserted through inside of the guide pipe  18  and bendable in at least one plane P, the bending operation unit  34  rotatably provided on the holding unit  17  and capable of adjusting a bending angle of the endoscope  15 , and the pointer  37  provided on the bending operation unit  34  and indicating the extending direction D 1  of the distal end portion  16  in the plane P. 
     With this structure, because the extending direction D 1  of the distal end portion  16  can be recognized with the pointer  37 , the user is enabled to intuitively recognize the direction observed with the distal end portion  16 , even in the state where the endoscope inserting unit  21  is inserted into the cavity of the subject. This structure prevents the user from confusing the orientation during observation of the inside of the cavity of the subject, and improves the user&#39;s convenience. In addition, even when the user performs an operation of twisting the holding unit  17  around the central axis thereof, the bending operation unit  34  and the pointer  37  move together with the holding unit  17  in one-to-one correspondence. This structure enables the user to intuitively recognize the direction in which the endoscope  15  faces. 
     In the present embodiment, the indicating direction of the pointer  37  can be tactually recognized. This structure enables the user to recognize the indicating direction of the pointer  37  without visually checking the pointer  37 , and improves the user&#39;s convenience. 
     The endoscope  15  includes a linear member to adjust the bend thereof, the bending operation unit  34  includes the dial portion  35  that is rotatably provided on the holding unit  17  and provided with the pointer  37 , and the converting portion  41  that converts rotation of the dial portion  35  into forward or backward movement of the linear member. This structure enables agreement between the indicating direction of the pointer  37  and the extending direction D 1  of the distal end portion  16 , with the simple structure using the dial portion  35  and the converting portion  41 . This structure reduces the manufacturing cost of the endoscope system  11 , and reduces the possibility of causing a malfunction in which the indicating direction of the pointer  37  does not agree with the extending direction D 1  of the distal end portion  16 . 
     The endoscope system  11  includes the display unit  14  capable of displaying the image acquired by the distal end portion  16 . This structure enables the user to intuitively recognize the extending direction of the distal end portion  16  with the pointer  37 , in the state of checking the image displayed on the display unit  14 . This structure causes the user&#39;s next operation of directing the endoscope  15  in the desired direction to be more intuitive, while the user is viewing the display unit  14 , and shortens the diagnostic time. These structures improve the user&#39;s convenience, and reduces the burden on the medical examinee (subject). 
     The following explains a first modification of the present embodiment, with reference to  FIG. 5 . The first modification explained hereinafter mainly illustrates parts that are different from the present embodiment, and explanation of parts common to the embodiment and the modification is omitted. In the embodiment, the extending direction of the distal end portion  16  of the endoscope inserting unit  21  is mechanically caused to agree with the indicating direction of the pointer  37 . In the present modification, the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  is caused to agree with the indicating direction of the pointer  37  by electrical control. 
     The holding unit  17  includes the housing  33 , and the bending operation unit  34  capable of adjusting the bending angle of the endoscope  15 . 
     The bending operation unit  34  includes the dial portion  35  rotatable with respect to the housing  33 , a sensing unit  51  sensing the rotation amount of the dial portion  35 , an actuator unit  52  to move the wire  25  forward and backward to bend the endoscope inserting unit  21  in one plane P, and the controller  13 . The dial portion  35  includes the dial surface  36  that is formed flat, a pointer  37  (pointer projecting portion) provided to project from the dial surface  36 , and a rotation axis  53  provided on a side opposite to the dial surface  36 . The sensing unit  51  is formed of, for example, a potentiometer, and is capable of reading the rotation amount (rotation angle) of the rotation axis  53 . 
     The actuator unit  52  is formed of, for example, a servo motor. For example, a sprocket is attached to an output shaft of the actuator unit  52 . The sprocket is engaged with, for example, a chain that is connected with a proximal end portion of the wire  25  that is opposite to the distal end portion of the wire  25 . The distal end portion of the wire  25  is connected with the distal end portion  16 . With such a motive power transmission mechanism, the actuator unit  52  is capable of moving the wire  25  forward and backward. By the forward and backward movement of the wire  25 , the flexible tube  24  of the endoscope inserting unit  21  can be bent in a desired direction in one plane P. The structure of the motive power transmitting mechanism is an example, and motive power may be transmitted to the wire  25  from the actuator unit  52  using another motive power transmitting mechanism, such as a mechanism using a pulley and a belt. The wire  25  is an example of the linear member. 
     The controller  13  is formed of, for example, an ordinary computer, and software installed in the computer and performs various types of control on the inserting device  12 . The controller  13  calculates the indicating direction of the pointer  37  from the rotation amount (rotation angle) of the dial portion  35  (rotation axis  53 ) sensed by the sensing unit  51 . The indicating direction of the pointer  37  is indicated with, for example, the rotation angle from a reference point. In the present modification, the reference point is a position (position corresponding to the initial state) in which the pointer  37  is disposed in  FIG. 5 . The controller  13  sets the direction indicated by the pointer  37  as a target value, when the dial portion  35  is rotated. The controller  13  controls the actuator unit  52  such that the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  agrees with the target value. The relation between the rotation angle of the actuator unit  52  and the bending angle of the flexible tube  24  of the endoscope inserting unit  21  is measured in advance, and the controller  13  controls the rotation angle of the actuator unit  52  such that the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  agrees with the target value (the indicating direction of the pointer  37 ). 
     The following is the operation of the endoscope system  11  according to the present embodiment, with reference to  FIG. 5 . 
     In a medical examination, the doctor who is the user can insert the endoscope inserting unit  21  into the cavity (into the lumen) of the medical examinee (subject), to observe the inside of the cavity. In this state, as illustrated in  FIG. 5 , the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  in the initial state agrees with the indicating direction of the pointer  37 . The user can rotate the dial portion  35  to bend the flexible tube  24  of the endoscope inserting unit  21 , and change the extending direction D 1  of the distal end portion  16  to a desired direction in one plane P. For example, suppose that the endoscope inserting unit  21  is bent to a certain bent state (for example, the state illustrated in  FIG. 4 ) from the initial state illustrated in  FIG. 5 . In this state, the controller  13  performs feedback control on the actuator unit  52 , to cause the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  to agree with the target value being the indicating direction of the pointer  37 . With this structure, also in the present modification, the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  agrees with the indicating direction of the pointer  37  of the bending operation unit  34 , even after the endoscope inserting unit  21  is bent, in the same manner as the embodiment described above. 
     Accordingly, even in the state where the endoscope inserting unit  21  is inserted into the cavity of the medical examinee, the doctor who is the user is enabled to recognize the extending direction of the distal end portion  16  by checking the indicating direction of the pointer  37 . In addition, because the user is enabled to recognize the indicating direction of the pointer  37  through tactile sensation at the time when his or her hand contacts the pointer  37 , the user is enabled to recognize the direction observed with the distal end portion  16  without taking his or her eyes off the display unit  14 . 
     According to the present modification, the bending operation unit  34  includes the dial portion  35  that is rotatably provided on the holding unit  17  and provided with the pointer  37 , the actuator unit  52  bending the endoscope  15  in one plane P, and the controller  13  controlling the actuator unit  52  such that the extending direction of the distal end portion  16  agrees with the indicating direction of the pointer  37  of the dial portion  35 . 
     This structure enables agreement between the extending direction D 1  of the distal end portion  16  and the indicating direction of the pointer  37 , also by electrical control using the controller  13 . This structure reduces the number of components used for the mechanical motive power transmitting mechanism, reduces the frequency of occurrence of a malfunction, and improves the reliability of the endoscope system  11 . 
     In the present modification, a desirable mode is a mode of using the endoscope inserting unit  21  along the direction of the central axis C, without moving the endoscope inserting unit  21  from the initial position S 1 , such that the indicating direction of the pointer  37  always agrees with the extending direction D 1  of the distal end portion  16 . In the case of the mode of moving the endoscope inserting unit  21  from the initial position S 1  along the direction of the central axis C, it is desirable to use the following second modification. 
     The following explains the second modification of the present embodiment, with reference to  FIG. 6  and  FIG. 7 . The second modification explained hereinafter mainly illustrates parts that are different from the first modification, and explanation of parts common to the first and the second modifications is omitted. Although the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  is not sensed in the second modification, the present modification has the structure in which a second sensing unit  62  is provided to always sense the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21 . In the present modification, a second dial portion  61  is provided separately from the dial portion  35  to bend the endoscope inserting unit  21 , to indicate the actual extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21 . 
     The bending operation unit  34  includes the dial portion  35  that is rotatable with respect to the housing  33 , the sensing unit  51  sensing the rotation amount of the dial portion  35 , the actuator unit  52  to move the wire  25  forward and backward to bend the endoscope inserting unit  21  in one plane P, the second dial portion  61  that is rotatable with respect to the housing  33 , the second sensing portion  62  provided on the distal end portion  16  of the endoscope inserting unit  21 , and the controller  13 . The dial portion  35  includes the dial surface  36  that is formed flat, the pointer  37  (pointer projecting portion) provided to project from the dial surface  36 , and the rotation axis  53  provided on a side opposite to the dial surface  36 . The sensing unit  51  is formed of, for example, a potentiometer, and is capable of reading the rotation amount (rotation angle) of the rotation axis  53 . 
     The second dial portion  61  is connected to the controller  13  via a second actuator unit  63  formed of a servomotor or the like. The second dial portion  61  includes a second dial surface  64  that is formed flat, a second pointer  65  (second pointer projecting portion) provided to project from the second dial surface  64 , and a second rotation axis  66  provided on a side opposite to the second dial surface  64 . The second pointer  65  of the second dial portion  61  is rotated by the second actuator unit  63  controlled by the controller  13 , and is thereby capable of indicating the inclination (inclination with respect to the ground) of the distal end portion  16  of the endoscope inserting unit  21  in one plane P. 
     The second pointer  65  is useful to recognize the actual extending direction D 1  of the distal end portion  16 , in the case where the extending direction D 1  of the distal end portion  16  is shifted from the indicating direction of the pointer  37  of the dial portion  35  when the endoscope inserting unit  21  is caused to project from the guide pipe  18  as exemplary illustrated in  FIG. 7 . 
     The second sensing unit  62  is formed of a gravity sensor (acceleration sensor). The second sensing unit  62  is capable of sensing the inclination of the distal end portion  16  of the endoscope inserting unit  21  with respect to the ground. 
     The controller  13  is formed of, for example, an ordinary computer, and software installed in the computer and performing various types of control on the inserting device. The controller  13  controls the bending amount of the flexible tube  24  of the endoscope inserting unit  21 , by operating the actuator unit  52 , based on the rotation amount (rotation angle) of the dial portion  35  (rotation axis  53 ) sensed by the sensing unit  51 . Specifically, the controller  13  controls the actuator unit  52  such that the bending amount of the flexible tube  24  increases as the rotation amount of the dial portion  35  is increased. With this structure, when the endoscope inserting unit  21  is in the initial position S 1  in the direction of the central axis C, the indicating direction of the pointer  37  agrees with the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21 , in the same manner as the first modification. 
     By contrast, the controller  13  always senses the inclination of the distal end portion  16  of the endoscope inserting unit  21  with respect to the ground, with the electrical signal transmitted from the second sensing unit  62 . The controller  13  controls the second actuator unit  63  such that the actual extending direction D 1  (inclination with respect to the ground) of the distal end portion  16  of the endoscope inserting unit  21  agrees with the indicating direction of the second pointer  65  of the second dial portion  61 . 
     The following explains the operation of the endoscope system  11  according to the present modification, with reference to  FIG. 6  and  FIG. 7 . 
     In a medical consultation, the doctor who is the user can insert the endoscope inserting unit  21  into the cavity (lumen) of the medical examinee (subject), to observe the inside of the cavity. In this state, the user can operate the dial portion  35  of the bending operation unit  34 , to bend the flexible tube  24  of the endoscope inserting unit  21 , and change the extending direction D 1  of the distal end portion  16  to a desired direction in one plane P. In this state, because the endoscope inserting unit  21  is in the initial position S 1  in the direction of the central axis C, the extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  agrees with the indicating direction of the pointer  37 , as illustrated in  FIG. 6 . 
     When the user operates the moving mechanism to change the position of the endoscope inserting unit  21  in the direction of the central axis C, a portion of the flexible tube  24  is bent along the guide pipe  18 , even when the portion is a portion other than the bending portion that is bent by the wire  25 , as illustrated in  FIG. 7 . When the endoscope inserting unit  21  is in a projecting position S 2  in which the endoscope inserting unit  21  projects from the initial position S 1  like this, the actual extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21  is shifted from the indicating direction of the pointer  37  of the dial portion  35 . However, in the present modification, the controller  13  is capable of controlling the second actuator unit  63  based on information from the second sensing unit  62 , to indicate the actual extending direction D 1  of the distal end portion  16  of the endoscope inserting unit  21 , with the second pointer  65 . Accordingly, the doctor who is the user is enabled to recognize the actual extending direction D 1  of the distal end portion D 1 , by checking the indicating direction of the second pointer  65 . In addition, because the user is enabled to recognize the indicating direction of the second pointer  65  with the tactile sensation at the time when his or her hand contacts the second pointer  65 , the user is enabled to recognize the direction observed with the distal end portion  16  without taking his or her eyes off the display unit  14 . 
     According to the present modification, even when the endoscope inserting unit  21  is in the projecting position S 2  in which the endoscope inserting unit  21  projects from the initial position S 1  to the outside of the guide pipe  18 , the user is enabled to recognize the actual extending direction D 1  of the distal end portion  16 . This structure enables the user to intuitively recognize the direction observed with the distal end portion  16 . This structure prevents the user from confusing the orientation during observation of the inside of the cavity of the subject, and improves user convenience. 
     The embodiment and the modifications have been specifically explained above with reference to drawings, but the present invention is not limited to the embodiment described above. The present invention can be realized with modified constituent elements within a range not departing from the gist thereof. Examples of the cavity of the medical examinee (subject) include a paranasal sinus, but the endoscope system  11  may be used for observation of other cavities such as the urethra and the urinary bladder, as a matter of course. Specifically, even when no (or few) landmarks exist, such that the case where the observation target of the subject is the urethra or the urinary bladder, the user is enabled to intuitively recognize the direction of the endoscope by tactile sensation via the pointer  37 . This structure enables the user to easily perform examination and screening on specific regions. In the embodiment and modifications described above, the dial portion  35  (pointer  37 ) and the second dial portion  61  (second pointer  65 ) are provided to correspond to bending in one plane P, but additional dial portions and pointers may be provided to correspond to bending in another plane (for example, a plane orthogonal to the plane P). In addition, constituent elements in the different embodiments described above may be properly used in combination to achieve an endoscope system  11 . 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.