Device and method for measuring cross sectional area of tendon

Abstract

The invention belongs to the technical field of medical instrument evaluation, particularly relates to a tendon cross-sectional area measuring device and a tendon cross-sectional area measuring method, and provides the tendon cross-sectional area measuring device and the tendon cross-sectional area measuring method on the basis of a volumetric method and a die forming technology. The long and thin cylindrical measuring cylinder is used for containing normal saline, the pressure sensor is used for measuring the hydraulic pressure change caused by the fact that the tendon is immersed in the normal saline, then the liquid volume change is obtained, and the average cross sectional area of the tendon under the corresponding displacement is obtained based on the displacement of the tendon immersed in the liquid. Further, the minimum point of the tendon cross section area is accurately measured, and a reference is provided for a later tensile test.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of medical device evaluation, and particularly relates to a tendon cross-sectional area measuring device and a measuring method. BACKGROUND

[0002] Tendon is a kind of dense connective tissue, which plays a supporting, connecting and protecting role in the human body. The cross-sectional area of the tendon is an important parameter for evaluating its mechanical properties. In order to measure the cross-sectional area of the tendon, a series of measurement methods have been proposed by domestic and foreign scholars: section method, which measures the morphology by sectioning the tendon. The data measured by this method is relatively accurate, but the technology is destructive and cannot be used for subsequent mechanical testing; area micrometer method, which measures the height of the tendon compressed into a rectangular groove to determine the cross-sectional area of the tendon. When using this method to measure, irreversible damage to the sample may occur, resulting in a decrease in the mechanical properties of the sample; volume method, which measures the volume of the sample divided by the length to calculate the cross-sectional area of the sample. Geometric approximation method, which approximates the cross-section of the sample as a right triangle, a circle or an ellipse, and then measures its size with a tool. Although these two methods are convenient, errors cannot be avoided, and such data are not useful for evaluating the mechanical properties of the sample; structured light scanning method, which calculates the cross-sectional area of the sample by scanning in all directions and reconstructing a three-dimensional digital model of the soft tissue. However, there may be potential limitations in the coincidence during the scanning process and the cost of the equipment.

[0003] In recent years, the mold technology is a relatively ideal measurement method. For example, Chinese patent document CN111184516A discloses a mold device and a positionable soft tissue cross-sectional area measuring method. The mold material is used to mold and demold the sample, which can well "copy" the sample. Moreover, the related scholars mark the sample before molding, test the mechanical properties of the sample after demolding, locate the corresponding position of the model according to the marking of the sample fracture part, and then calculate the cross-sectional area at this position by using optical measurement means or image analysis software. Although this method is economical and does not cause damage to the sample, the molding and demolding process is relatively complex and has a high time cost. The measurement of the cross-sectional area is calculated by projecting the mold section using optical measurement equipment or image analysis software. As is known, this method has a relatively strict requirement for the edge profile of the sample, and the actual profile of the section cannot be clearly and accurately described, which further increases the measurement error. SUMMARY

[0004] To solve the above technical problems, the present application provides a kind of tendon cross-sectional area measuring device and measuring method based on volume method and mold forming technology, since the cross-sectional area of tendon is small, in order to improve the measurement accuracy, the present application uses slender cylindrical measuring cylinder to hold physiological saline, uses pressure sensor to measure the hydraulic change caused by tendon immersed in physiological saline, and then obtains the liquid volume change, and then obtains the average cross-sectional area of tendon under the corresponding displacement based on the displacement of tendon immersed in liquid, and then accurately measures the minimum point of tendon cross-sectional area, to provide reference for later stretching test.

[0005] The technical problem to be solved by the present application is realized by the following technical scheme: a tendon cross-sectional area measuring device, comprising a base, a measuring cylinder, a load, a pressure sensor, a lowering device and a cross-sectional area measuring module; The measuring cylinder is vertically arranged on the base and used for placing physiological saline; The measuring cylinder is slender cylindrical; The load is arranged in the measuring cylinder, and the density of the load is greater than the density of physiological saline; The load is connected with the lower end of the tendon, and used for straightening the tendon and vertically entering the physiological saline; The lowering device is connected with the upper end of the tendon, and used for controlling the lowering of the tendon and the load; The pressure sensor is arranged at the bottom of the measuring cylinder and electrically connected with the cross-sectional area measuring module; The cross-sectional area measuring module is used for converting the pressure variable measured by the pressure sensor into the volume variable of physiological saline, and obtaining the average cross-sectional area of tendon under the corresponding displacement based on the corresponding displacement of the load.

[0006] Preferably, the diameter of the measuring cylinder is less than 3 times the maximum outer diameter of the tendon, and the length of the measuring cylinder is more than 1.5 times the corresponding length in the natural state of the tendon. The diameter of the measuring cylinder is controlled to be less than 3 times the maximum outer diameter of the tendon to more sensitively perceive the small volume change and hydraulic change caused by the tendon, thereby improving the measurement accuracy. Since the tendon is in a stretched state, the length of the measuring cylinder is set to be more than 1.5 times the corresponding length in the natural state of the tendon to meet the measurement requirements. The natural state of the tendon refers to the state when the tendon is not stretched.

[0007] Preferably, a lower clamp is arranged above the load. The lower clamp clamps the lower end of the tendon, so that the lower end of the tendon is connected with the load.

[0008] Preferably, the load is a weight, and the lower clamp is a dovetail clamp connected with the upper end of the weight. The dovetail clamp is connected with the weight, which has a simple structure and can be quickly connected with the tendon.

[0009] Preferably, the lowering device comprises a linear drive module, a cantilever and an upper clamp. The linear drive module is vertically arranged on the base and is used for controlling the up-and-down sliding of the cantilever; The upper clamp is arranged below the cantilever, the upper end of the tendon is clamped by the upper clamp, the up-and-down sliding of the cantilever is controlled by the linear drive mechanism, and the purpose of controlling the lowering of the tendon and the load is achieved.

[0010] Preferably, the upper clamp comprises a sliding seat, a sliding rail, a bidirectional screw rod, a clamping jaw and a knob. The sliding rail is arranged on the sliding seat, and the sliding seat is installed below the cantilever. The bidirectional screw rod is rotatably arranged on the sliding seat. Two clamping jaws are arranged at two ends of the bidirectional screw rod respectively and are in sliding connection with the sliding rail. The knob is coaxially connected with the bidirectional screw rod.

[0011] Preferably, the device further comprises leveling feet, an attitude instrument and a buffer support column, the leveling feet are arranged below four corners of the base, and the leveling feet are in threaded connection with the base. The buffer support column is arranged between the measuring cylinder and the base. The attitude instrument is arranged on the base and is used for measuring the angle between the base and the horizontal plane, the angle between the base and the horizontal plane is measured by the attitude instrument, the angle between the base and the horizontal plane is adjusted by the leveling feet, the liquid level of the physiological saline is ensured to be parallel to the horizontal plane, and the influence of the inclination of the base on the measurement result is avoided.

[0012] Preferably, the device further comprises a display screen, and the display screen is used for displaying the liquid level of the physiological saline, the liquid level increment of the physiological saline, the sampling length and the cross-sectional area corresponding to the sampling length.

[0013] The device further discloses a tendon cross-sectional area measuring method, the physiological saline is poured into the measuring cylinder by using the tendon cross-sectional area measuring device. The upper end of the tendon is installed on the lowering device, the load is hung below the tendon, the starting point and the ending point are marked below and above the tendon respectively, and the starting point on the tendon is located above the load. The tendon is lowered into the measuring cylinder by using the lowering device, and the starting point of the tendon reaching the liquid level is taken as the starting point of the test. The tendon is controlled to descend at a preset speed by using the lowering device until the ending point of the tendon. The pressure sensor is used for detecting the hydraulic pressure value of the physiological saline in real time. The pressure variable detected by the pressure sensor is converted into the volume variable of the physiological saline by using the cross-sectional area measuring module, and the average cross-sectional area of the tendon under the corresponding displacement amount of the load is obtained based on the corresponding displacement amount of the load. With displacement amount H as a test unit, the average cross-sectional area corresponding to each displacement amount H during the descending process of the tendon is tested, and a cross-sectional area curve of the tendon is obtained with displacement amount as the abscissa and the cross-sectional area of the tendon as the ordinate, so that the lowest point of the curve is the thinnest point of the tendon, and the change of the point is focused on in the stretching experiment.

[0014] Preferably, the pressure variable measured by the pressure sensor is converted into the volume variable of the physiological saline by the cross-sectional area measurement module, the liquid level change is obtained based on the cross-sectional area of the measuring cylinder, and the time (t) - liquid level change value (h) graph is drawn by the numerical value of the liquid level change and the speed of the tendon immersed in the liquid, so that the minimum slope point is obtained as the thinnest point of the tendon, the cross-sectional area of the point is calculated, and the average cross-sectional area within 5mm above and below the point is calculated, and the change of the point is focused on in the stretching experiment.

[0015] Compared with the prior art, the beneficial effects of the present application are: The tendon cross-sectional area measuring device of the present application contains physiological saline with known density in the measuring cylinder. Since the cross-sectional area of the measuring cylinder is constant, the liquid level change is not affected by the cross-sectional area of the measuring cylinder. In addition, the density of the load is greater than that of the physiological saline, so the tendon can be straightened and vertically immersed in the physiological saline by connecting the load to the lower end of the tendon. By connecting the lowering device to the upper end of the tendon, the vertical downward movement of the tendon and the load is controlled by the lowering device. Based on the density of the physiological saline, the pressure difference caused by the change of the liquid level can be measured by the pressure sensor at the bottom of the measuring cylinder, and the variable of the liquid level can be obtained. Based on the corresponding displacement amount of the load, the average cross-sectional area of the tendon under the corresponding displacement amount can be obtained, the cross-sectional area of the tendon can be measured quickly, and the tendon product can not be damaged, and subsequent stretching test can be performed.

[0016] Since the cross-sectional area of the tendon is small, the measuring cylinder of the present application is in the form of an elongated cylindrical shape, which can more sensitively perceive the volume change and hydraulic pressure change caused by the tendon immersed in the physiological saline. The present application measures the pressure change caused by the change of the liquid level by using the hydraulic pressure sensor, and then converts it into volume change, which is suitable for measuring small volume changes and improves the measurement accuracy. In addition, the physiological saline avoids affecting the volume of the tendon. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The structure diagram of the tendon cross-sectional area measuring device of the present application is shown in the figure; Figure 2 The perspective view of the tendon cross-sectional area measuring device of the present application is shown in the figure; Figure 3 The structure diagram of the upper clamp of the present application is shown in the figure; Figure 4 The schematic diagram of the display screen of the present application is shown in the figure; In the diagram, there are 100 bases, 1 measuring cylinder, 2 loads, 3 pressure sensors, and 4 lowering devices. 41 Linear drive module, 42 Cantilever, 43 Upper clamp; 431 Sliding seat, 432 Slide rail, 433 Bidirectional lead screw, 434 Clamp, 435 Knob; 5. Leveling feet, 6. Attitude gauge, 7. Buffer support column, 8. Display screen. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0019] like Figures 1-4 As shown, a tendon cross-sectional area measuring device includes a base 100, a measuring cylinder 1, a load 2, a pressure sensor 3, a lowering device 4, and a cross-sectional area measuring module.

[0020] The measuring cylinder 1 is vertically mounted on the base 100 and is used to hold physiological saline.

[0021] The measuring cylinder 1 is a long and slender cylindrical shape.

[0022] The load 2 is placed inside the measuring cylinder 1, and the density of the load 2 is greater than the density of the physiological saline.

[0023] The load 2 is connected to the lower end of the tendon and is used to straighten the tendon and allow it to enter the saline solution vertically.

[0024] The lowering device 4 is connected to the upper end of the tendon and is used to control the lowering of the tendon and the load 2.

[0025] The pressure sensor 3 is located at the bottom of the measuring cylinder 1 and is electrically connected to the cross-sectional area measurement module.

[0026] The cross-sectional area measurement module is used to convert the pressure variable measured by the pressure sensor 3 into the volume variable of physiological saline, and to obtain the average cross-sectional area of ​​the tendon under the corresponding displacement based on the corresponding displacement of the load 2.

[0027] The diameter of the measuring cylinder 1 is less than three times the maximum outer diameter of the tendon. The diameter of the measuring cylinder 1 is less than 20 cm. The length of the measuring cylinder 1 is more than 1.5 times the corresponding length of the tendon in its natural state.

[0028] A lower clamp is provided above the load 2.

[0029] The load 2 is a weight, and the lower clamp is a dovetail clamp connected to the upper end of the weight.

[0030] like Figure 2 As shown, the lowering device 4 includes a linear drive module 41, a cantilever 42, and an upper clamp 43.

[0031] The linear drive module 41 is vertically arranged on the base 100, and is used to control the up-and-down sliding of the cantilever 42.

[0032] The upper clamp 43 is arranged below the cantilever 42.

[0033] As shown in Figure 3 The upper clamp 43 comprises a sliding seat 431, a sliding rail 432, a bidirectional screw rod 433, a clamping jaw 434 and a knob 435.

[0034] The sliding rail 432 is arranged on the sliding seat 431, and the sliding seat 431 is installed below the cantilever 42.

[0035] The bidirectional screw rod 433 is rotatably arranged on the sliding seat 431.

[0036] Two clamping jaws 434 are respectively arranged at two ends of the bidirectional screw rod 433, and are in sliding connection with the sliding rail 432.

[0037] The knob 435 is coaxially connected with the bidirectional screw rod 433.

[0038] As shown in Figure 1 The tendon cross-sectional area measuring device further comprises a leveling foot 5, a posture instrument 6 and a buffer support column 7, the leveling foot 5 is arranged below four corners of the base 100, and the leveling foot 5 is in threaded connection with the base 100.

[0039] The buffer support column 7 is arranged between the measuring cylinder 1 and the base 100.

[0040] The posture instrument 6 is arranged on the base 100, and is used to measure the angle between the base 100 and the horizontal plane.

[0041] As shown in Figure 1 and Figure 4 The tendon cross-sectional area measuring device further comprises a display screen 8, which is used to display the liquid level of the physiological saline, the liquid level increment of the physiological saline, the sampling length and the cross-sectional area corresponding to the sampling length.

[0042] A tendon cross-sectional area measuring method is provided, which utilizes the tendon cross-sectional area measuring device, and the measuring cylinder 1 is filled with physiological saline.

[0043] The upper end of the tendon is installed on the lowering device 4, and the load 2 is hung at the lower end of the tendon, and the starting point and the ending point are marked below and above the tendon respectively, and the starting point on the tendon is above the load 2.

[0044] The tendon is lowered into the measuring cylinder 1 by the lowering device 4, and the starting point of the test is reached when the starting point of the tendon reaches the liquid surface.

[0045] The tendon is controlled to descend at a preset speed until the end point of the tendon by the lowering device 4.

[0046] The hydraulic value of the physiological saline is detected in real time by the pressure sensor 3.

[0047] The pressure variable measured by the pressure sensor 3 is converted into the volume variable of the physiological saline by the cross-sectional area measurement module, and the average cross-sectional area of the tendon corresponding to the displacement of the load 2 is obtained.

[0048] The average cross-sectional area corresponding to each displacement H of the tendon during the descending process is taken as the test unit, and the cross-sectional area curve of the tendon is obtained by taking the displacement as the abscissa and the cross-sectional area of the tendon as the ordinate, and the lowest point of the curve is the thinnest point of the tendon, which is focused on in the stretching experiment. In this embodiment, the displacement H is taken as the sampling length.

[0049] In addition, the present embodiment also has a method, the pressure variable measured by the pressure sensor 3 is converted into the volume variable of the physiological saline by the cross-sectional area measurement module, the liquid level change is obtained based on the cross-sectional area of the measuring cylinder 1, and the time (t) - liquid level change value (h) graph is made by the numerical value of the liquid level change and the speed of the tendon immersed in the liquid, so as to obtain the smallest slope point as the thinnest point of the tendon, calculate the cross-sectional area of the point and the average cross-sectional area within 5 mm above and below the point, and focus on the change of the point in the stretching experiment.

Claims

1. A tendon cross-sectional area measuring device, characterized by: The application relates to a device for measuring the cross-sectional area of a tendon, which comprises a base (100), a measuring cylinder (1), a load (2), a pressure sensor (3), a lowering device (4) and a cross-sectional area measuring module. The measuring cylinder (1) is vertically arranged on the base (100) and used for placing physiological saline. The measuring cylinder (1) is in an elongated cylindrical shape. The load (2) is arranged in the measuring cylinder (1), and the density of the load (2) is greater than that of the physiological saline. The load (2) is connected with the lower end of the tendon and used for straightening and vertically placing the tendon into the physiological saline. The lowering device (4) is connected with the upper end of the tendon and used for controlling the lowering of the tendon and the load (2). The pressure sensor (3) is arranged at the bottom of the measuring cylinder (1) and electrically connected with the cross-sectional area measuring module. The cross-sectional area measuring module is used for converting the pressure variable measured by the pressure sensor (3) into the volume variable of the physiological saline and obtaining the average cross-sectional area of the tendon under the corresponding displacement of the load (2).

2. The tendon cross-sectional area measuring device of claim 1, wherein: The diameter of the measuring cylinder (1) is less than 3 times of the maximum outer diameter of the tendon, and the length of the measuring cylinder (1) is greater than 1.5 times of the corresponding length of the tendon in a natural state.

3. The tendon cross-sectional area measuring device of claim 1, wherein: A lower clamp is arranged above the load (2).

4. The tendon cross-sectional area measuring device of claim 3, wherein: The load (2) is a weight, and the lower clamp is a dovetail clamp connected with the upper end of the weight.

5. The tendon cross-sectional area measuring device of claim 1, wherein: The lowering device (4) comprises a linear driving module (41), a cantilever (42) and an upper clamp (43). The linear driving module (41) is vertically arranged on the base (100) and used for controlling the up-and-down sliding of the cantilever (42). The upper clamp (43) is arranged below the cantilever (42).

6. The tendon cross-sectional area measuring device of claim 1, wherein: The upper clamp (43) comprises a sliding seat (431), a sliding rail (432), a bidirectional screw rod (433), a clamping jaw (434) and a knob (435). The sliding rail (432) is arranged on the sliding seat (431), and the sliding seat (431) is installed below the cantilever (42). The bidirectional screw rod (433) is rotatably arranged on the sliding seat (431). Two clamping jaws (434) are respectively arranged at the two ends of the bidirectional screw rod (433) and are in sliding connection with the sliding rail (432). The knob (435) is coaxially connected with the bidirectional screw rod (433).

7. The tendon cross-sectional area measuring device of claim 1, wherein: The device further comprises leveling feet (5), an attitude instrument (6) and buffer supporting columns (7). The buffer supporting columns (7) are arranged between the measuring cylinder (1) and the base (100). The attitude instrument (6) is arranged on the base (100) and used for measuring the angle between the base (100) and a horizontal plane.

8. The tendon cross-sectional area measuring device of claim 1, wherein: The device further comprises a display screen (8) used for displaying the liquid level of the physiological saline, the liquid level increment of the physiological saline, the sampling length and the cross-sectional area corresponding to the sampling length.

9. A method of measuring a cross-sectional area of a tendon using the tendon cross-sectional area measuring device according to any one of claims 1 to 8, characterized by: The measuring cylinder (1) is filled with physiological saline. The upper end of the tendon is installed on the lowering device (4), and the load (2) is hung at the lower end of the tendon. The tendon is lowered into the cylinder (1) by the lowering device (4), and the starting point of the tendon is taken as the starting point of the test; The tendon is controlled to descend at a preset speed by the lowering device (4) until the end point of the tendon; The hydraulic pressure value of the physiological saline is detected in real time by the pressure sensor (3); The pressure variable measured by the pressure sensor (3) is converted into the volume variable of the physiological saline by the cross-sectional area measurement module, and the average cross-sectional area of the tendon at the corresponding displacement is obtained based on the corresponding displacement of the load (2); The average cross-sectional area corresponding to each displacement H during the descent of the tendon is taken as the test unit, the displacement H is taken as the abscissa, and the cross-sectional area of the tendon is taken as the ordinate, to obtain a cross-sectional area curve of the tendon, and the lowest point of the curve is the thinnest point of the tendon, which is focused on in the stretching experiment.

10. The tendon cross-sectional area measurement method of claim 9, wherein: The pressure variable measured by the pressure sensor (3) is converted into the volume variable of the physiological saline by the cross-sectional area measurement module, the change in the liquid level is obtained based on the cross-sectional area of the cylinder (1), and the time (t) - liquid level change value (h) graph is drawn based on the numerical value of the liquid level change and the speed of the tendon immersed in the liquid, so as to obtain the smallest slope point as the thinnest point of the tendon, calculate the cross-sectional area of the point, and the average cross-sectional area within 5mm above and below the point, and focus on the change of the point in the stretching experiment.

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