US20120220904A1 - Apparatus and method for measuring an anatomical angle of a body - Google Patents

Abstract

An apparatus (20) for automatically measuring an anatomical angle of a body, the apparatus (20) comprising aligning means (23) for aligning an axis (22) of the apparatus (20) with anatomical landmarks of the body, sensing means (30) for sensing an orientation of the axis (22) while the axis is aligned with the landmarks, and processing means (40) for processing the sensed orientation. The sensing means (30) comprises a magnetometer (32) and an accelerometer (31), and the aligning means comprises a pair of lasers.

Description

FIELD OF THE INVENTION
• The present invention relates generally to an apparatus and method for measuring an anatomical angle of a body.
• Although the present invention will be described with particular reference to measuring an anatomical angle of a human body, it will nevertheless be appreciated that the invention is not necessarily limited to this use.
BACKGROUND ART
• Goniometers are apparatus which are used by physiotherapists and the like to measure anatomical angles of a body. For example, they are often used to measure the range of angular motion of joints.
• The following patent documents disclose examples of known goniometers as well as other apparatus for measuring angles: U.S. Pat. No. 4,771,548 (Donnery), United States Patent Application Publication No. 2006/0137201 A1 (Dixon, et al.), U.S. Pat. No. 6,469,666 (Tonn), U.S. Pat. No. 7,337,751 (Lopez, et al.), U.S. Pat. No. 4,442,606 (Graham, et al.), U.S. Pat. No. 7,204,030 (Kattar), U.S. Pat. No. 7,293,363 (Emmett L. Parker), United States Patent Application Publication No. 2007/0266579 A1 (Briscoe, et al.), U.S. Pat. No. 5,163,228 (Edwards, et al.), U.S. Pat. No. 4,665,928 (Linial, et al.), U.S. Pat. No. 3,879,136 (Takeda), U.S. Pat. No. 4,665,928 (Linial, et al.), United States Patent Application Publication No. 2003/0226268 A1 (Gibson), U.S. Pat. No. 7,359,750 (Song, et al.), U.S. Pat. No. 5,253,655 (Stone, et al.), and International Patent Application No. PCT/DE1993/000891.
• Many existing goniometers include a pair of aligning arms which are able to pivot relative to each other. In use, each arm is aligned with anatomical landmarks which are adjacent to the body part whose angle is being measured. For example, if a goniometer with arms is used to measure the angle between the upper part of a person's leg and the lower part of their leg, one of the arms of the goniometer will be aligned with landmarks on the upper part of the leg while the other arm is aligned with landmarks on the lower part of the leg. Once the arms have been properly aligned with the upper and lower leg parts, the angle between the arms corresponds to the angle between the leg parts and can be read off an analogue scale of the goniometer.
• Goniometers of the above-described type suffer from the disadvantage that the arms are often not long enough to accurately align them with some anatomical landmarks. When this situation arises, the person using the goniometer will usually use an eye-balling approach to align the arms with the landmarks as best they can. The accuracy of the measurement which is obtained will be reduced if the arms are not properly aligned with the landmarks.
• Although this problem can be overcome by extending the length of the arms (e.g. by making the arms extendable) so that they are able to reach all of the landmarks that they need to be aligned with when making a measurement, doing so would make the arms somewhat of an obstruction to a user and also make them more vulnerable to being broken or bent.
• Measurement inaccuracy can also be introduced by the analogue scale of the goniometer from which the angle measurement is read. This is because the user needs to interpret the reading from the scale. Although some devices include a digital display which can address this problem, the displays tend to be small and difficult to read.
• For various reasons, including those given above, many existing goniometers have poor inter therapist reliability because the variability of readings from one user to another tends to be significant. For example, there can be a 5-10 degree variance between different users. Similarly, many existing goniometers have poor intra therapist reliability because the variability of readings from the same user tends to be significant. As a consequence, measurements obtained from such goniometers are generally not taken seriously.
• The inaccuracy and variance of readings obtained from existing goniometers can have significant negative consequences. For example, if a post-operative patient who has had a joint operated on must gain a certain amount of range of motion in that joint before they are able to be discharged from hospital, and if a therapist uses a goniometer to measure the range of motion of the joint to determine whether or not the patient has gained the required amount of motion, the date on which the patient is discharged will be unnecessarily delayed if the patient does have the required range of motion but, due to an inaccurate measurement obtained from the goniometer, the measured range indicates that they do not have the required range. An unnecessary delay in the patient being discharged means that the patient will needlessly be occupying a hospital bed which should be made available to someone else.
• Another problem with many existing goniometers is that a user often needs to operate them with both of their hands. This means that while they are performing a measurement with such a device they do not have a hand available to assist the person on whom they are performing the measurement, or to write down the measurement which is obtained from the device.
• Furthermore, many existing goniometers (particularly those which have aligning arms) are quite bulky. This bulkiness can contribute to the need for users to operate them with both hands.
• Existing goniometers which have short aligning arms and/or analogue scales can also be time-consuming to use, particularly if an accurate measurement is required. This is because it can take time to properly align the arms with landmarks that the arms cannot reach, and because it can take time to properly read the scale.
• In addition, at present, different sized goniometers are required to obtain measurements of different sized joints. A large goniometer is required in order to take measurements for the hip and other large joints. A small goniometer is required in order to take measurements of medium size joints and also to take measurements on the pediatric population. A finger joint goniometer is required in order to measure the angle of finger joints.
• It is against this background that the present invention has been developed.
SUMMARY OF THE INVENTION
• It is an object of the present invention to overcome, or at least ameliorate, one or more of the deficiencies of the prior art mentioned above, or to provide the consumer with a useful or commercial choice.
• Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, a preferred embodiment of the present invention is disclosed.
• According to a first broad aspect of the present invention, there is provided an apparatus for measuring an anatomical angle of a body, the apparatus comprising aligning means for aligning an axis of the apparatus with anatomical landmarks of the body, sensing means for sensing an orientation of the axis while the axis is aligned with the landmarks, and processing means for processing the sensed orientation.
• In one preferred embodiment, the processing means is able to process a sensed first orientation of the axis and a sensed second orientation of the axis to determine an angle between the axis in the sensed first orientation and the axis in the sensed second orientation. Preferably, the apparatus also comprises another aligning means for aligning the axis with anatomical landmarks of the body. Preferably, the sensing means includes a tilt sensor for sensing the tilt of the axis, and a magnetic sensor for sensing the direction of the axis relative to a magnetic field. Preferably, the tilt sensor is able to sense the pitch and roll of the axis. It is preferred that the tilt sensor is an accelerometer. It is also preferred that the magnetic sensor is a magnetometer.
• In another preferred embodiment, the apparatus also comprises another aligning means for aligning another axis of the apparatus with other anatomical landmarks of the body, the aligning means are able to be pivoted relative to each other so as to vary an angle between the axes, and the processing means is able to process the sensed orientation to determine the angle between the axes.
• Preferably, each aligning means is a light source. It is preferred that the light source is a focused or collimated light source. It is particularly preferred that the light source is a laser. For example, the laser may be a solid-state laser.
• Preferably, the processing means is a microprocessor.
• Preferably, the apparatus also comprises a display for displaying the measured angle. It is preferred that the display is a liquid-crystal display (LCD). It is also preferred that the measured angle is displayed in units of degrees.
• Preferably, the apparatus also comprises at least one switch for allowing a user to control the operation of the apparatus. It is preferred that the switch is a pushbutton switch.
• Preferably, the apparatus also comprises storage means for storing instructions or data for processing by the processing means. It is preferred that the storage means is a non-volatile memory.
• Preferably, the apparatus is able to be powered by a battery. It is preferred that the apparatus is able to be powered by a lithium battery.
• It is preferred that the apparatus also comprises a charger for charging the battery. The charger is preferably a Universal Serial Bus (USB) charger.
• Preferably, the apparatus also comprises a housing for housing the aligning means, sensing means and processing means.
• According to a second broad aspect of the present invention, there is provided a method for measuring an anatomical angle of a body, the method comprising the steps of:
• aligning an axis with anatomical landmarks of the body;
• sensing an orientation of the axis while the axis is aligned with the landmarks; and
• processing the sensed orientation.
• In one preferred embodiment, the sensing step includes sensing a first orientation of the axis and sensing a second orientation of the axis, and the processing step includes processing the first sensed orientation and the second sensed orientation to determine an angle between the axis in the sensed first orientation and the axis in the sensed second orientation. Preferably, each orientation is sensed by sensing the tilt of the axis and the direction of the axis relative to a magnetic field. It is preferred that the tilt of the axis is sensed by sensing the pitch and roll of the axis.
• In another preferred embodiment, the method also comprises the step of aligning another axis with other anatomical landmarks of the body by varying an angle between the axes, and the processing step includes processing the sensed orientation to determine the angle between the axes.
• Preferably, each aligning step includes aligning a light beam with the landmarks. It is preferred that the light beam is a collimated light beam. It is particularly preferred that the light beam is a laser beam.
• Preferably, the method also comprises the step of displaying the measured angle.
BRIEF DESCRIPTION OF THE DRAWINGS
• In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which:
• FIG. 1 is a schematic block diagram of an apparatus according to a first preferred embodiment of the present invention when a battery for powering the apparatus is being charged from an external supply of electricity;
• FIG. 2 is a front perspective view of the apparatus according to the first preferred embodiment of the present invention;
• FIG. 3 is a rear elevation of the apparatus illustrated inFIG. 2;
• FIG. 4 depicts the printed circuit board and display of the apparatus illustrated inFIG. 2 after pressing both switches of the apparatus;
• FIG. 5 depicts the printed circuit board and display after both switches are pressed again;
• FIG. 6 depicts the printed circuit board and display after rotating the apparatus and then pressing both switches again;
• FIG. 7 depicts the printed circuit board and display after again pressing both switches;
• FIG. 8 is a flowchart of a method of operating the apparatus illustrated inFIGS. 1 to 7;
• FIG. 9 depicts an apparatus according to a second preferred embodiment of the present invention being used to measure an anatomical angle at a person's knee joint;
• FIG. 10 depicts an apparatus according to a third preferred embodiment of the present invention when the lasers of the apparatus are activated;
• FIG. 11 depicts the three main steps in operating the apparatus illustrated inFIG. 10 to measure an anatomical angle at a person's knee joint;
• FIG. 12 is a schematic block diagram of an apparatus according to a fourth preferred embodiment of the present invention;
• FIG. 13 is a front elevation of the apparatus according to the fourth preferred embodiment of the present invention; and
• FIG. 14 is a flowchart of a method of operating the apparatus illustrated inFIGS. 12 and 13.
BEST MODE(S) FOR CARRYING OUT THE INVENTION
• In the figures, like features of the described preferred embodiments of the present invention have been referenced with like reference numerals.
• Referring toFIGS. 1 to 4, there is depicted anapparatus20 according to a first preferred embodiment of the present invention.Apparatus20 is for measuring an anatomical angle of a body such as a human body. Apparatus which are used for this purpose are usually referred to as goniometers by physiotherapists and the like.
• Apparatus20 includes a pair of aligning or alignment means that are each in the form of a solid-state laser23.Lasers23, which are diametrically opposite each other, are for aligning anaxis22 of theapparatus20 with anatomical landmarks of a body. EachLaser23 is able to emit a respective focused or collimated light beam in the form of a laser beam. Thelasers23 emit the laser beams outwardly from theapparatus20 such that the laser beams are co-linear with each other and theaxis22 of theapparatus20.Lasers23 are preferably low-power lasers so that they do not pose a health risk.
• A sensing means30 of theapparatus20 is a three-dimensional orientation sensor which is able to sense a first orientation of theapparatus20 and, hence, theaxis22 in three dimensions, while theaxis22 is aligned with first anatomical landmarks of the body, and is also able to sense a second orientation of theapparatus20 and, hence, theaxis22 in three dimensions, while theaxis22 is aligned with second anatomical landmarks of the body. Sensing means30 includes a tilt sensor which is in the form of anaccelerometer31, and a magnetic sensor which is in the form of amagnetometer32. Sensing means30 is able to provide stable measurement/sensing of the three-dimensional orientation of an object in space, regardless of the object's orientation.
• Accelerometer31 is able to sense the tilt of theapparatus20 and, hence, theaxis22. In particular,accelerometer31 is able to sense the pitch (i.e. up/down position) and roll (i.e. side to side rocking position) of theapparatus20 and, hence, theaxis22.
• Magnetometer32 is able to sense the yaw (rotational position about a vertical axis) of theapparatus20 and, hence, theaxis22 relative to a magnetic field such as the earth's magnetic field.
• The three-dimensional orientation of theapparatus20 andaxis22, including the pitch, roll and yaw of theapparatus20 andaxis22, which is sensed by the sensing means30 is able to be output by the sensing means30 to a processing means which is in the form of amicroprocessor40. The sensed three-dimensional orientation is output by the sensing means30 in the form of three-dimensional coordinates. In addition to theaccelerometer31 andmagnetometer32, sensing means30 includes interfacing circuitry (not depicted) for interfacing theaccelerometer31 and themagnetometer32 with the microprocessor.Microprocessor40 is able to determine an angle between theaxis22 in the sensed first orientation and theaxis22 in the sensed second orientation by processing the output of the sensing means30 in accordance with computer-readable instructions which are able to be read by themicroprocessor40 and which are stored on storage means which is in the form of anon-volatile memory41.Microprocessor40 is able to output the determined angle to a liquid-crystal display (LCD)42 which is then able to display the angle numerically in units of degrees.LCD42 has a height of 32.41 mm, and a width of 61.82 mm.
• Suitably pressing a pair of pushbutton switches43 enables a user to control the operation of themicroprocessor40 and, hence, theapparatus20.
• Apparatus20 is powered by abattery44. Thebattery44 may for example be a long-life lithium battery. Thebattery44 can be charged by a battery charger such as a Universal Serial Bus (USB)charger45 which is connected to an external charging supply ofelectricity46.
• Lasers23, sensing means30 including theaccelerometer31 andmagnetometer32,microprocessor40,non-volatile memory41,LCD42, and switches43 are all mounted on a printed circuit board (PCB)47.PCB47 is generally circular and has a radius of curvature of 30 mm.PCB47 includes a pair of diametricallyopposite recesses48 for receiving thelasers23. A respective pair of contact prongs49 is secured to thePCB47 and extends into eachrecess48 from thePCB47. Each pair ofcontact prongs49 plugs into a respective slot (not depicted) in a socket (not depicted) of eachlaser23.
• PCB47 is housed within a hollow disc-shapedhousing51.Housing51 includes an opening orwindow52 through which the measured angle which is displayed byLCD42 can be viewed. It also includes a pair ofbuttons53 which are located on diametrically opposite sides of thehousing51. Eachbutton53 operatively engages with arespective switch43 such that theswitch43 is able to be operated by pressing thebutton53. Eachlaser23 is located in thehousing51 such that thelasers23 do not protrude from thehousing51. Also, eachlaser23 is located adjacent to arespective recess54 in thehousing51 such that thehousing51 does not obstruct the laser beams which are emitted by thelasers23.
• With reference toFIGS. 4 to 7, andFIG. 8 which depicts a flowchart of amethod60 of operating theapparatus20, theapparatus20 may be used to measure an anatomical angle of a body joint by firstly performing anactivation step61. Theactivation step61 involves a user pressing bothbuttons53 simultaneously with to activate (i.e. turn on) theapparatus20. Once thebuttons53 have been pressed, both of thelasers23 emit a laser beam, and theLCD42 displays a numeric value in the range of 0-180 degrees. The value which is displayed by theLCD42 depends on the orientation of theapparatus20 andaxis22 at the time, and will change dynamically in response to a change in the orientation of theapparatus20 andaxis22.FIG. 4 depicts theLCD42 displaying a value of 20.0 degrees shortly after activation of theapparatus20.
• The next step of themethod60 isstep62 which is to align the laser beams which are emitted by thelasers23 with first anatomical landmarks of the body which the joint forms part of. The laser beams are aligned with the first anatomical landmarks such that each laser beam intersects a respective one of the first anatomical landmarks. If theapparatus20 is being used to measure a range of angular motion of a joint of a limb, the laser beams are initially aligned with landmarks at a distal end or part of the limb i.e. below the joint. For example, when measuring shoulder flexion when the patient is in supine, theapparatus20 is positioned so that the laser beams align with the landmarks of the greater trochanter of the hip, along the line of the trunk to the mid axilla.
• The landmarks which the laser beams are aligned with may be non-joint landmarks and/or joint landmarks (e.g. landmarks indicating the axis of a joint). The particular landmarks which are used by physiotherapists and the like to measure anatomical angles are well-known in the art and will not be described at length here.
• Step63, which followsstep62, involves sensing a first orientation of theapparatus20 andaxis22 with the sensing means30, and then capturing that information with themicroprocessor40. The first orientation of theapparatus20 andaxis22 is the orientation that theapparatus20 andaxis22 have when the laser beams emitted by thelasers23 are aligned with the first anatomical landmarks of the body. Pressing bothbuttons53 simultaneously while the laser beams emitted by thelasers23 are aligned with the first anatomical landmarks causes the first orientation which is sensed by the sensing means30 to be captured by themicroprocessor40.
• Followingstep63, theapparatus20 automatically performsstep64 which is to zero the numeric value which is displayed by theLCD42 so that the LCD will display a value of 0.0 degrees while theapparatus20 andaxis22 are in the first orientation.FIG. 5 depicts theLCD42 displaying a value of 0.0 degrees after the first orientation of theapparatus20 andaxis22 have been detected, and after the numeric value displayed by theLCD42 has been zeroed.
• In other embodiments, the numeric value which is displayed by theLCD42 may be set to zero at the time that theapparatus20 is activated.
• The next step of themethod60 isstep65 which is to align the laser beams which are emitted by thelasers23 with second anatomical landmarks of the body which the joint forms part of. The laser beams are aligned with the second anatomical landmarks such that each laser beam intersects a respective one of the second anatomical landmarks. If theapparatus20 is being used to measure a range of angular motion of a joint of a limb, the laser beams are aligned with landmarks at a proximal end or part of the limb (i.e. above the joint) after movement of the joint. For example, when measuring shoulder flexion, theapparatus20 is positioned so that the laser beams align with the landmarks of the mid axilla to the medial epicondyle on the humerus.
• Step66, which followsstep63 involves sensing a second orientation of theapparatus20 andaxis22, and capturing that information. The second orientation of theapparatus20 andaxis22 is the orientation that theapparatus20 andaxis22 have when the laser beams emitted by thelasers23 are aligned with the second anatomical landmarks of the body. Pressing both buttons simultaneously while the laser beams emitted by thelasers23 are aligned with the second anatomical landmarks causes the second orientation to be captured from the sensing means30 by themicroprocessor40.
• Step67 of themethod60 occurs automatically afterstep66. Instep67, themicroprocessor40 processes the sensed first orientation and the sensed second orientation to determine what the measured anatomical angle of the joint is.
• The sensed first orientation includes a vector A (i.e. Axyz) which is an initial reference position. Vector A is sensed by themagnetometer32, and includes pitch and roll angles which are sensed by theaccelerometer31. The sensed second orientation includes a vector B (i.e. Bxyz) which is a final reference position. Vector B is sensed by themagnetometer32, and includes pitch and roll angles for vector B which are sensed by theaccelerometer31.
• Microprocessor40 processes the sensed first orientation and the sensed second orientation by transposing vector A and Vector B to the horizontal plane so that vector A (i.e. Axyz) becomes vector A′xy, and so that vector B (i.e. Bxyz) becomes vector B′xy. Themicroprocessor40 then determines the angle between transposed vector A′xy and transposed vector B′xy, and this is the angle which is displayed by theLCD42 atstep68. A similar method is used by a compass system disclosed in a published article which is entitled “Applications of Magnetic Sensors for Low Cost Compass Systems”, by Michal J. Caruso of Honeywell, SSEC, and which is incorporated herein it its entirety by reference.
• After determining the anatomical angle of the joint, the next step which is performed isstep68 which involves themicroprocessor40 controlling theLCD42 to display this information numerically and in units of degrees. The measured anatomical angle is displayed to an accuracy of a single decimal place. This information remains display by theLCD42 irrespective of whether or not theapparatus20 is subsequently moved. In addition, thelasers23 are turned off so that they no longer emit laser beams.FIG. 6 depicts theLCD42 displaying a measured angle of 65.0 degrees.
• The next step in the method isstep69 which involves the user pressing bothbuttons53 so that theapparatus20 is deactivated (i.e. turned off).FIG. 7 depicts theblank display42 of theapparatus20 after it has been turned off.
• It will be appreciated that the sensing means30 is not limited to including theaccelerometer31 andmagnetometer32 to sense the orientation of theaxis22 in three-dimensions, and that the sensing means30 could use other devices/instruments to sense the three-dimensional orientation of theaxis22. For example, the sensing means30 could use electrolytic (fluid) based tilt sensors, gimbaled mechanical structures, gyroscopes, magnetic compasses to sense the orientation of theaxis22.
• Theapparatus20 may be used to measure the anatomical angle of small joints (e.g. finger joints) or the small joints of infants and the like in pediatric settings by selecting a small joint mode of operation of the apparatus by suitably pressing thebuttons53. In the small joint mode, only one of thelasers23 is activated.
• Referring toFIG. 9, anapparatus80 according to a second preferred embodiment of the present invention is being used by auser81 to measure an anatomical angle of a patient'sright knee joint82. Apart from some minor cosmetic differences,apparatus80 is identical to theapparatus20.User81 is shown aligninglaser beams83 which are emitted by the lasers (not depicted) of theapparatus80 withanatomical landmarks84,85 of the patient'sright leg86 while holding theapparatus80 in theirright hand87 adjacent to the patient's lowerright leg88. Theapparatus80 is initially placed on the anatomical bone of the lowerright leg88 to allow intersection of thelaser beams83 with the knee joint82 and theproximal landmark84 of theknee82.Laser beams83 are co-linear with anaxis22 of theapparatus80.
• FIG. 10 depicts anapparatus90 according to a third preferred embodiment of the present invention which is also identical to theapparatus20 apart from some minor cosmetic differences. Thelasers23 of theapparatus90 are shown emittinglaser beams83, and theLCD42 of theapparatus90 is shown displaying an angular reading of 126.0 degrees. A degrees symbol ‘° ’ is displayed on theLCD42 at the right-side of the angular reading to make it clear to a person reading theLCD42 that the angular reading displayed thereon is in units of degrees.Laser beams83 are co-linear with anaxis22 of theapparatus90.
• FIG. 11 depicts the three main steps in operating theapparatus90 to measure an anatomical angle at a person's knee joint. Those steps are:
• 1. Activate;
• 2. Calibrate; and
• 3. Calculate.
• In the Activate step, theapparatus90 is activated (i.e. turned on) by pressing thebuttons53. When theapparatus90 is activated, theLCD42 and thelasers23 are activated.
• In the Calibrate step, thelaser beams83 are aligned with landmarks of the lower part of the leg, and thenbuttons53 are pressed again to zero the reading which is displayed by theLCD42.
• In the Calculate step, thelaser beams83 are aligned with landmarks of the upper part of the leg, and thenbuttons53 are pressed again so that theapparatus90 calculates the angle between thelaser beams83 when they are aligned with the landmarks of the lower part of the leg and thelaser beams83 when they are aligned with the landmarks of the upper part of the leg.
• If a user holds down the twobuttons53 for at least5 seconds, a menu (not depicted) is displayed by theLCD42. The menu includes a heading “Instructions forapplication 1, 2, 3 use”, and includes the following items:
• 1. Landmark review
• 2. Small joint mode
• The menu items can be scrolled through by pressing thebuttons53. To scroll up through the menu items, thetopmost button53 is pressed. To scroll down through the menu items, thebottommost button53 is pressed. To select a menu item, the bothbuttons53 are held down for at least5 seconds.
• Selecting menu item 1—Landmark review causes a submenu to be displayed by theLCD42. The submenu includes a list of joints (e.g. shoulder, elbow, wrist, etc.) which can be measured and whose angular measurements can be reviewed.
• Selectingmenu item 2—Small joint mode results in only one of thelasers23 being activated. This means that thelasers23 can work independently of each other. Small joint mode is used when measuring an anatomical angle of a small joint. When measuring an anatomical angle of a small joint (e.g. a finger joint), bothlasers23 are unable to be used in the manner described previously because theapparatus90 is too large and would cover the landmarks which thelaser beams83 need to be aligned with. In the small joint mode, only one of thelasers23 is activated, and thelaser beam83 which it emits is aligned with the landmarks.
• Referring toFIGS. 12 and 13, there is depicted anapparatus100 according to a fourth preferred embodiment of the present invention.Apparatus100 is for measuring an anatomical angle of a body such as a human body. Apparatus which are used for this purpose are usually referred to as goniometers by physiotherapists and the like.
• Apparatus100 includes an aligning or alignment means that are each in the form of a solid-state laser23.Lasers23 are for aligning afirst axis101 of theapparatus100 with first anatomical landmarks of a human body, and for aligning asecond axis22 of theapparatus100 with second anatomical landmarks of the body.Lasers23 are each able to emit a respective focused or collimated light beam in the form of alaser beam83. Thelasers23 emit thelaser beams83 outwardly from theapparatus100 such that one of thelaser beams83 is co-linear with thefirst axis101, and such that theother laser beam83 is co-linear with thesecond axis22.Lasers23 are preferably low-power lasers so that they do not pose a health risk.
• Apparatus100 also includes a hollow disc-shapedhousing51 which is approximately 50 mm in diameter and which includes an innercircular part102 which one of thelasers23 is fixed relative to, and an outercircular part103 which theother laser23 is fixed relative to. Theouter part103 is able to rotate relative to theinner part102 in either a clockwise or an anticlockwise direction as indicated by the arrow ‘A’ inFIG. 13. Thelaser23 which is fixed relative to theinner part102 is thelaser23 which is for aligning thefirst axis101 with first anatomical landmarks of the body, and thelaser23 which is fixed relative to theouter part103 is thelaser23 which is for aligning thesecond axis22 with second anatomical landmarks of the body. The angle between thelasers23 and, hence, theaxes22 and101 can be varied by rotating theouter part103 relative to theinner part102. Theouter part103 can be rotated relative to the inner part through 360 degrees.
• A sensing means30 of theapparatus100 is able to sense an orientation of thesecond axis22 relative to thefirst axis101. In particular, sensing means30 is able to determine the angular orientation of thesecond axis22 relative to thefirst axis101.
• The sensed orientation is able to be output by the sensing means30 to a processing means40 which is in the form of amicroprocessor40.Microprocessor40 is able to determine the angle between thefirst axis101 and thesecond axis22 by processing the sensed orientation which is output by the sensing means30 in accordance with computer-readable instructions which are able to be read by themicroprocessor40 and which are stored on storage means which is in the form of anon-volatile memory41.Microprocessor40 is able to output the determined angle to a liquid-crystal display (LCD)42 which is then able to display the angle numerically in units of degrees. The angle is displayed to the nearest degree.LCD42 can display a maximum angle of 360 degrees and a minimum angle of 0 degrees.
• Apushbutton switch43 enables a user to control the operation of themicroprocessor40 and, hence, theapparatus100.Apparatus100 is powered by abattery44. Thebattery44 may for example be a long-life lithium battery. Thebattery44 can be charged by a battery charger such as a Universal Serial Bus (USB)charger45 which is connected to an external charging supply ofelectricity46.
• Lasers23, sensing means30,microprocessor40,non-volatile memory41,LCD42, and switch43 are all housed within thehousing51.Housing51 includes an opening orwindow52 through which the measured angle which is displayed byLCD42 can be viewed. It also includes abutton53 which is located on the front of thehousing51 adjacent to theLCD42.Button53 operatively engages with theswitch43 of theapparatus100 such that theswitch43 is able to be operated by pressing thebutton53. Although, for clarity, thelasers23 are shown protruding from thehousing51, they may alternatively be located in thehousing51 such that they do not protrude from thehousing51 and such that thehousing51 does not obstruct thelaser beams83 which are emitted by thelasers23.
• With reference toFIGS. 12 and 13, and alsoFIG. 14 which depicts a flowchart of amethod120 of operating theapparatus100, theapparatus100 may be used to measure an anatomical angle of a body joint by firstly performing anactivation step121. Theactivation step121 involves a user pressing thebutton53 to activate (i.e. turn on) theapparatus100. Once thebutton53 has been pressed, thelasers23 emitlaser beams83, and theLCD42 displays a numeric value in the range of 0-360 degrees. The value which is displayed by theLCD42 depends on the orientation of theaxis22 relative to theaxis101 at the time, and will change dynamically if the orientation of theaxis22 relative to theaxis101 is altered by rotating theouter part103 of thehousing51 relative to theinner part102 of the housing. Rotating theouter part103 relative to theinner part102 changes the orientation of theaxis22 relative to theaxis101 by changing the angle between theaxes22,101.
• The next step of themethod120 isstep122 which is to position thehousing51 over the joint so that thelaser beams83 can be aligned with predetermined anatomical landmarks which are located above and below the joint.
• Atstep123 thelaser beam83 which is co-linear with thefirst axis101 is aligned with first anatomical landmarks. Thelaser beam83 is aligned with the first anatomical landmarks such that thelaser beam83 intersects each one of the first anatomical landmarks.
• Atstep124, thelaser beam83 which is co-linear with thesecond axis22 is aligned with second anatomical landmarks. Thelaser beam83 is aligned with the second anatomical landmarks such that thelaser beam83 intersects each one of the second anatomical landmarks.
• Aligning thelaser beams83 with the first and second anatomical landmarks may require adjustment of the angle between theaxes22,101 by suitably rotating theouter part103 of thehousing51 relative to theinner part102 of thehousing51.
• Atstep125, the sensing means30 senses the orientation of thesecond axis22 relative to thefirst axis101 while thoseaxes22,101 are aligned with the second and first anatomical landmarks, respectively. Atstep126, themicroprocessor40 processes the sensed orientation to determine the angle between thefirst axis101 and thesecond axis22 and controls theLCD42 to display the angle between thefirst axis101 and thesecond axis22.
• Atstep128, theapparatus100 is deactivated (i.e. turned off) by pressing thebutton53.
• By employinglasers23 instead of arms or the like as aligning means assists to make the apparatus described above more compact compared to existing goniometers which have long arms for alignment purposes.
• The various apparatus described above may be used to measure the range of motion of an anatomical joint.
• A user may operate the various apparatus described above using only one of their hands. This enables the user to use their free hand to assist a patient if need be, or to record the angular measurement which is obtained using the apparatus.
• Thelasers23 allow the various axes of the apparatus described above to be accurately aligned with anatomical landmarks. This together with the automatic and accurate sensing, processing and display of the orientation of the various axes enables the apparatus to provide an accurate angular measurement which is more likely to be replicated between multiple measurements by the same user or measurements by different users. Consequently, the apparatus has an improved inter rater/therapist reliability and improved intra rater/therapist reliability compared to prior art devices.
• In addition to being able to take accurate measurements which can be repeated by the same or different users, the apparatus are fast and easy to use.
• The apparatus are able to measure anatomical angles irrespective of the orientation of the angle which is to be measured. Thus, it does not matter whether the angle to be measured lies in a horizontal plane, a vertical plane, or something in between. Consequently, the apparatus are able to be used to measure an anatomical angle of a person irrespective of the position of the person or the part of their body being measured.
• The LCDs of the apparatus are sufficiently large to clearly display the angular measurement which is obtained using the apparatus.
• Thebuttons53 may be used to scroll through and select items from a menu which may be displayed by theLCD42. The menu items may relate to configuring or selecting functions that the apparatus is able to perform. For example, thebuttons53 may be used to put the apparatus in to a normal measuring mode wherelaser beams83 are emitted by bothlasers23, the small joint mode discussed earlier, or to select a landmark revision function. TheLCD42 may display instructions for to assist in operating the apparatus.
• Thehousing51 of the apparatus is preferably made from a material such as polycarbonate and aluminum for comfort and migration to the user, as well as for aesthetics and durability of the apparatus.
• Thebattery charger45 is not limited to being a USB battery charger and may be any sort of battery charger.
• Thedisplay42 may be a touch screen which can be used by a user to operate the apparatus. For example, the touch screen may display various options related to the operation of the apparatus, and the user may select any of those options by appropriately touching the touch screen.
• It will be appreciated by those skilled in the art that variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.
• Throughout the specification and claims, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
• Throughout the specification and claims, unless the context requires otherwise, the term “substantially” or “about” will be understood to not be limited to the value for the range qualified by the terms.
• It will be clearly understood that, if a prior art publication is referred to herein, that reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Claims (22)

1. A pocket-sized goniometer having at least a first laser arm and a second laser arm; the goniometer substantially embodied in a housing provided with a digital display for display of anatomical angles.

2. The goniometer ofclaim 1 wherein the goniometer comprises aligning means for aligning an axis of the goniometer with anatomical landmarks of the body,

sensing means for sensing an orientation of the axis of the goniometer while the axis is aligned with the landmarks, and

processing means for processing the sensed orientation.

3. The goniometer ofclaim 1, wherein the processing means is able to process a sensed first orientation of the axis and a sensed second orientation of the axis to determine an angle between the axis in a sensed first orientation and the axis in a sensed second orientation.

4. The goniometer ofclaim 2, wherein the sensing means includes a tilt sensor for sensing the tilt of the axis, and a magnetic sensor for sensing the direction of the axis relative to a magnetic field.

5. The goniometer ofclaim 4, wherein the tilt sensor is able to sense the pitch and roll of the axis.

6. The goniometer ofclaim 4, wherein the tilt sensor is an accelerometer.

7. The goniometer ofclaim 4, wherein the magnetic sensor is a magnetometer.

8. The goniometer ofclaim 3, wherein the goniometer also comprises another aligning means for aligning another axis of the goniometer with other anatomical landmarks of the body, the aligning means are able to be pivoted relative to each other so as to vary an angle between the axes, and the processing means is able to process the sensed orientation to determine the angle between the axes.

9. The goniometer ofclaim 2, wherein each aligning means is a light source.

10. The goniometer ofclaim 9, wherein the light source is a laser.

11. The goniometer ofclaim 1, wherein the goniometer also comprises a display for displaying the measured angle.

12. The goniometer ofclaim 1, wherein the goniometer also comprises at least one switch for allowing a user to control the operation of the goniometer.

13. A method for measuring an anatomical angle of a body, the method comprising the steps of:

aligning an axis of a goniometer with anatomical landmarks of the body;

sensing an orientation of the axis while the axis is aligned with the landmarks; and

processing the sensed orientation to provide a digital display of the angle, and

wherein the goniometer comprises at least a first laser arm and a second laser arm; the goniometer substantially embodied in a housing provided with a digital display for display of the anatomical angle.

14. The method ofclaim 13, wherein the sensing step comprises sensing a first orientation of the axis and sensing a second orientation of the axis; and the processing step comprises, processing the first sensed orientation and the second sensed orientation to determine an angle between the axis in the sensed first orientation and the axis in the sensed second orientation.

15. The method ofclaim 14, wherein each orientation is sensed by sensing the tilt of the axis and the direction of the axis relative to a magnetic field.

16. The method ofclaim 15, wherein the tilt of the axis is sensed by sensing the pitch and roll of the axis.

17. The method ofclaim 13, wherein the method also comprises the step of aligning another axis with other anatomical landmarks of the body by varying an angle between the axes, and the processing step comprises processing the sensed orientation to determine the angle between the axes.

18. The method ofclaim 13, wherein each aligning step comprises aligning a light beam with the landmarks.

19. The method ofclaim 18, wherein the light beam is a laser beam.

20. (canceled)

21. (canceled)

22. (canceled)

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