Abstract:
The invention relates to an aid for relaxing the extensor musculature in the forearm. The invention also relates to a method for relaxing the extensor musculature in the forearm. The aid and the method mentioned according to the invention are both based on the principle of the flexor-extensor antagonism and can be used for physiologically relaxing an extensor musculature.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to an aid for relaxing the extensor musculature in the forearm.  
           [0002]    The invention also relates to a method for relaxing the extensor musculature in the forearm.  
         SUMMARY OF THE INVENTION  
         [0003]    The aid and method according to the invention are both based on the principle of the flexor-extensor antagonism and can be used for physiologically relaxing an extensor musculature. This extensor musculature is an extensor muscle, i.e. an extensor in the forearm which is connected to the lateral epicondyle. The extensor musculature is in antagonistic action with the flexor musculature.  
           [0004]    The object of the invention is to relax the extensor musculature in the forearm. To this end, an aid according to the invention is characterized in that it is provided with a first body, a second body and at least one hinge joint hinging the first and the second body together, the first body being arranged to be secured to a forearm while the second body extends from the hinge to a palm of the hand belonging to the forearm, the aid being further provided with resilient means which, in use, generate a moment of force between the first and second body such that the second body, hinging relative to the first body, presses against the palm of the hand in a direction directed towards the upper side of the hand belonging to the palm. In the forearm to which the aid is secured, a wearer of the above-mentioned aid will experience a moment of force equivalent to a moment of force which is created by flexing the extensor musculature. As a result, the flexor musculature will be flexed. The extensor musculature is thereby physiologically relaxed. Relaxation of the extensor musculature is one of the possible applications of the invention which can be of interest in the case of injured extensor musculature. An example of an injured extensor musculature is a so-called tennis elbow. Such as injury occurs frequently. This injury results in pain stimuli coming from the origin of the extensor musculature at the elbow. This origin is the epicondyle. Physiological relaxation of the extensor musculature reduces the pain stimuli and promotes recovery of the injury. Heretofore, in case of an injury to the extensor musculature, use is made of straps being tied around the forearm. Although these straps provide some support to the extensor musculature, the extensor musculature is thereby hardly relaxed, if at all.  
           [0005]    Preferably, the first body is provided with a first channel-shaped member of a rigid material. In particular, the first channel-shaped member is arranged to embrace, in use, at least a part of an underside of the forearm. It has been found that with this variant, attachment to the forearm is best to generate the desired moment of force.  
           [0006]    Further, it is preferred that the second body is provided with a second channel-shaped member of a rigid material.  
           [0007]    In particular, the second channel-shaped member is arranged to abut, during use, against at least a part of an inside of the hand situated between the index finger and the little finger.  
           [0008]    According to a highly advanced embodiment of the aid according to the invention, the first channel-shaped member is provided with a first and second side wall situated opposite each other, the second channel-shaped member is provided with a first and second side wall situated opposite each other, and the at least one hinge comprises a first and second hinge, the first hinge hinging the first side walls together around a rotation axis and the second hinge hinging the second side walls together around the rotation axis. It has been found that such an aid can be very easily worn without the user suffering much hindrance. Also, it is hardly, if at all, visible that the user is wearing the aid. Moreover, clothing can be worn in the normal manner.  
           [0009]    In particular, the first hinge is provided with a first metal resilient bar-shaped member having a first and second end which are connected to the first side walls of the first and second channel-shaped member, respectively, and the second hinge is provided with a second metal resilient bar-shaped member having a first and second end connected to the second side walls of the first and second channel-shaped member, respectively, the first and second bar-shaped members forming the resilient means.  
           [0010]    A particular advantage of this embodiment is that the hinges can work, without friction and noise.  
           [0011]    Due to the resilient means and the hinge being integrated in the first and second metal, flexible bar-shaped member, the aid can be designed to be very compact, which, again, offers great advantages for a user when wearing the aid.  
           [0012]    According to a highly advanced embodiment, the resilient means are provided with memory metal. Such a material has a number of very special properties. For instance, large elastic deformation is possible. Further, the material comprises a very low rigidity modulus when the material stress reaches the so-called plateau stress. Such an arrangement has the advantage that with a selected initial moment of force in a particular position of the hand relative to the arm, the moment of force will change only slightly with an increasing or decreasing angle of bend. This is caused by the relatively low spring constant. As a result of all this, a substantially constant flexiforce, that is, moment of force is exerted on the hand, independently of the position the hand takes around the wrist joint relative to the forearm.  
           [0013]    In particular, the first and second bar-shaped member are manufactured from, the memory metal.  
           [0014]    Preferably, the memory metal comprises a memory alloy in austenitic condition. As a result of all this, the first and the second bar-shaped member can have a length varying between 40 mm and 120 mm. The first and the second bar-shaped member can have a diameter of 0.5 mm to 2 mm. Further, the above-mentioned advantage of the substantially constant moment of force is present.  
           [0015]    A favorable embodiment of the aid according to the invention is characterized in that the first body is substantially tubular and is provided with a channel-shaped member of a rigid material, and a first elastically adjustable strap connected to the channel-shaped member, the channel-shaped member being arranged to embrace, in use, at least a part of an upper side of the forearm while the first strap bridges an open longitudinal-side of the channel-shaped-member, thereby passing over at least a part of the underside of the forearm. With the first, elastically adjustable strap, provided to that end with, for instance, a Velcro tape closure or clasps, the first body can be secured to the forearm. The second body of the aid should be connected to the hand of the forearm. To this end, a further elaborated embodiment according to the invention is characterized in that the second body is arranged to embrace the part of the hand situated between the fingers and the thumb. Preferably, the hand is then only party covered, so that it can continue to perform its gripping functions substantially completely. In a special embodiment, the aid is further characterized in that the second body has a substantially tubular design and is manufactured from a rigid material.  
           [0016]    An advantageous embodiment of the aid according to the invention is characterized in that the resilient means are provided with a resilient body having a first and second end between which, when they are moved further away from each other, a spring force increases, a first end being connected to the first body at a position which, in use, lies at an upper side of the forearm and the second end being connected to the second body at a position which, in use, is situated at an upper side of the hand. The resilient body applies a moment of force between the first and the second body, allowing the second body to hinge relative to the first body about the hinge situated between the two latter bodies. A particularly advantageous embodiment according to the invention is characterized in that the first body is provided with a first and second side wall situated opposite each other, the second body is provided with a first and second side wall situated apposite each other and the at least one hinge comprises a first and second hinge, the first hinge hinging the first side walls together around a rotation axis and the second hinging the second side walls together around the rotation axis. In a particular embodiment, the aid is further characterized in that the first and second hinge are each provided with the resilient means which press the first and second body relative to each other about the rotation axis to a predetermined position in which the first and second body include a predetermined angle, which angle is in a plane directed perpendicularly to the rotation axis.  
           [0017]    The invention also provides a method for relaxing the extensor musculature through the principle of the flexor-extensor antagonism, wherein, by the exertion of forces on at least three pressure points on a forearm, the wrist of the forearm and the palm of the hand of the forearm, respectively, a moment of force is applied to the palm of the hand, such that the flexor musculature in the forearm must be flexed, as a result of which, due to the antagonism between the flexor musculature and the extensor musculature in the forearm, the extensor musculature is relaxed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    The invention will presently be further elucidated with reference to the drawing. In the drawing:  
         [0019]    [0019]FIG. 1 schematically shows the principle of the invention for relaxing the extensor musculature by using at least three pressure points;  
         [0020]    [0020]FIG. 2 a  shows a schematic overview of relevant forces and moments of force in the forearm without external force;  
         [0021]    [0021]FIG. 2 b  shows a schematic overview of relevant forces and moments of force in the forearm with an external force of an aid according to the invention;  
         [0022]    [0022]FIG. 3 a  schematically shows a side view of a first possible practical embodiment of an aid according to the invention;  
         [0023]    [0023]FIG. 3 b  shows a perspective representation of the aid according to FIG. 3 a;    
         [0024]    [0024]FIG. 4 shows a first alternative embodiment of the aid according to the invention;  
         [0025]    [0025]FIG. 5 shows a second alternative embodiment of the aid according to the invention;  
         [0026]    [0026]FIG. 6 a  shows a third alternative embodiment of the aid according to the invention in a condition in which it is worn; and  
         [0027]    [0027]FIG. 6 b  shows the aid of FIG. 6 a  in a relaxed condition when, it is not worn. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0028]    [0028]FIG. 1 shows a forearm  2  on which three pressure points  4 ,  6  and  8  are indicated. The first pressure point  4  is located on the underside of the forearm, the second pressure point  6  is located on the wrist of the forearm and the third pressure point  8  lies against the palm of the hand of the hand  10 . By applying forces to these at least three pressure points, a force component F aid    12  is applied to the palm of the hand, such that the hand  10  is pressed in a direction towards the upper side of the hand belonging to the palm of the hand. This is further elucidated in FIG. 3 a . In FIG. 3 a , an aid  13  is shown which is secured to a forearm  2 . The flexor musculature  14  (flexor muscle) is a flexor which is in antagonistic action with the extensor musculature  16 . The extensor musculature  16  (extensor muscle) is an extensor which is connected to the lateral epicondyle  17  in the elbow. The force component F aid    12  has as a result that flexor musculature  14  in the forearm  2  has to be flexed. As a result of the antagonistic action, which will be further elucidated below, the extensor musculature  16  will be physiologically relaxed. This relaxation is particularly important in case the extensor musculature is injured. A common injury of the extensor musculature is the so-called “tennis elbow”. This injury results in pain stimuli which come from the origin of the extensor musculature in the elbow (epicondyle)  17 . The physiological relaxation of the extensor Musculature according to the invention promotes recovery.  
         [0029]    [0029]FIGS. 2 a  and  2   b  give a schematic overview of relevant forces and moments of force in the forearm  2 . In FIG. 2 a , no external force is incorporated. FIG. 2 b  does involve an external force, which is exerted, for instance, by an aid according to the invention.  
         [0030]    [0030]FIG. 2 a  is a schematic overview of a forearm  2  with an associated hand  10 . It is schematically indicated how a force F ext    18  is exerted by the extensor musculature, and a force F flex    20  is exerted by the flexor musculature on the hand  10 . There are no external forces working on the forearm. The force F ext    18  yields a force component, F ext  ⊥  122  perpendicular to the hand  10  relative to the wrist joint  24 , which makes the hand  10  hinge in the direction of rotation R. The force Flex  20  yields a force component F ext  ⊥  26  perpendicular to the hand  10 , relative to the wrist joint  24 , which makes the hand  10  hinge in a direction opposite to the direction of rotation R. FIG. 2 b  shows the result of the application of an external force component F aid    12  to the hand  10  (this force component is, for instance, generated by an aid according to the invention). To control the hand  10 , there must almost be a near balance of moments of force relative to the joint  24 . What applies here is that the flexor musculature should apply a moment of force (F flex , ™*R 14 )  26  which is almost equal to but opposite to the sum of the moments of force (F ext , ⊥*R 2 )  22  and (F aid *R 3 )  12 . (Wherein R 1 , R 2  and R 3  are the respective arms of the force components F flex , ⊥, F ext , ⊥ and F aid , relative to the wrist joint  24 ). From the foregoing, it follows that the force component F ext    22  generated by the extensor musculature will be smaller than in the case where the force component F aid    12  is not presented. The force F ext    18  which is exerted by the extensor musculature will also be smaller. In this way, the extensor musculature is physiologically relaxed through the flexor-extensor antagonism.  
         [0031]    [0031]FIG. 3 a  shows the forearm  2  to which a possible practical embodiment of an aid  13  according to the invention is secured. The aid  13  for relaxing the extensor musculature  16  in the forearm is provided with a first body  30  and a second body  32 . The aid further comprises at least one hinge joint  34  which hingedly connects the first aid second body. In this example, two hinges are involved. The first body  30  is arranged to be secured to a forearm  2  while the second body  32  extends from the hinge  34  to a palm of the hand  36  belonging to the forearm  2 . Additionally, the aid is provided with resilient means  38  which, in use, generate a moment of force between the first and second body relative to the hinge (and hence relative to the rotation axis of the two bodies), such that the second body  32 , hinging relative to the first body  30 , presses against the palm of the hand  36  in a direction directed towards the upper side of the hand belonging to the palm (this direction is indicated in FIG. 2 b  with the vector D 12 ).  
         [0032]    The aid  13  in FIG. 3 a  comprises a first body  30  which is of substantially tubular design and is provided with a channel-shaped member  40  of a rigid material and a first elastically adjustable strap  42  which is connected to the channel-shaped member  40 . The channel-shaped member  40  is arranged to embrace, in use, at least a part of an upper side of the forearm  2 , while the first strap  42  bridges an open longitudinal side of the channel-shaped member, thereby passing over at least a part of an underside of the forearm. The first strap  42  can be provided with a fastening mechanism comprising, for instance, Velcro tape or clasps.  
         [0033]    The second body  32  of the aid  13  is arranged to embrace the part of the hand  10  situated between the index finger and the little finger. According to the embodiment of FIG. 3 a , the second body  32  is substantially tubular and made of a rigid material. The hand  10  is preferably not completely covered, so that the hand is restricted as little as possible in its gripping function by the aid  13  secured to the forearm  2 . Further, the resilient means are designed as a resilient body  38 . This resilient body  38  comprises a first and a second end between which a spring force increases when they are moved further away from each other. The resilient body  38  can be an elongate elastic material (such as an elastic). The first end of the resilient body  38  is attached to the first body  30 , at a position  44 , which, in use, lies at an upper side of the forearm. The second end is connected with the second body  32  at a position  46 , which, in use, lies at an upper side of the hand. In a further elaborated embodiment according to FIG. 3 a , the first body  30  is provided with a first side wall  48  and a second side wall  50  which are situated opposite each other (see FIG. 3 b ). The second body  32  is provided with a first side wall  49  and an opposite second side wall  51 . The aid  13  here comprises a first hinge  34  and a second hinge  35  which are situated opposite each other on either side of the wrist. The first hinge  34  hingedly connects the first side wall  48  of the first body  30  with the first side wall  49  of the second body  32  about a rotation axis (this rotation axis is substantially perpendicular to the plane of the drawing of FIG. 3 a ). The second hinge  35  hingedly connects the second side wall  50  of the first body  30  to the second side wall  51  of the second body about the rotation axis mentioned.  
         [0034]    In FIG. 4, a first alternative embodiment of an aid according to the invention is shown. In this embodiment of the aid  13 , the first body  30  is of a substantially tubular design and manufactured from a rigid material. The tubular first body  30  is arranged to embrace a forearm. The second body  32  is arranged to embrace the part of the hand of the forearm situated between the index finger and the little finger, this second body  32  being of substantially tubular design and manufactured from a rigid material. In a further elaborated embodiment accosting to FIG. 4, the first body  30  is provided with a first side wall  48  and a second side wall  50 , situated opposite each other. The second body  32  is provided with a first side wall  49  and an opposite second side wall  51 . The aid  13  here comprises a first hinge  52  and a second hinge which are situated opposite each other on either side of the arm. The first hinge  52  hingedly connects the first side wall  48  of the first body  30  to the first side wall  49  of the second body  32  about a rotation axis. The rotation axis is indicated in FIG. 4 with reference numeral  55 . The second hinge hingedly connects the second side wall  50  of the first body  30  to the second side wall  51  of the second body  32  about the rotation axis mentioned. The aid  13  further comprises resilient paeans which are provided with a resilient body  38  having a first and second end between which a spring force increases when they are moved-further away from each other. The first end of the resilient body  38  is attached to the first body at a position  44  which, in use, lies at an upper side of the forearm, and the second end is connected to the second body at a position  46  which, in use, lies at an upper side of the hand.  
         [0035]    In FIG. 5, a second alternative embodiment of the aid  13  according to the invention is given. Here, the first body  30  of the aid  13  is of a substantially tubular design and is provided with a channel-shaped member  40  of a rigid material and a flexible strap  56 . The channel-shaped member  40  is connected to the first flexible strap  56  and is arranged to embrace, in use, at least a, part of an underside of a forearm. The first strap  56  bridges an open, longitudinal side of the channel-shaped member  40  and passes over at least a part of an upper side of the forearm. The second body is arranged to embrace the part of the hand situated between the index finger and the little finger, to which send the second body is of a substantially tubular design. Further, the second body is provided with a pressure member  58  of a rigid material and a flexible second strap  60  which is connected to the pressure member  58 . The pressure member  58  is arranged to abut, in use, at least partly, against the palm of the hand, while the second strap  60  passes over the back of the hand. Preferably, the first and second strap are provided with a fastening mechanism comprising, for instance, Velcro tape or clasps. In a further elaborated embodiment according to FIG. 5, the first body  30  is provided with a first side wall  48  and a second side wall  50 , situated opposite each other. The second body  32  is provided, with a first side wall  49  and an opposite, second side wall  51 . The aid here comprises a first hinge  52  and a second hinge  53 , situated opposite each other. The fist hinge  52  hingedly connects the first side wall  48  of the first body  30  to the first side wall  49  of the second body around a rotation axis. The second hinge  53  hingedly connects the second side wall  50  of the first body  30  to the second side wall  51  of the second body  32  around the rotation axis  55 . In this embodiment, the first hinge  52  and the second hinge are each provided with resilient means which press the first body  30  and the second body  32  relative to each other about the rotation axis  55  to a predetermined position in which the first and second body include a predetermined angle α. This angle α is in a plane perpendicular to the rotation axis  55 . In FIG. 5, this angle α is schematically indicated by means of two dotted lines. These dotted lines indicate the positions of the first body  30  and the second body  32  of the aid  13  relative to each other when the aid  13  is in the initial or rest position. (In FIG. 5, the aid  13  is not represented in the position of rest. The position represented in FIG. 5 can be achieved from the position of rest by applying an external moment of force between the first body and the second body).  
         [0036]    In FIGS. 6 a  and  6   b , a third alternative embodiment of an aid according to the invention is shown, in which parts corresponding to the preceding figures are provided with the same reference numerals. In the device according to FIGS. 6 a  and  6   b , the first body  30  is provided with a first channel-shaped member  40 . The channel-shaped member is further provided with a first side wall  48  and a second side wall  50 . In the first and second side wall  48 ,  50 , slotted openings  60 ,  62  are provided. Through these openings, a strap  63  can be laced, such that it extends over an upper side of a forearm of a user for securing the first body  30  to the forearm. For closing the strap in a loop-shape, the ends of the strap can, for instance, be provided with Velcro tape.  
         [0037]    In this example, the second body  32  is likewise provided with a second channel-shaped member  41 . The second channel-shaped member  41  is provided with two side walls  49 ,  51 , situated opposite each other. The second body also comprises a pressure member  58  arranged to lie, in use, at least partly against the palm of the hand. In particular, this part of the second channel-shaped member extends, in use, between a part of the inside of the hand situated between the index finger and the little finger. This part of the channel-shaped member lies against this part of the hand and presses against it. The aid further comprises a first and second hinge  52 ,  53 , the first binge  52  hingedly connecting the first side walls  48 ,  49  to each other and the second hinge  63  hingedly connecting the two side walls  50 ,  51  to each other. In this example, the first side walls  48 ,  49  and the second side walls  50 ,  51  are pivotally connected to each other around an imaginary rotation axis  55 .  
         [0038]    The first hinge  52  is provided with a first metal resilient bar-shaped member  52  having a first and second end  70 ,  72  which are connected-to the first side wall  48  and the second side wall  49 , respectively. The second hinge is likewise provided with a, in this case second, metal resilient liar-shaped member  53  having a first and second end  70 ,  72 , which are connected to the second side walls  50 ,  51 , respectively. The first and second metal bar-shaped members  52 ,  53  also form the earlier-mentioned resilient means.  
         [0039]    In the example, the first and second bar-shaped member  52 ,  5  are manufactured from memory metal. In this example, the memory metal comprises a memory alloy in austenitic condition.  
         [0040]    When the aid is not in use and the resilient means  52 ,  53  are relaxed, the aid is in a condition as shown its FIG. 6 b . In use, the aid is in a condition according to FIG. 6 a  when the hand is extended around the wrist joint in line with the forearm. The moment of force referred to is then exerted on the hand.  
         [0041]    The memory metal has as a property that when, for instance, taking as a starting point the condition in FIG. 6 a , the resilient means  52 ,  53  are bent in the direction of rotation R as shown in FIG. 3 a , or, conversely, are bent in a direction of rotation opposite to the direction R as shown in FIG. 3 a , the moment of force exerted on the palm of the hand will change little. The material chosen has the properties specific for memory metal in austenitic form, i.e. large elastic deformation is possible (8% or more, so-called superelasticity). Further, a very low modulus of stiffness is involved when the material stress reaches the so-called plateau stress.  
         [0042]    Starting from the condition in FIG. 6 a , when the aid is worn by a user, the moment of force will only decrease slowly, that is, little, when the second body is moved in the direction R, as shown in FIG. 3 a  relative to the first body, or when the second body is moved relative to the first body in a direction opposite to the direction R of FIG. 3 a . It follows that a fairly constant flexiforce (moment of force) is exerted on the hand which is reasonably independent of the position, i.e. the position the hand takes relative to the forearm.  
         [0043]    Furthermore, lax particular with the above-mentioned choice of material, the first and second bar-shaped member can have a length of 40 mm to 120 mm. Further, the first and the second bar-shaped member can have a diameter of 0.5 to 2 mm.  
         [0044]    The first body  30  can be manufactured from, for instance, a semi-rigid plastic material which has been conformed to the forearm of the patient by heating. The second body can also be manufactured from a semi-rigid plastic which has been conformed to the hand of the patient by heating.  
         [0045]    In the example of FIG. 6 a , mention is made, of a first channel-shaped member  44  provided with the flexible strap  63 . The flexible strap  63  and the channel-shaped member  40  together form a tubular member which can embrace the forearm completely. In the present patent application, the term channel-shaped member therefore encompasses a first body of a tubular design. In particular, also the strap  63  can be replaced with the same material as that from which the channel-shaped member  40  is manufactured. In that case, a tube made in one piece from plastic as shown in FIG. 4 is obtained. What holds true for the first body  30 , also holds true, by analogy, for the second body  32 , which, accordingly, can also be of tubular design and the term channel-shaped, in this context, encompasses a tubular shape.  
         [0046]    It is also conceivable that the first body  30  has a tubular design, wherein, in the first body at its upper side, i.e. the side which, in use, is on top of the forearm, a cut  80  is provided. This arrangement is schematically shown in FIG. 6 b . Parts  82 ,  84  can then be bent away from each other to enlarge the cut  80  to position the first body  30  around the arm. The pressure point  6  shown in FIG. 1 is an imaginary pressure point in this example, which is formed in combination by symmetrical forces between the first body and the forearm. Such variants are all understood to fall within the scope of the invention.  
         [0047]    The invention has been described on the basis of a few preferred embodiments, but, as will be evident to the skilled person, many embodiments are possible which also fall within the scope of the invention. It is possible, for instance, to design the aid in all possible combinations of the above described embodiments of the first and the second body of the aid. These embodiments can be realized in different sizes in a version for the left as well as for the right arm. Further, there are various alternatives with which the resilient means can be provided, it being possible, for instance, that the resilient means comprise a leaf spring (resilient means also encompass resilient means causing a rotation to extension, both through pull forces and pressure forces). The resilient means can be incorporated in the hinge.