Bone angle measuring method based on different planes

Abstract

The invention provides a bone angle measuring method based on different planes, which comprises the following steps of: (1) drawing a baseline on a baseline plane graph by using a computer tool, and marking a measuring line on a target measuring line plane graph by using the computer tool; the invention provides an angle measurer with corner combining lines in different planes. The angle measurer comprises a measuring main body, a first suction cup assembly, a pointer and a second suction cup assembly, (2) displaying a baseline planar graph through a screen of a computer, and aligning the linear hollow groove of the measurement main body to a baseline; (3) displaying a target measuring line plane graph through the computer, driving the pointer to drive the second suction cup assembly to rotate along the semicircular hollow groove, enabling the indication long groove of the pointer to be aligned with the measuring line, and pressing the second suction cup assembly to enable the second suction cup assembly to be adsorbed on the screen of the computer, so that the position of the pointer is fixed; and (4) reading the indication angle of the indication long groove corresponding to the first angle scale line, wherein the indication angle is the angle of the target angle.

Description

Technical Field

[0001] The present invention relates to the technical field of medical angle measurement, and in particular to a bone angle measurement method based on different planes. Background Art

[0002] When it is necessary to measure the femoral anteversion and humeral posterior tilt in clinical practice, since the angle lines of these bone angles are in different planes, the defined measurement method is usually adopted, that is, first find the baseline plane from the CT film (the femoral anteversion angle finds the line connecting the posterior edges of the medial and lateral femoral condyles as the baseline, and the humeral posterior tilt angle finds the line connecting the anterior edges of the medial and lateral humeral condyles as the baseline), and then find the target measurement line plane (the femoral anteversion angle finds the line connecting the center points of the femoral head and neck as the measurement line, and the humeral posterior tilt angle finds the axial line of the humeral head as the measurement line), and then technically overlap the two planes, and the intersection of the two lines is the target angle to be measured, namely the femoral anteversion angle and the humeral posterior tilt angle.

[0003] At present, when measuring such angles, clinicians usually print out the baseline plane and the target measurement line plane of the bone CT film, and then manually overlap the two planes to measure the angle of the target measurement angle. However, it is often difficult to ensure that this is implemented without deviation in clinical operations, which affects the accuracy of the measured angle and makes the measurement operation inconvenient.

[0004] Therefore, it is necessary to provide a bone angle measurement method based on different planes to accurately and effectively measure the angles of the bone target angles of the group angle line in different planes. Summary of the invention

[0005] The object of the present invention is to provide a bone angle measurement method based on different planes, so as to accurately and effectively measure the angle of the target angle of the bone group angle line in different planes.

[0006] To achieve the above-mentioned object, the present invention provides a bone angle measurement method based on different planes, comprising the following steps: (1) using a computer to open a baseline plane view of a bone CT film, using a computer tool to draw a baseline on the baseline plane view, using a computer tool to open a target measurement line plane view of the bone CT film, and using a computer tool to mark a measurement line on the target measurement line plane view; providing an angle measuring device for grouping angle lines in different planes, the angle measuring device for grouping angle lines in different planes comprising a measuring body, a first suction cup assembly, a pointer and a second suction cup assembly, a positioning center point being provided on the measuring body, a semicircular hollow groove being provided on the measuring body with the positioning center point as the center, a first angle scale line being provided along the semicircular direction of the semicircular hollow groove, and a linear hollow groove being provided along the linear direction where the two end points of the semicircular hollow groove are located; the first suction cup assembly is arranged on the measuring body; the pointer is pivotally connected to the front side of the measuring body with the positioning center point as the center, the pointer is also provided with an indicating long groove, and the pointer The second suction cup assembly is movably arranged on the indicating long groove and the semicircular hollow groove in a direction perpendicular to the measuring body; (2) the baseline plane diagram is displayed on the computer screen, the linear hollow groove of the measuring body is aligned with the baseline, and the measuring body is fixed on the computer screen by adsorbing the first suction cup assembly; (3) the target measurement line plane diagram is displayed on the computer, the second suction cup assembly is pulled up, so that the second suction cup assembly is out of contact with the computer screen, the pointer drives the second suction cup assembly to rotate along the semicircular hollow groove, so that the indicating long groove of the pointer is aligned with the measurement line, and then the second suction cup assembly is pressed so that the second suction cup assembly is adsorbed on the computer screen, so that the position of the pointer is fixed; (4) the indicating angle of the indicating long groove corresponding to the first angle scale line is read out, and the indicating angle is the angle of the target angle of the bone when collecting angle lines in different planes.

[0007] Preferably, in step (1), the baseline plane map and the target measurement line plane map are overlapped and compared to determine the intersection point between the baseline and the measurement line; and in step (2), while aligning the linear hollow groove of the measurement body with the baseline, the center point of the measurement body is aligned with the intersection point.

[0008] Preferably, in step (1), the measuring body is further provided with a second angle scale line along the semicircular direction of the semicircular hollow groove, and the scale direction of 0 to 180 degrees of the second angle scale line is opposite to the scale direction of 0 to 180 degrees of the first angle scale line; in step (4), the indication angle corresponding to the indication long groove is read out according to the first angle scale line or the second angle scale line.

[0009] Preferably, in the step (1), the two linear hollow grooves are symmetrically arranged on the measuring body with the positioning center point as the center.

[0010] Preferably, in step (1), the linear hollow groove is connected to the end of the semicircular hollow groove.

[0011] Preferably, in step (1), the first suction cup assembly includes a first suction cup connecting rod, a first suction cup body and a first suction cup limiting cap, the first suction cup connecting rod is penetrated through the measuring body, the first suction cup body is connected to one end of the first suction cup connecting rod, the first suction cup body is located on the back side of the measuring body, the first suction cup limiting cap is connected to the other end of the first suction cup connecting rod, the first suction cup limiting cap is located on the front side of the measuring body and is used to limit the first suction cup connecting rod on the measuring body.

[0012] Preferably, in the step (1), three of the first suction cup assemblies are arranged on the measuring body in a triangular distribution.

[0013] Preferably, in the step (1), the measuring body is provided with a rotating shaft at the position of the positioning center point, the pointer is rotatably mounted on the rotating shaft, and the rotating shaft is also provided with a sealing cap for preventing the pointer from falling off.

[0014] Preferably, in step (1), the second suction cup assembly includes a second suction cup connecting rod, a second suction cup body and a second suction cup limiting cap, the second suction cup connecting rod is movably arranged on the indicating long groove and the semicircular hollow groove in a direction perpendicular to the measuring body, the second suction cup body is connected to one end of the second suction cup connecting rod, the second suction cup body is located on the back side of the measuring body, the second suction cup limiting cap is connected to the other end of the second suction cup connecting rod, the second suction cup limiting cap is located on the front side of the measuring body, and the second suction cup limiting cap is used to limit the second suction cup connecting rod.

[0015] Preferably, in step (1), the measuring body is a transparent structure, or a hollow structure for observing the measuring line of the bone group angle line is provided at the middle position of the measuring body.

[0016] Compared with the prior art, the bone angle measurement method based on different planes of the present invention first draws the baseline of the baseline plane of the CT film by computer and marks the measurement line on the plane of the target measurement line, then uses the linear hollow groove of the measurement body to match the baseline drawn by the baseline plane on the computer, and uses the first suction cup assembly to fix the measurement body on the computer screen to ensure that the measurement body will not deviate during the measurement process, and then after switching to the plane of the target angle measurement line on the computer screen, the pointer is driven to rotate and drive the second suction cup assembly, so that the pointer's indicating long groove is aligned with the measurement line drawn by the plane of the target angle measurement line on the computer, and the pointer is fixed at the position of the computer by the second suction cup assembly to ensure that the pointer will not deviate during the measurement process, and then the first angle scale line of the measurement body can quickly measure the target angle angle of the bone group angle line in different planes. Therefore, the bone angle measurement method based on different planes of the present invention can accurately and effectively measure the angle of the target angle of the bone group angle line in different planes, and the operation is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional structural diagram of the angle measuring device of the angle group line in different planes of the present invention.

[0018] Figure 2 yes Figure 1 Front view of the goniometer showing the angle lines in different planes.

[0019] Figure 3 yes Figure 1 Rear view of the goniometer showing the angle lines in different planes.

[0020] Figure 4 It is a structural diagram of another embodiment of the angle measuring device for group diagonal lines in different planes of the present invention.

[0021] Figure 5 It is a structural diagram of the connection between the rotating shaft and the sealing cap of the angle measuring device of the angle measuring device of the angle measuring device in different planes of the present invention.

[0022] Figure 6 It is a structural diagram of the first suction cup assembly of the angle measuring device for combining diagonal lines in different planes of the present invention.

[0023] Figure 7 It is a structural diagram of the second suction cup assembly of the angle measuring device for combining diagonal lines in different planes of the present invention. DETAILED DESCRIPTION

[0024] In order to explain the technical content and structural features of the present invention in detail, further description will be given below in combination with the implementation modes and the accompanying drawings.

[0025] Embodiment 1:

[0026] See also Figures 1 to 3 The bone angle measurement method based on different planes of the present invention comprises the following steps:

[0027] S11, using a computer to open the baseline plane of the bone CT film, using a computer tool to draw the baseline on the baseline plane, using a computer to open the target measurement line plane of the bone CT film, and using a computer tool to mark the measurement line on the target measurement line plane; providing an angle measuring device 100 for combining angle lines in different planes, the angle measuring device 100 for combining angle lines in different planes includes a measuring body 1, a first suction cup assembly 2, a pointer 3 and a second suction cup assembly 4, a positioning center point is provided on the measuring body 1, and a semicircular hollow groove 1 is provided on the measuring body 1 with the positioning center point as the center 1, a measuring body 1 is provided with a first angle scale line 12 along the semicircular direction of the semicircular hollow groove 11, and a linear hollow groove 13 is provided along the linear direction where the two end points of the semicircular hollow groove 11 are located; a first suction cup assembly 2 is arranged on the measuring body 1; a pointer 3 is pivotally connected to the front of the measuring body 1 with the positioning center point as the center, and an indicating long groove 31 is also provided on the pointer 3, and the indicating long groove 31 is connected to the semicircular hollow groove 11; a second suction cup assembly 4 is movably arranged on the indicating long groove 31 and the semicircular hollow groove 11 along a direction perpendicular to the measuring body 1;

[0028] S12, displaying the baseline plane diagram on the computer screen, aligning the linear hollow groove 13 of the measuring body 1 with the baseline, and adsorbing the measuring body 1 on the computer screen through the first suction cup assembly 2, thereby fixing the measuring body 1 on the computer screen;

[0029] S13, through the computer display showing the plane diagram of the target measurement line, the second suction cup assembly 4 is pulled up so that the second suction cup assembly 4 is out of contact with the computer screen, the pointer 3 drives the second suction cup assembly 4 to rotate along the semicircular hollow groove 11 so that the indicating long groove 31 of the pointer 3 is aligned with the measurement line, and then the second suction cup assembly 4 is pressed so that the second suction cup assembly 4 is adsorbed on the computer screen, thereby fixing the position of the pointer 3;

[0030] S14, reading out the indicated angle of the indicating long groove 31 corresponding to the first angle scale line 12, where the indicated angle is the target angle of the bone when collecting angle lines in different planes.

[0031] Embodiment 2:

[0032] S21, using a computer to open the baseline plane of the bone CT film, using a computer tool to draw a baseline on the baseline plane, using a computer to open the target measurement line plane of the bone CT film, using a computer tool to mark the measurement line on the target measurement line plane; overlapping the baseline plane and the target measurement line plane and comparing them to establish the intersection point of the baseline and the measurement line; providing an angle measuring device 100 for combining angle lines in different planes, the angle measuring device 100 for combining angle lines in different planes includes a measuring body 1, a first suction cup assembly 2, a pointer 3 and a second suction cup assembly 4, the measuring body 1 is provided with a positioning center point, the measuring body 1 is provided with a semicircular hollow groove 11 with the positioning center point as the center, the measuring body 1 is provided with a first angle scale line 12 along the semicircular direction of the semicircular hollow groove 11, and the measuring body 1 is provided with a linear hollow groove 13 along the linear direction where the two end points of the semicircular hollow groove 11 are located; the first suction cup assembly 2 is arranged on the measuring body 1; the pointer 3 is pivotally connected to the front of the measuring body 1 with the positioning center point as the center, and the pointer 3 is also provided with an indicating long groove 31, and the indicating long groove 31 is connected with the semicircular hollow groove 11; the second suction cup assembly 4 is movably arranged on the indicating long groove 31 and the semicircular hollow groove 11 along a direction perpendicular to the measuring body 1;

[0033] S22, the baseline plane diagram is displayed on the computer screen, the straight hollow groove 13 of the measuring body 1 is aligned with the baseline, and at the same time, the center point of the measuring body 1 is aligned with the intersection point, and the measuring body 1 is adsorbed on the computer screen through the first suction cup assembly 2, so that the measuring body 1 is fixed on the computer screen;

[0034] S23, through the computer display showing the plane diagram of the target measurement line, the second suction cup assembly 4 is pulled up so that the second suction cup assembly 4 is out of contact with the computer screen, the pointer 3 is driven to drive the second suction cup assembly 4 to rotate along the semicircular hollow groove 11 so that the indicating long groove 31 of the pointer 3 is aligned with the measurement line, and then the second suction cup assembly 4 is pressed so that the second suction cup assembly 4 is adsorbed on the computer screen, thereby fixing the position of the pointer 3;

[0035] S24, reading out the indicated angle of the indicating long groove 31 corresponding to the first angle scale line 12, where the indicated angle is the target angle of the bone for collecting angle lines in different planes.

[0036] It is worth noting that the baseline plane image and the target measurement line plane image of the above-mentioned bone CT films are CT films under the same conditions, and the changes in different planes are reflected in the evolution of the real anatomical data of the bones.

[0037] The bone CT film may be a full-length femur CT film or a full-length humerus CT film. For a full-length femur CT film, the bone angle measurement method based on different planes of the present invention may be used to measure the femoral anteversion angle; for a full-length humerus CT film, the bone angle measurement method based on different planes of the present invention may be used to measure the humeral posterior tilt angle, but the present invention is not limited thereto.

[0038] In an optional embodiment, in the above step S11 or step S21, the measuring body 1 is further provided with a second angle scale line 14 along the semicircular direction of the semicircular hollow groove 11, and the scale direction of the second angle scale line 14 from 0 to 180 degrees is opposite to the scale direction of the first angle scale line 12 from 0 to 180 degrees; in the above step S14 or step S24, the indicated angle corresponding to the indicating long groove 31 is read according to the first angle scale line 12 or the second angle scale line 14. Further, the semicircular hollow groove 11 is located between the first angle scale line 12 and the second angle scale line 14. However, this is not limited thereto.

[0039] In an optional embodiment, in the above step S11 or step S21, two linear hollow grooves 13 are symmetrically arranged on the measuring body 1 with the positioning center point as the center. However, the number of the linear hollow grooves 13 is not limited thereto, for example, the number of the linear hollow grooves 13 can also be one or three, etc.

[0040] In an optional embodiment, in the above step S11 or step S21, the linear hollow groove 13 is connected to the end of the semicircular hollow groove 11. However, this is not limited to this. For example, in other embodiments, the linear hollow groove 13 may be configured not to be connected to the end of the semicircular hollow groove 11.

[0041] In an optional embodiment, in the above step S11 or step S21, the first suction cup assembly 2 includes a first suction cup connecting rod 21, a first suction cup body 22 and a first suction cup limiting cap 23, the first suction cup connecting rod 21 is penetrated through the measuring body 1, the first suction cup body 22 is connected to one end of the first suction cup connecting rod 21, the first suction cup body 22 is located on the back side of the measuring body 1, the first suction cup limiting cap 23 is connected to the other end of the first suction cup connecting rod 21, the first suction cup limiting cap 23 is located on the front side of the measuring body 1 and is used to limit the first suction cup connecting rod 21 on the measuring body 1. In the above step S12 or step S22, the first suction cup body 22 is adsorbed on the computer screen to fix the measuring body 1. However, the structure of the first suction cup assembly 2 is not limited thereto.

[0042] In an optional embodiment, in the above step S11 or step S21, three first suction cup assemblies 2 are arranged on the measuring body 1 in a triangular distribution, so that the measuring body 1 can be firmly fixed on the computer screen. However, the number of the first suction cup assemblies 2 is not limited thereto.

[0043] In an optional embodiment, in the above step S11 or step S21, the measuring body 1 is provided with a rotating shaft 15 at the position of the positioning center point, the pointer 3 is rotatably mounted on the rotating shaft 15, and the rotating shaft 15 is also provided with a sealing cap 16 for preventing the pointer 3 from falling off.

[0044] In an optional embodiment, in the above-mentioned step S11 or step S21, the second suction cup assembly 4 includes a second suction cup connecting rod 41, a second suction cup body 42 and a second suction cup limiting cap 43, the second suction cup connecting rod 41 is movably arranged on the indicating long groove 31 and the semicircular hollow groove 11 in a direction perpendicular to the measuring body 1, the second suction cup body 42 is connected to one end of the second suction cup connecting rod 41, the second suction cup body 42 is located on the back side of the measuring body 1, the second suction cup limiting cap 43 is connected to the other end of the second suction cup connecting rod 41, the second suction cup limiting cap 43 is located on the front side of the measuring body 1, and the second suction cup limiting cap 43 is used to limit the second suction cup connecting rod 41. Specifically, in the above-mentioned step S13 or step S23, by pulling the second suction cup limiting cap 43 of the second suction cup assembly 4, the second suction cup connecting rod 41 drives the second suction cup body 42 to move, so that the second suction cup body 42 is detached from the computer screen, and then the pointer 3 can drive the second suction cup assembly 4 to move along the semicircular hollow groove 11 of the measuring body 1, and by pressing the second suction cup limiting cap 43 of the second suction cup assembly 4, the second suction cup connecting rod 41 drives the second suction cup body 42 to move, so that the second suction cup body 42 moves and is adsorbed on the computer screen, thereby fixing the position of the pointer 3 to prevent the pointer 3 from shifting.

[0045] In an optional embodiment, in the above step S11 or step S21, the measuring body 1 is a transparent structure, or a hollow structure 17 for observing the measuring line of the bone group angle line is provided in the middle of the measuring body 1. Figures 1 to 3 As shown, in one embodiment, a hollow structure 17 for observing the measurement line of the bone group angle line is provided at the middle position of the measurement body 1. The hollow structure 17 can be used to display the measurement line drawn by the plane diagram of the target angle measurement line on the computer, so that the doctor can quickly align the indicating slot 31 of the pointer 3 with the measurement line. Figure 4 As shown, in another embodiment, the measuring body 1 may also be a transparent structure, which can also facilitate the doctor to quickly align the indicating slot 31 of the pointer 3 with the measuring line.

[0046] In summary, the bone angle measurement method based on different planes of the present invention first uses a computer to draw the baseline of the baseline plane of the CT film and marks the measurement line on the target measurement line plane, and then uses the linear hollow groove 13 of the measuring body 1 to match the baseline drawn on the computer using the baseline plane, and uses the first suction cup assembly 2 to fix the measuring body 1 on the computer screen to ensure that the measuring body 1 will not deviate during the measurement process, and then after switching to the plane of the target angle measurement line on the computer screen, the pointer 3 is driven to rotate and drive the second suction cup assembly 4, so that the indicating long groove 31 of the pointer 3 is aligned with the measurement line drawn on the computer using the plane of the target angle measurement line, and the pointer 3 is fixed at the position of the computer using the second suction cup assembly 4 to ensure that the pointer 3 will not deviate during the measurement process, and then the first angle scale line 12 of the measuring body 1 can quickly measure the target angle angle of the bone group angle line in different planes. Therefore, the bone angle measurement method based on different planes of the present invention can accurately and effectively measure the angle of the target angle of the bone group angle line in different planes, and the operation is simple and convenient.

[0047] The above disclosure is only a preferred embodiment of the present invention, which cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are all within the scope of the present invention.

Claims

1. A method for measuring bone angles based on different planes, characterized in that: The following steps are involved: (1) using a computer to open a baseline plane view of a bone CT film, using a computer tool to draw a baseline on the baseline plane view, using a computer tool to open a target measurement line plane view of the bone CT film, and using a computer tool to mark a measurement line on the target measurement line plane view; Provided is an angle measuring device for group angle lines in different planes, the angle measuring device for group angle lines in different planes comprises a measuring body, a first suction cup assembly, a pointer and a second suction cup assembly, the measuring body is provided with a positioning center point, the measuring body is provided with a semicircular hollow groove with the positioning center point as the center, the measuring body is provided with a first angle scale line along the semicircular direction of the semicircular hollow groove, and the measuring body is provided with a linear hollow groove along the straight line direction where the two end points of the semicircular hollow groove are located; the first suction cup assembly is arranged on the measuring body; the pointer is pivotally connected to the front side of the measuring body with the positioning center point as the center, the pointer is also provided with an indicating long groove, and the indicating long groove is connected with the semicircular hollow groove; the second suction cup assembly is movably arranged on the indicating long groove and the semicircular hollow groove in a direction perpendicular to the measuring body; (2) The baseline plane diagram is displayed on the computer screen, the linear hollow groove of the measuring body is aligned with the baseline, and the measuring body is adsorbed on the computer screen by the first suction cup assembly, thereby fixing the measuring body on the computer screen; (3) by displaying the plane diagram of the target measurement line on the computer, the second suction cup assembly is lifted so that the second suction cup assembly is out of contact with the computer screen, the pointer drives the second suction cup assembly to rotate along the semicircular hollow groove so that the indicating long groove of the pointer is aligned with the measurement line, and then the second suction cup assembly is pressed so that the second suction cup assembly is adsorbed on the computer screen, thereby fixing the position of the pointer; (4) Reading out the indicated angle of the indicating long groove corresponding to the first angle scale line, wherein the indicated angle is the target angle of the bone when collecting angle lines in different planes.

2. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the baseline plane map and the target measurement line plane map are overlapped and compared to determine the intersection point between the baseline and the measurement line; in the step (2), while aligning the linear hollow groove of the measurement body with the baseline, the center point of the measurement body is aligned with the intersection point.

3. The bone angle measurement method based on different planes according to claim 1, characterized in that: In step (1), the measuring body is further provided with a second angle scale line along the semicircular direction of the semicircular hollow groove, and the scale direction of the second angle scale line from 0 to 180 degrees is opposite to the scale direction of the first angle scale line from 0 to 180 degrees; in step (4), the indication angle corresponding to the indication long groove is read out according to the first angle scale line or the second angle scale line.

4. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the two linear hollow grooves are symmetrically arranged on the measuring body with the positioning center point as the center.

5. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the linear hollow groove is connected to the end of the semicircular hollow groove.

6. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the first suction cup assembly includes a first suction cup connecting rod, a first suction cup body and a first suction cup limiting cap, the first suction cup connecting rod is penetrated through the measuring body, the first suction cup body is connected to one end of the first suction cup connecting rod, the first suction cup body is located on the back side of the measuring body, the first suction cup limiting cap is connected to the other end of the first suction cup connecting rod, the first suction cup limiting cap is located on the front side of the measuring body and is used to limit the first suction cup connecting rod on the measuring body.

7. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the three first suction cup assemblies are arranged on the measuring body in a triangular distribution.

8. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the measuring body is provided with a rotating shaft at the position of the positioning center point, the pointer is rotatably mounted on the rotating shaft, and the rotating shaft is also provided with a sealing cap for preventing the pointer from falling off.

9. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the second suction cup assembly includes a second suction cup connecting rod, a second suction cup body and a second suction cup limiting cap, the second suction cup connecting rod is movably arranged on the indicating long groove and the semicircular hollow groove in a direction perpendicular to the measuring body, the second suction cup body is connected to one end of the second suction cup connecting rod, the second suction cup body is located on the back side of the measuring body, the second suction cup limiting cap is connected to the other end of the second suction cup connecting rod, the second suction cup limiting cap is located on the front side of the measuring body, and the second suction cup limiting cap is used to limit the second suction cup connecting rod.

10. The bone angle measurement method based on different planes according to claim 1, characterized in that: In the step (1), the measuring body is a transparent structure, or a hollow structure for observing the measuring line of the bone group angle line is provided at the middle position of the measuring body.

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