Abstract:
An adjustable limb support includes a hinged vertical support trough that is movable about a central pivot post and is attached to a pair of hinged support arms, the hinged support arms being horizontally adjustable at one end to allow for vertical height adjustment at the other end. The limb support is configured to be adjustable yet fixable in an infinite number of positions. The limb support is also intended to be radio transparent for use in CT, x-ray and PET applications.

Description:
FIELD OF THE INVENTION 
     This invention relates to a limb supporting device that is intended to be used in conjunction with radiographic diagnostic procedures. More particularly, it relates to an adjustable limb support for use while a patient is undergoing radiological examination wherein the limb support allows for multiple and reproducible elevational and rotational settings and adjustments relative to the limb that is being supported by the holder. It also relates to such a limb support that is generally radiolucent. 
     BACKGROUND OF THE INVENTION 
     Radiological examinations often require a part of a patient&#39;s anatomy to be positioned and remain held in a certain position that is either extremely uncomfortable to the patient, exhausting to the patient or physically impossible for the patient to hold for the duration of the examination. Many methods and devices for positioning limbs and extremities for examination are currently used, from formed pillows to mechanical devices. Generally speaking, devices designed to support parts of the human body in various positions must provide rigid support in addition to providing a comfortable, or at least tolerable, experience for the patient. Devices designed to support parts of the human body must further provide a broad range of adjustability so that they can accommodate a broad range of sizes and shapes of people. It is also desirable to design such devices so that the position of the particular part of the human anatomy being examined can be duplicated or recreated if repeat examination becomes necessary due to poor quality of the radiographic image. 
     For example, the magnetic resonance imaging (“MRI”) study of the human shoulder requires a patient to elevate his or her arm and hold the arm in various positions for the duration of the examination. At the same time, those generally in need of an MRI study may also have some sort of injury to the shoulder and may experience great difficulty holding any position on his or her own for an extended period of time. On the other hand, the MRI machine requires the patient to remain very still in order to capture and produce a high quality image. The device of the present invention is designed to provide a comfortable support mechanism for patients undergoing this type of examination and is also designed to adapt to provide limb support of other types for patients undergoing other similar exams. 
     Accordingly, it is an object of the present invention to provide a limb support for use with an imaging machine. It is another object of the present invention to provide a limb support of the foregoing type that is capable of multiple adjustments. It is yet another object of this invention to provide a limb support of the foregoing type that, while adjustable, is capable of reproducing a limb position setting for radiographic studies. It is still another object of this invention to provide a limb support of the foregoing type that is generally radiolucent and results in improved radiographic imaging. The foregoing and other objects and advantages of the invention will be apparent from the following summary and detailed description. 
     BRIEF SUMMARY OF THE INVENTION 
     The limb support of the present invention consists of a hinged vertical support that permits movement of the subject in the Y-axis, a center pivot post that allows 360-degree rotation in the Z-axis and rotation in the X-axis. One end of the hinged support is firmly mounted to a base. The other end of the hinged support is adjustable along the base to allow vertical adjustment of the subject to be obtained. Together, the supports form an apex at which the hinge is located. The hinge is also the mounting point for a limb support trough. The hinge provides a mounting point for the limb support trough as well as providing a point of pivot and rotation for the limb support trough. 
     The limb support is a “purpose formed” device that is designed to support the limb as well as hold it in position so that an accurate image can be created. Material selection for the entire device is modality specific, with non-magnetic materials required for MRI and X-ray and transparent materials being required for CT, X-ray, and PET. 
     The advantages of the limb support of the present invention are apparent from a brief examination of the device itself. For example, the limb support permits virtually unlimited adjustment in the vertical axis and has excellent rigidity when positioned. Also, the pivoting limb support “matches” the location of the limb for patient comfort. Perhaps even more important is the ability of an experienced technician or radiologist to repeat the patient&#39;s limb position within the MRI machine as closely as possible. As is obvious, the limb support of the present invention is very simple in design. This simplicity in design results in the apparatus having a very high degree of reliability. Also, the apparatus of the present invention is very cost-effective insofar as the limb support is both adjustable and can be changed to accommodate various body parts and positions. Lastly, the apparatus of the present invention is designed to incorporate existing radiolucent materials which will improve image quality and reduce the need for repeat studies. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front and top perspective view of one embodiment of a limb support constructed in accordance with the present invention and showing the support in a fully “down” position. 
     FIG. 2 is a front and top perspective view of the limb support shown in FIG.  1  and showing the support in a somewhat elevated position. 
     FIG. 3 is a front and top perspective view of the limb support embodiment illustrated in FIG.  1  and showing the elements thereof in an exploded spatial relationship. 
     FIG. 4 is a front, top and left side perspective view of the limb support embodiment shown in FIG.  1  and showing a patient&#39;s arm in phantom view in the fully elevated position. 
     FIG. 5 is a front, top and right side perspective view of the limb support embodiment illustrated in FIG.  1  and showing a patient&#39;s leg in phantom view in a somewhat elevated position. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings in detail, wherein like numbered elements correspond to like elements throughout, FIG. 1 is view of one embodiment of the adjustable limb support (generally identified  100 ) constructed in accordance with the present invention. Although illustrated in a particular embodiment for purposes of this detailed description, it is to be understood that alternative embodiments could be devised without deviating from the scope of the disclosure herein. In general, however, the adjustable limb support of the present invention includes four main elements. The first main element is a base  110 , which base  110  provides a stable platform for mounting the second and third main elements, a first scissor arm  130  and a second scissor arm  150 , respectively. The first scissor arm  130  and the second scissor arm  150  are effectively joined together at one end  134 ,  152 , respectively, by means of a top hinge  140 . The top hinge  140  provides an attachment for the fourth main element, a generally U-shaped limb support trough  170 . 
     In more detail, the base  110  of the device  100  of the present invention is in the general shape of an elongated rectangle. In one embodiment of the device  100 , a first mounting plate  120  is secured at a first end  112  of the base  110 . The mounting plate  120  can be secured to the base  110  by using nearly any means of attachment including adhesive, clamp, Velcro® brand fastener, screws or rivets so long as the mounting means does not permit rotation or translation of the mounting plate  120  relative to or with respect to the base  110 . In the embodiment shown in FIG. 1, the base  110  and the first mounting plate  120  each have a cooperating and complementary aperture that aligns to accommodate a locating peg  118  therewithin. Although not shown, it is to be understood that either the base  110  or the mounting plate  120  could feature a series of such apertures to allow adjustability of the first mounting plate  120  with respect to the base  110 . 
     In the illustrated embodiment, the second end  114  of the base  110  features a plurality of regularly spaced apertures  116  disposed in a generally linear pattern. The apertures  116  should be marked such that an operator of the diagnostic equipment can duplicate a patient&#39;s position in successive examinations by reference to such markings. In this manner, the radiologist and the treating physician will be able to compare previous images with more recent images and know that the images are of the same part of the body taken in the same relative position. See FIGS. 4 and 5. 
     The mounting plate  120  provides an attachment and pivot point for the first scissor arm  130 . The first end  132  of the first scissor arm  130  is mounted to a first hinge  122 . This first hinge  122  is attached to the top of the mounting plate  120 . In this fashion, the first hinge  122  permits upward rotation of the first scissor arm  130  with respect to the base  110 . Although shown as a separate component, it is to be understood that the hinge  122 , or any other hinge used in this device  100 , could be a “living hinge” and machined into the adjoining elements between which the hinge  122  is functionally disposed. The second end  134  of the first scissor arm  130  is attached to the top hinge  140 . The top hinge  140  connects the first scissor arm  130  to the second scissor arm  150  and allows rotation of the first scissor arm  130  relative to the second scissor arm  140 . See FIG.  2 . 
     The first end  152  of the second scissor arm  150  is attached to the top hinge  140 . The second end  154  of the second scissor arm  150  is attached to yet another hinge, a sliding hinge  144 . The sliding hinge  144  is attached to a sliding mounting plate  164 . The sliding hinge  144  allows rotation of the second scissor arm  140  relative to the sliding mounting plate  164 . The sliding mounting plate  164  is generally rectangular in shape and moves or “slides” longitudinally along the base  10 . The sliding mounting plate  164  has an aperture  136  of similar size and shape to the apertures  116  defined within that end  114  of the base  110 . A locking peg  138  is provided to secure the sliding mounting plate  164  to the base  110 . In application, and as the sliding mounting plate  164  is moved towards the fixed mounting plate  120 , the apex formed at the point of the top hinge  140  is variably elevated. See FIG.  2 . Conversely, moving the sliding mounting plate  164  away from the fixed mounting plate  120  lowers the apex. Here again, although a peg  138  and a plurality of apertures  116 ,  136  with which it functionally cooperates are shown, it is to be understood that any method of releasable securement could be incorporated by design and still come within the scope and intended purpose of the present invention. 
     With special regard to FIG. 3, an exploded view of the illustrated embodiment of the present invention shows a detailed view of the top hinge  140 . The top hinge  140  may employ a rod  180  that slides through a set of cooperative and co-linear apertures  135 ,  155  defined within each of the first and second scissor arms  130 ,  150 , respectively. Also provided is a central support bracket  190 . The central support bracket  190  provides a perpendicularly oriented aperture (not shown) that is also aligned with and is co-linear to the apertures  135 ,  155  of the first and second scissor arms  130 ,  150  to allow passage of the rod  180  therethrough. Alternatively, the support bracket  190  may simply be mounted on the rod  180  using some type of fastener. As shown, a trough support plate  194  is also provided. The support bracket  190  generally provides a second axial aperture  192  thereby allowing the bracket  190  to receive a pin  200  that is aligned through a trough aperture  172  and a trough plate aperture  196  such that the limb support trough  170  is permitted to rotate 360 degrees. Further, the support bracket  190  permits the limb support trough  170  to be angled as such is desired or required with respect to the first and second scissor arms  130 ,  150 , respectively. See FIG.  2 . The limb support  100  may support a patient&#39;s arm A or leg L as shown in FIGS. 4 and 5, for example. 
     The limb support trough  170  shown is designed to accommodate a wide variety of patients. The limb support  170  may also be purpose-built for specific applications. For example, a shoulder MRI study often requires a patient to hold an arm at a forty-five degree angle outwardly and at a forty-five degree angle upwardly relative to his or her body axis when the patient is laying on his or her back. In a case such as this, a limb support  100  could be readily be adjusted so that the patient&#39;s upper arm is supported and the patient&#39;s lower arm is comfortably held out in front of the patient. Another limb support trough  170  configuration might represent a ninety degree bend to fully support the patient&#39;s arm and forearm. This particular embodiment might also be used for a patient with an injured knee, to hold the knee in a fixed, but comfortable position for imaging. The limb support trough  170  is designed to rotate azimuthally 360° about its axis. It is additionally able to pivot such that it allows the user to adjust the angle of the limb support trough  170  relative to the first  130  and second  150  scissor arms. It is envisioned by the inventors that both the angle of pivot and the degree of rotation of the limb support trough  170  may both be measured from the device and recorded for future reference. The degree of rotation of the limb support trough  170  can be measured using a circular disk with degree markings. This value can then be recorded and the next time the patient is imaged, the operator can reposition the patient precisely as before. The angle of pivot can also be recorded, either from the vertical or relative to either the first  130  or second  140  scissor arms. In the case of both the angle of pivot and the degree of rotation, the inventors also envision using a “memory” type joint. In other words, the joint will be stiff enough such that the weight of the patient&#39;s limb should not cause movement but the joint is at the same time loose enough to permit movement of the limb support when it is moved by the operator. Alternatively, the inventors envision a fixable joint. This type of joint provides greater ease of movement but requires one to tighten a bolt to secure the angle of rotation or pivot of the limb support. 
     The above described parts can be made of nearly any material but a radiolucent material is preferred. Only a radiolucent material will provide clear and accurate images for the person reading the image. 
     With only these above described elements, the inventors have created a new, versatile and unique apparatus for holding a patient&#39;s arm or leg during a diagnostic examination. This new and unique device allows the operator to adjust the patient&#39;s position with six degrees of freedom. The apparatus has nearly infinite vertical adjustment using the first and second scissor arms. Additionally, the device of the present invention allows the limb support 360 degrees of rotation. Further, the angle the limb support makes with respect to the first and second scissor arm can be adjusted. Even more flexibility can be offered through use of removable and interchangeable limb supports. For example, limb supports can be designed to accommodate both arms and legs or to accommodate either an arm or a leg but to adjust and hold the limb in a specified position. 
     Parts List 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Parts List: 
               
             
          
           
               
                   
                 Part Name 
                 Part Number 
               
               
                   
                   
               
               
                   
                 Adjustable limb support 
                 100 
               
               
                   
                 Base 
                 110 
               
               
                   
                 First end of the base 
                 112 
               
               
                   
                 Second end of the base 
                 114 
               
               
                   
                 Apertures in base 
                 116 
               
               
                   
                 Locating peg 
                 118 
               
               
                   
                 First mounting plate 
                 120 
               
               
                   
                 First hinge 
                 122 
               
               
                   
                 First scissor arm 
                 130 
               
               
                   
                 First end of the first scissor arm 
                 132 
               
               
                   
                 Second end of the first scissor arm 
                 134 
               
               
                   
                 Aperture in first scissor arm 
                 135 
               
               
                   
                 Aperture in sliding mounting plate 
                 136 
               
               
                   
                 Locking peg 
                 138 
               
               
                   
                 Top hinge 
                 140 
               
               
                   
                 Sliding hinge 
                 144 
               
               
                   
                 Second scissor arm 
                 150 
               
               
                   
                 First end of the second scissor arm 
                 152 
               
               
                   
                 Second end of the second scissor arm 
                 154 
               
               
                   
                 Aperture in second scissor arm 
                 155 
               
               
                   
                 Sliding mounting plate 
                 164 
               
               
                   
                 Limb support trough 
                 170 
               
               
                   
                 Trough aperture 
                 172 
               
               
                   
                 Rod 
                 180 
               
               
                   
                 Central support bracket 
                 190 
               
               
                   
                 Second axial aperture 
                 192 
               
               
                   
                 Trough plate aperture 
                 196