WO2001075404A1

WO2001075404A1 - Arm volume measurement

Info

Publication number: WO2001075404A1
Application number: PCT/NL2000/000214
Authority: WO
Inventors: Robert Jacobus Damstra; Lourens Jan De Groot
Original assignee: Robert Jacobus Damstra; Lourens Jan De Groot
Priority date: 2000-03-30
Filing date: 2000-03-30
Publication date: 2001-10-11
Also published as: AU3844600A

Abstract

A method for measuring a total volume of a portion of a human arm extending distally from a transverse cross-section of an upper arm portion of the arm, comprising positioning the arm portion to be measured in a measuring vessel having a reference volume (11), providing a measuring substance having a predetermined top level in the vessel, determining a total volume of the measuring substance in the vessel, and determining the volume of the arm portion from the reference volume (11) and the determined volume of the measuring substance.

Description

Arm volume measurement

The invention relates to a method and an apparatus for measuring the volume of a human arm. Volume measurement of a human arm is used in for example medical diagnosis, for example with the diagnosis of lymphatic diseases. Also in non medical applications this measurement is used, for example for determining arm muscle build-up during training. A known method of determining the volume of a human arm consists of measuring the circumference of the arm at a few positions. The results of these measurements are used to look up the approximate volume of the arm in empirical reference tables. Although this method is cheap, quick and causes little hindrance for the person involved, the accuracy of the volume determined with this method is low.

SUMMARY OF THE INVENTION

It is an object of the present invention to measure the volume of a human arm accurately, without using substantially more time or causing substantially more discomfort than in known methods. According to the present invention, this object is achieved by providing a method according to claim 1. By placing the persons arm in a reference volume and filling the reference volume up to a reference level, the volume of the arm can be determined by measuring the amount of measuring substance that was needed to fill the volume up to the reference level. By using a measuring container in which the persons arm is placed, and which container is consecutively filled with a liquid up to a reference level, the volume of the arm can be determined according to the invention by weighing the container and liquid contained therein after removal of the arm. With this method the volume of the arm can be measured accurate and fast with simple means.

By placing the persons arm in a measuring position wherein the elbow is used as a reference point, in particularly with the arm in a bent position, an accurate and repeatable measuring position is achieved. The invention further relates to a measuring device for measuring the volume of an arm of a person according to claim 12.

Particularly advantageous elaborations of the invention are set forth in the dependent claims. Further objects, elaborations, effects and details of the invention appear from the following description, in which reference is made to the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic cross section of a measuring device according to the invention;

Fig. 2 is a perspective view of the measuring device of Fig. 1;

Fig. 3 is a schematic cross section of the measuring device according to Fig. 1 with a patients arm placed in a measuring position inside the device.

DETAILED DESCRIPTION

In Figs. 1 and 2 a measuring device 1 according to the invention is shown. The measuring device 1 comprises a vessel or container 10, the other walls of which form a rectangular box. The container- 10 has an internal measuring volume 11, which is bounded by the outer walls of the container and an internal divider 12. The volume 11 is essentially L-shaped. The vertical leg of the L-shape is defined by the walls of the container and the divider 12, forming an opening 14 that is connected to the measuring volume 11. Near the opening 14 an outflow outlet 15 is provided in the divider

12 that is connected to container 16. The height of the outlet 15 relative to the volume 11 determines a reference level 13. The container 10 is made of a clear material like plastic; because of this clear material the correct measuring position of the arm can be observed visually. Also the test persons acceptance is improved as the test person can see what is going on inside the measuring device. The size of the internal measuring volume 11 up to the reference level 13 has been determined, for example by measurement or calculation.

The volume 11 is further connected to a water pump 20 by means of a tube 21 that is removably connected to the container 10 via a tube coupling The volume 11 is also connected to an outlet tube 50 by means of a valve 51. By opening the valve 51, water contained in the volume 11 can be discharged through the outlet tube 50.

The container 10 is placed on a weigh unit 30 that is place on a sup- port frame 40. The support frame 40 is placed on the ground. The weigh unit 30 is in this example a known load cell that is connected to a measuring unit 31, that converts the electrical signal of the weigh unit 30 into digital weight information.

Before measuring the volume of a human arm, first the container is filled up with water up to the reference level 13. Consequently the weight of the container 10 in fully filled condition is measured using the weigh unit 30. The weight of the container 10 is measured after disconnecting the tubes 21 and 50. The measured full weight is then recorded by the measuring unit 31, after which the tubes 21 and 50 can be reconnected, and the water can be let out of the container 10. After this measurement, the test person places his arm in the container 10, through the opening 14, as shown in fig. 3. The elbow B of the arm rests on the bottom surface of the container 10, while the underarm A extends into the horizontal leg section of the L-shape of the volume 11. With the arm bent in this measuring position with the elbow located on the bottom of the container 10, a precise and repeatable measuring position of the arm is achieved. In this example the position of the elbow is used as a reference position by placing the elbow on a surface, the invention is however not limited to this embodiment. According to the invention any suitable means of positioning the elbow in a reference position can be used, like an elbow rest or an optical position detection device.

When the arm is placed in the reference position, the pump 20 is activated such that water is supplied to the volume 11 of the container 10. Preferably the water is heated to a temperature of 38°C, or another temperature that is pleasant to the touch. The water preferably contains a disinfectant to prevent contamination. The water is supplied to the container 10 until the water level reaches the reference level 13. Once this level is reached, some water will flow through the overflow 15 into the container 16; at this point the pump is stopped immediately so that the water level does not rise above the reference level 13. Water contained in the container 16 can be left in place if the amount is negligible or be removed. The water surface at the reference level 13 intersects the upper arm transversely in cross section; the water reference level 13 thus determines a plane from which the portion of the arm that is measured extends distally.

In this example the reference level detection is performed by a overflow; the invention is not limited to this embodiment. According to the inven- tion other level detection devices can be used like pressure or conduction sensors or optical level detectors. In a further embodiment of the invention the reference level detection device is coupled with the measuring substance supply unit, such that when the detection device detects that the reference level is reached the supply unit is switched off directly. Now the test person removes his arm from the measuring device 1, and the tubes 50 and 21 are disconnected. With the weigh unit 30 the weight of the container 10 including the remaining water is measured. From the already measured full weight of the container the measured weight of the container together with the remaining water is subtracted, yielding the amount of water that has been replaced by the arm. From this amount of water the volume of the arm is now determined from the volume that corresponds with the volume occupied by that amount of water. This yields a very accurate measurement result for the volume of the arm.

Because no water has to be moved from the container to perform the weight measurement, no inaccuracies because of spillage occur.

According to this example the amount of measuring substance, in this case water, is determined by weighing; the invention is however not limited to this embodiment. The invention also relates to any other suitable method of measuring the amount of measuring substance added to the refer- ence volume up to the reference level. The invention for example relates to determining the volume of the measuring substance in the reference volume by measuring the flow of the measuring substance into the reference volume during the filling of the reference volume, by for instance a flow meter. The invention also provides for determining the volume of the measuring substance in the reference volume after removing the arm by letting the measuring substance flow out of the reference volume and determining the amount by means of for example a flow meter or a weighing device.

In this example water is used as measuring substance; the invention is however not limited to this embodiment. According to the invention other measuring substances can be used, like liquids, suspensions, or solids. In case of solids, especially granular solids can be used according to the invention.

Claims

1. A method for measuring a total volume of a portion of a human arm extending distally from a transverse cross-section of an upper arm portion of said arm, comprising: positioning said arm portion to be measured in a measuring vessel having a reference volume (11), providing a measuring substance having a predetermined top level in said vessel, determining a total volume of said measuring substance in said vessel, and determining the volume of said arm portion from said reference volume (11) and said determined volume of said measuring substance.

2. A method according to claim 1, wherein said determination of said volume of said measuring substance in said vessel includes measuring quantities of said measuring substance supplied to said vessel.

3. A method according to claim 1, wherein said determination of said volume of said measuring substance in said vessel includes measuring said volume after removing said arm portion from said vessel.

4. A method according to claim 3, further comprising removing said measuring substance from said vessel.

5. A method according to claim 4, wherein said determination of said volume of said measuring substance in vessel includes measuring a flow of said measuring substance out of said vessel.

6. A method according to claim 4 or 5, wherein said determination of said volume of said measuring substance in said vessel includes quantitatively measuring said measuring substance removed from said vessel.

7. A method according to any one of the preceding claims, wherein said determination of said volume of said measuring substance in said vessel includes measuring the weight of said measuring substance.

8. A method according to claim 7, wherein said measurement of the weight of said measuring substance is carried out while said measuring substance is in said vessel after removal of said arm portion from said vessel.

9. A method according to any of the preceding claims, wherein the positioning of the arm portion to be measured in a measuring position comprises placing an elbow of said arm in a reference position within said vessel.

10. A method according to claim 9, comprising positioning said elbow in abutment with a bottom surface of said vessel.

11. A method according to any of the preceding claims, wherein the positioning the arm portion to be measured in a measuring position comprises bending the arm.

12. A device for measuring a total volume of a portion of a human arm extending distally from a transverse cross-section of an upper arm portion of said arm, comprising: a vessel (10, 11, 12) for receiving said arm portion to be measured, means for determining a predetermined filling level of a measuring substance in said vessel, and a structure for determining a total quantity of a measuring substance in said vessel.

13. A device according to claim 12, wherein said means for filling said vessel up to a predetermined level comprise an overflow (15) that communicates with an internal space (11) of said vessel (10, 11, 12).

14. A device according to claim 12 or 13, wherein said vessel bounds an essentially L-shaped internal space.

15. A device according to any one of claim 12-14, wherein said structure for determining a total quantity of a measuring substance in said vessel comprises a volume measuring device.

16. A device according to any one of claim 12-15, wherein said structure for determining a total quantity of a measuring substance in said vessel comprises a weight measuring device.

17. A device according to any one of claim 12-16, wherein said vessel (10, 11, 12) for receiving said arm portion to be measured is provided with an outlet for measuring substance.

18. A device according to any one of claim 12-17, wherein said structure for determining a total quantity of a measuring substance in said vessel comprises a flow meter.

19. A device according to claim 17, wherein said structure for deter- mining a total quantity of a measuring substance in said vessel communicates with said outlet.

20. A device according to any one of claim 12-19, wherein said vessel (10, 11, 12) for receiving said arm portion to be measured comprises a positioning device for receiving an elbow of said arm.