Patent Description:
Often, when a patient is sedated for a surgery, the patient is supported by and secured to braces or supports coupled to a surgical table. Sometimes, unique supports are provided for a patient's extremities such as arm boards, leg supports, hand boards, stirrups, and boots.

Supports known in the art sometimes secure patients to resist patient movement. The position and orientation of supports is often adjusted during surgery to improve access to a surgical site or to move portions of the patient's body such as bones, muscles, tendons, and ligaments to evaluate the surgical results. In adjusting the positon of a limb, there may be a need to make adjustments with multiple degrees of freedom in order to locate the limb spatially and to adjust an orientation of the limb. It should be understood that movement and adjustment of a position and orientation of a limb may be used to provide access to the limb, or may be used to make adjustments to tissues that are connected to the limb to thereby better position bones, joints, ligaments, tendons and/or muscles for surgical access to any of those tissues or underlying tissues.

In one example, a lithotomy positioning device may be used to facilitate access to a patient's perineum, organs in the pelvic region, rectum, and genitals. In the lithotomy position, a patient is initially positioned in a supine position and the hips are flexed, the legs abducted, and knees flexed. Using a boot stirrup, placing the patient in the correct position requires movement of boot stirrup in abduction while raising the legs and moving the boot to cause flexure of the knees. There may also be a need to rotate the legs to cause movement of the hip joint. All of these positional adjustment are interdependent and movement of the legs to an abducted positon may result in other flexure throughout the leg and hip. As such, a need exists to make an adjustment with multiple degrees of freedom simultaneously to efficiently. However, there may also be times where a single degree of adjustment is appropriate without risk of having other adjustment positions lost so that adjustments of one degree of freedom can be used to achieve a particular adjustment during procedure. With some positioners, there is a need to support multiple components when a positioner is released for adjustment so that the single degree of adjustment is controlled. This can be cumbersome and require caregivers to support the weight of a limb to prevent unwanted movement during the adjustment.

<CIT> discloses a limb support comprises a spar, a limb rest, and a coupler. The spar is configured to be supported from a patient support apparatus and adjustable relative to the patient support and has a longitudinal axis. The coupler includes a release that is selectively actuable to release locking mechanisms to permit adjustment of the limb support relative to the spar.

<CIT> discloses a boot stirrup for use with a surgical table. The boot stirrup includes a support arm, a surgical boot, and a lockable joint coupled to the support arm and the surgical boot. The support arm is configured to couple to a surgical table for movement about a plurality of axes relative to the surgical table. The surgical boot is configured to support and/or immobilize the foot and leg of the patient. The lockable joint is configured to selectively permit movement of the surgical boot relative to the support arm.

The present application discloses one or more of the following features alone or in any combination.

According to a first aspect of the present disclosure, a limb support comprises a spar, a multi-axis coupler supporting the spar, a coupler supported on the spar, and a limb rest supported on the coupler. The multi-axis coupler is releasable to adjust the orientation of the spar relative to a patient support apparatus supporting the limb support. The coupler includes a receiver and a release that is movable relative to the spar. The release is operable to move between a first position wherein the receiver is fixed relative to the spar, second position wherein the receiver is movable relative to the spar about three-axes, and a third position wherein the coupler is movable along the length of the spar. The limb rest is supported on the receiver such that when the release is in the second position, the limb rest is movable relative to the spar to adjust the orientation of a patient's limb relative to the spar and, thereby, a patient support apparatus.

In some embodiments, the limb support further comprises a handle coupled to the release, the handle operable to cause the release to move between the first, second, and third positions.

In some embodiments, the release is biased to the first position.

In some embodiments, movement of the release from the first position reduces the frictional force applied to components within the coupler such that the movement of the release continuously reduces the force necessary to move the limb rest relative to the spar.

In some embodiments, movement of the release from the first position reduces the frictional force between the coupler and the spar such that movement of the release continuously reduces the force necessary to move the coupler relative to the spar.

In some embodiments, the release includes a bias structure that is loaded in the first position to urge components of the coupler together to frictionally lock the coupler with sufficient force to support a patient's limb.

In some embodiments, the release includes a first spar engaging portion and a second spar engaging portion which cooperate to grip the spar, and a bias member acting between the first spar engaging portion and the second spar engaging portion. The bias member may urge the first spar engaging portion and the second spar engaging portion apart. The bias structure of the release may be operable to overcome the bias member when the release is in the first position.

In some embodiments, the bias structure induces a tension load in a tension rod, the tension load acting on components of the coupler to secure the coupler.

In some embodiments, the force applied by the bias structure is reduced as the release is moved from the first position to the third position thereby reducing the tension load in the tension rod.

In some embodiments, the bias structure acts on a first driver urging the first driver toward a second driver, the bias structure urging the drivers together with a first spring force in the first position and the release continuously reducing the spring force to zero as the release is moved from the first position to the third position.

In some embodiments, the drivers are formed to include inclined surfaces that engage mating surfaces of two wedges. The spring force may push the inclined surface of the first driver against the wedges to urge the wedges apart. The wedges may be constrained by second driver and the tension rod such that the spring force is transferred through the drivers and wedges to develop tension in a tension rod. The tension of the tension rod secures the components of the coupler against movement.

In some embodiments, the release further comprises a cam shaft coupled to the handle such that movement of the handle rotates the cam shaft about a longitudinal axis of the cam shaft to move a cam of the cam shaft from the first position to the third position, such that the cam overcomes the spring force of the bias structure in the third position.

In some embodiments, the cam reduces the spring force of the bias structure as the cam moves from the first to the third position. A second position, intermediate the first and third positions, may result in the reduction of the spring force sufficiently to allow a user to adjust the position of the limb rest relative to the coupler while maintaining the coupler in a secured position relative to the spar.

In some embodiments, the release includes a floating spacer that is engaged by the cam shaft. The floating spacer may move relative to the drivers. As the cam moves from the first position to the second position, the floating spacer may engage the bias structure to compress the bias structure. The floating spacer may engage the second driver to move the second driver away from the first driver to effect the release of the coupler by releasing the tension in the tension rod.

In some embodiments, the cam shaft engages a return spring. The return spring may bias the cam shaft to urge the cam shaft toward the first position. The force of the return spring may not act on the first driver so that the spring force of the return spring does not act upon the components of the coupler.

According to a second aspect of the present disclosure, a limb support comprises a spar, a multi-axis coupler supporting the spar, a coupler supported on the spar, and a limb rest supported on the coupler. The multi-axis coupler is releasable to adjust the orientation of the spar relative to a patient support apparatus supporting the limb support. The coupler includes a receiver and a release that is movable relative to the spar. The release is operable to move between a first position wherein the receiver is fixed relative to the spar and a second position wherein the receiver is movable relative to the spar about three-axes. The limb rest is supported on the receiver such that when the release is in the second position, the limb rest is movable relative to the spar to adjust the orientation of a patient's limb relative to the spar and, thereby, a patient support apparatus.

In some embodiments, the limb support further comprises a handle coupled to the release, the handle may be operable to cause the release to move between the first and second.

In some embodiments, the release may be biased to the first position.

In some embodiments, movement of the release from the first position may reduce the frictional force applied to components within the coupler such that the movement of the release continuously reduces the force necessary to move the limb rest relative to the spar.

In some embodiments, the release may include a bias structure that is loaded in the first position to urge components of the coupler together to frictionally lock the coupler with sufficient force to support a patient's limb.

In some embodiments, the bias structure may induce a tension load in tension rod, the tension load acting on components of the coupler to secure the coupler.

In some embodiments, a force applied by the bias structure may be reduced as the release is moved from the first position to the second position thereby reducing frictional force.

In some embodiments, the bias structure may act on a first driver urging the first driver toward a second driver. The bias structure may urge the drivers together with a first spring force in the first position and the release may continuously reduce the spring force to zero as the release is moved from the first position to the second position.

In some embodiments, the drivers may be formed to include inclined surfaces that engage mating surfaces of two wedges. The spring force may push the inclined surface of the first driver against the wedges to urge the wedges apart. The wedges may be constrained by the second driver and a tension rod such that the spring force is transferred through the drivers and wedges to develop tension in the tension rod.

In some embodiments, the release further comprises a cam shaft. The cam shaft may be coupled to the handle such that movement of the handle rotates the cam shaft about a longitudinal axis of the cam shaft to move a cam of the cam shaft from the first position to the second position such that the cam overcomes the spring force of the bias structure in the second position.

In some embodiments, the cam may reduce the spring force of the bias structure as the cam moves from the first to the second position reducing the spring force sufficiently to allow a user to adjust the position of the limb rest relative to the coupler.

In some embodiments, the release may include a floating spacer that is engaged by the cam shaft, the floating spacer moving relative to the drivers. As the cam moves from the first position to the second position, the floating spacer may engage the bias structure to compress the bias structure and may engage the second driver to move the second driver away from the first driver to effect the release of the coupler by releasing the tension in the tension rod.

In some embodiments, the cam shaft may engage a return spring, the return spring biasing the cam shaft to urge the cam shaft toward the first position, the force of the return spring not acting on the first driver so that the spring force of the return spring does not act upon the components of the coupler.

According to a third aspect of the present disclosure, a limb support comprises a spar, a coupler supported on the spar, a limb support supported on the coupler and a handle. The coupler has a release that is selectively actuable to permit movement of the coupler relative to the spar. The handle is coupled to the release of the coupler and positioned such that a user may simultaneously grip the handle and the limb rest. The handle is movable relative to the limb rest so that the user squeezes the handle and the limb rest to move the handle relative to the limb rest. Squeezing of the handle causes the handle to move between a first position wherein the release precludes movement of the coupler and the limb rest and a second position activating the release to permit the coupler to be moved relative to the spar to adjust the position of the limb rest relative to the spar.

In some embodiments, the release may be operable to move between a first position wherein the limb rest is fixed relative to the spar and a third position between the first and second positions wherein the limb rest is movable relative to the spar about three-axes, but the coupler is not movable relative to the spar.

In some embodiments, movement of the release from the first position may reduce the frictional force between the coupler and the spar such that movement of the release continuously reduces the force necessary to move the coupler relative to the spar.

In some embodiments, the release may include a first spar engaging portion and a second spar engaging portion which cooperate to grip the spar. The release may also include a bias member acting between the first spar engaging portion and the second spar engaging portion. The bias member may urge the first spar engaging portion and the second spar engaging portion apart. The bias structure of the release may be operable to overcome the bias member when the release is in the first position.

In some embodiments, the bias structure may induce a tension load in a tension rod, the tension load acting on components of the coupler to secure the coupler.

In some embodiments, the force applied by the bias structure may be reduced as the release is moved from the first position to the third position thereby reducing the tension load in the tension rod.

In some embodiments, the bias structure may act on a first driver urging the first driver toward a second driver. The bias structure may also urge the drivers together with a first spring force in the first position and the release continuously reducing the spring force to zero as the release is moved from the first position to the second position.

In some embodiments, the drivers may be formed to include inclined surfaces that engage mating surfaces of two wedges. The spring force may push the inclined surface of the first driver against the wedges to urge the wedges apart. The wedges may be constrained by a second driver and the tension rod such that the spring force is transferred through the drivers and wedges to develop tension in a tension rod. The tension of the tension rod may secure the components of the coupler against movement.

In some embodiments, the release may further comprise a cam shaft, the cam shaft coupled to the handle such that movement of the handle rotates the cam shaft about a longitudinal axis of the cam shaft to move a cam of the cam shaft from the first position to the third position such that the cam overcomes the spring force of the bias structure in the third position.

In some embodiments, the cam reduces the spring force of the bias structure as the cam moves from the first to the third position. A second position, intermediate the first and third positions, may reduce the spring force sufficiently to allow a user to adjust the position of the limb rest relative to the coupler while maintaining the coupler in a secured position relative to the spar.

In some embodiments, the release may include a floating spacer that is engaged by the cam shaft. The floating spacer may move relative to the drivers. As the cam moves from the first position to the second position, the floating spacer may engage the bias structure to compress the bias structure and engage the second driver to move the second driver away from the first driver to effect the release of the coupler by releasing the tension in the tension rod.

In some embodiments, the cam shaft may engage a return spring, the return spring biasing the cam shaft to urge the cam shaft toward the first position. The force of the return spring may not act on the first driver so that the spring force of the return spring does not act upon the components of the coupler.

According to a fourth aspect, the present invention provides a limb support according to claim <NUM>.

The second end of the restraining device is secured to the limb rest by a bulbous protuberance formed in the restraining device. The bulbous protuberance engage a slot in a wall of the limb rest.

In some embodiments, the restraint may be formed to include a plurality of spaced apart bulbous protuberances to allow for adjustment of the effective length of the restraint.

In some embodiments, the restraint may be resiliently elastic such that the restraint provides flexible engagement with the limb of the patient.

In some embodiments, the pad may be secured to the limb rest by a snap-fit.

In some embodiments, the pad may be secured to the limb rest by at least one pocket that slides over a portion of the limb rest.

In some embodiments, the pad may be secured to the limb rest by two pockets, each pocket sliding over a different portion of the limb rest.

In some embodiments, the pad may be secured to the limb rest by removable rivets.

In some embodiments, the limb rest may be formed to include guide structures for positioning a restraint on the limb rest.

In some embodiments, the mounting structure of the limb rest that engages the coupler may be arranged so that the longitudinal axis of the limb rest is positioned at an angle relative to the coupler.

A limb support configured as a leg support <NUM> mountable to a patient support apparatus (not shown) and for positioning the leg of a patient in a number of different positions is shown in <FIG>. The leg support <NUM> includes a mount <NUM> for mounting the leg support <NUM> to a patient support apparatus as is known in the art. The mount <NUM> supports a lockable multi-axis coupler <NUM> that supports a spar <NUM> illustratively embodied as a rod and permits movement of the spar <NUM> relative to the mount <NUM> in a plurality of directions. An illustrative coupler suitable for use as coupler <NUM> is disclosed in <CIT>, titled "LEG HOLDER SYSTEM FOR SIMULTANEOUS POSITIONING IN THE ABDUCTION AND LITHOTOMY DIMENSIONS".

The spar <NUM> is supported relative to the mount <NUM> by a counterbalancing gas spring <NUM> which assists in supporting the weight of a patient's leg when the leg support <NUM> is in use or the position is being adjusted. A release handle <NUM> positioned on a distal end of the spar <NUM> relative to the mount <NUM> is configured to be used by a user to position the spar <NUM> and includes a release trigger <NUM> that, when gripped by a user, causes the a lockable multi-axis coupler <NUM> to be released to allow the spar <NUM> to move relative to the mount <NUM>. Movement of the spar <NUM> relative to the mount <NUM> is facilitated in the pitch axis <NUM>, roll axis <NUM>, and yaw axis <NUM> as suggested in <FIG>. In the illustrative embodiment, this permits abduction, adduction, and lithotomy adjustments of the patient's leg. In should be understood that the movement could be equally applicable to a patient's arm.

The illustrative leg support <NUM> is configured to support a patient's left leg. In many cases, a second leg support that is a mirror duplicate of the leg support <NUM> will be used to support the right leg of a patient. The present disclosure includes an adjustable coupler <NUM> that permits adjustment of the relative position and orientation of a limb rest <NUM> relative to the spar <NUM>. As will be explained in further detail below, the adjustable coupler <NUM> permits discrete adjustment of the position of the limb rest <NUM> about the spar <NUM> that provides additional roll axis adjustment of the limb rest <NUM>. Still further, the limb rest <NUM> may be rotated about an axis <NUM> shown in <FIG> to change the orientation of the limb rest <NUM> relative to the spar <NUM>.

Referring to <FIG>, the adjustable coupler <NUM> includes a release <NUM> that includes a handle <NUM> that may be pulled in the direction of arrow <NUM> to move the release <NUM> in the direction of arrow <NUM> shown in <FIG>. The operation of the release <NUM> will be discussed in further detail below. As the handle <NUM> is moved in the direction of arrow <NUM>, the handle <NUM> moves to a position adjacent a surface <NUM> of the limb rest <NUM> as shown in <FIG>. A user may apply pressure to a flange <NUM> of the limb rest <NUM> with their thumb while inserting their fingers into a recess <NUM> formed on the handle <NUM>. This allows the user to actuate the handle <NUM> while using a resistive force of their thumb against the flange <NUM> to brace against the resistance of the handle <NUM> and cause the release <NUM> to move to an unlocked position that allows adjustment of the limb rest <NUM> relative to the coupler <NUM>, while simultaneously allowing the coupler <NUM>, and, thereby, the limb rest <NUM> to be moved along the spar <NUM> between two stops <NUM> and <NUM> positioned on the spar <NUM>. Activation of the release <NUM> allows the movement of the limb rest <NUM> about the axis <NUM> as described above, as well as some level of movement about a pitch axis <NUM> and a roll axis <NUM>, while simultaneously allowing movement of the coupler <NUM> along the spar <NUM>. Thus the limb rest <NUM> is adjustable with four degrees of freedom, relative to the spar <NUM>. As will be discussed in further detail below, movement of the handle <NUM> releases the release <NUM> in two stages; the first stage releases the movement about the axes <NUM>, <NUM>, and <NUM> without releasing movement along the spar <NUM>; and the second stage releases all four degrees of freedom.

As discussed above, additional adjustment of the leg support <NUM> includes adjustment of the spar <NUM> relative to the mount <NUM> through the activation of the release trigger <NUM> of the handle <NUM>. Referring to <FIG>, the release trigger <NUM> is movable relative to a grip <NUM> to a position where the release trigger <NUM> is positioned within a space formed in the grip <NUM> so that a user may use the grip <NUM> as a fixed component for leverage to activate the release trigger <NUM> into the position shown in <FIG>. Thus, the release trigger <NUM> is movable between the locked position shown in <FIG> and the release position shown in <FIG>. When released, the spar <NUM> is movable about the axes <NUM>, <NUM>, <NUM>, as described above and as disclosed in the <CIT>, titled "LEG HOLDER SYSTEM FOR SIMULTANEOUS POSITIONING IN THE ABDUCTION AND LITHOTOMY DIMENSIONS". The grip <NUM> is disclosed to include a number of finger channels <NUM> which permit a user to rest their fingers to better grasp the grip <NUM>. Similarly, the release trigger <NUM> also includes finger channels <NUM>.

Referring now to <FIG>, another embodiment of handle <NUM>' includes a grip <NUM>' and a release trigger <NUM>'. However, in the embodiment of <FIG>, the grip <NUM>' and release trigger <NUM>' are formed to include smooth surfaces <NUM> and <NUM>, respectively. The surfaces <NUM> and <NUM> are generally smooth and permit a user's hand to move over the surfaces <NUM> and <NUM> as the spar <NUM> is moved about the axis <NUM>. As shown in <FIG>, the release trigger <NUM>' is received into a space formed in the grip <NUM>' when the release trigger <NUM>' is moved in the direction of the arrow <NUM>, shown in <FIG>, to release the multi-axis coupler <NUM>. This is similar to the way in which release trigger <NUM> is received in grip <NUM> in <FIG>. In both embodiments <NUM> and <NUM>', activation of the respective release triggers <NUM> and <NUM>' causes the multi-axis coupler <NUM> to be released by movement of the release triggers <NUM>, <NUM>' into the respective grips <NUM>, <NUM>'. As will be described in other embodiments below, the movement of the release triggers <NUM>, <NUM>' rotates a rod <NUM> positioned inside of the spar <NUM>, the rod acting on the multi-axis coupler <NUM> to cause it to release, as described in <CIT>.

The coupler <NUM> functions similarly to a coupler <NUM> shown in <FIG> in <CIT> titled "BOOT CARRIAGE FOR REPOSITIONING A SURGICAL BOOT ALONG A SUPPORT ROD". However, the coupler <NUM> of the present disclosure is arranged differently as shown in <FIG> and <FIG>. The coupler <NUM> includes a carriage <NUM> which is supported on the spar <NUM>. The carriage <NUM> includes two arms <NUM>, <NUM> which are separated but drawn together to clamp against the spar <NUM> when the coupler <NUM> is in a locked configuration. The lower portion of the carriage <NUM> is a base <NUM> from which the arms <NUM>, <NUM> extend upwardly in <FIG>. There is a gap <NUM> between the arms <NUM>, <NUM> that provides clearance between the arms <NUM>, <NUM> and the spar <NUM> when the coupler <NUM> is in a released state. Under normal conditions, the coupler <NUM> is biased to draw the arms <NUM>, <NUM> together to grip the spar <NUM> to secure the carriage <NUM> relative to the spar <NUM>.

To bias the arms <NUM>, <NUM> together, a tension rod <NUM> is placed in tension to pull arm <NUM> toward arm <NUM>. The tension <NUM> in tension rod <NUM> overcomes the spring force of a spring <NUM> that is positioned between the arms <NUM>, <NUM> and acts to urge the arms <NUM>, <NUM> apart. The tension rod <NUM> is secured to the arm <NUM> by a bolt <NUM> that is positioned through a hole <NUM> formed in the tension rod <NUM>. The bolt <NUM> is threaded into the arm <NUM> to secure the tension rod <NUM> thereto. The spring <NUM> acts on the tension rod <NUM> and on a face <NUM> of a shaft <NUM> that engages the arm <NUM>. When the tension rod <NUM> is loaded, as will be described in further detail below, the tension <NUM> pivots the arm <NUM> about a pivot <NUM> and urges the arm <NUM> against the spring <NUM>, overcomes the force of the spring <NUM>, and further urges the arm <NUM> against the shaft <NUM>, which is effectively fixed relative to the arm <NUM> so that the load of the tension rod <NUM> causes the arms <NUM> and <NUM> to clamp onto the spar <NUM>.

Referring now to <FIG>, an exploded assembly view of the portion of the coupler <NUM> that provides the portion of the release <NUM> that permits movement of the limb rest <NUM> about the axes <NUM>, <NUM>, and <NUM> is provided. A top housing <NUM> is secured to a driver <NUM> by four screws <NUM>. A floating spacer <NUM> is positioned through the housing <NUM> and the driver <NUM>. The floating spacer <NUM> engages a bias structure <NUM> that includes a number of Belleville washers <NUM> that are stacked together. A driver <NUM> engages with the driver <NUM> to move relative to the driver <NUM> as will be described in further detail below. The tension rod <NUM> passes through the driver <NUM> and is supported relative to the driver <NUM> by spherical bearing <NUM> that is secured to the driver <NUM> by a snap ring <NUM>. The spherical bearing <NUM> facilitates the movement of the driver <NUM>, and thereby, the remainder of the spring-loaded wedge assembly <NUM> relative to the tension rod <NUM> in about the axes <NUM> and <NUM>, when the release <NUM> is in a released state.

A pair of wedges <NUM>, <NUM> are positioned adjacent the driver <NUM> and <NUM> and engaged by the drivers <NUM> and <NUM> as discussed below. The wedges <NUM>, <NUM> are secured together by a pair of springs <NUM>, <NUM> which are each trapped between the driver <NUM> by a pair of plates <NUM>, <NUM> that are secured to the driver <NUM> by three screws <NUM>. The tension rod <NUM> passes through openings in the wedges <NUM>, <NUM>.

A pair of retainers <NUM>, <NUM> are positioned adjacent the respective wedges <NUM>, <NUM> and are engaged with the tension rod <NUM> by a pair of thrust washers <NUM>, <NUM> (see <FIG>). A cover <NUM> overlies the retainer <NUM> and provides a dust cover for portions of the coupler <NUM>. The release is enclosed by two housing members <NUM>, <NUM>.

The coupler <NUM> also includes a cam shaft <NUM> positioned in the top housing <NUM>. The cam shaft <NUM> engages a needle bearing <NUM> which is covered by a crowned band <NUM> that acts on the floating spacer <NUM>. It should be understood that the needle bearing <NUM> and crowned band <NUM> cooperate to reduce the friction required for the cam shaft <NUM> to engage with the floating spacer <NUM>, thereby reducing an activation force for releasing the coupler <NUM> as described below. The needle bearing <NUM> and crowned band <NUM> are secured to the cam shaft <NUM> by snap-rings <NUM> and <NUM>.

The cam shaft <NUM> is positioned in a bearing <NUM> that engages the top housing <NUM> to provide a bearing surface for rotation of the cam shaft <NUM>. The cam shaft <NUM> is retained at the bearing <NUM> by a snap-ring <NUM>. At the opposite end of the cam shaft <NUM>, a return spring <NUM> engages the cam shaft <NUM> to provide a return force for returning the cam shaft <NUM> to a released position as shown in <FIG>. The spring <NUM> engages the cam shaft <NUM> and the top housing <NUM> and is retained in place by a snap-ring <NUM>. The cam shaft <NUM> is also supported by a bearing <NUM> that is secured to the housing <NUM> by a snap-ring <NUM>. A stop <NUM> is positioned through the housing <NUM> to be engaged by a portion of the cam shaft <NUM> to provide a hard stop that limits the rotation of the cam shaft <NUM>.

Referring again to <FIG>, tension <NUM> is developed in the tension rod <NUM> by the interaction of several components of the spring-loaded wedge assembly <NUM> which includes the pair of drivers <NUM>, <NUM> which are urged apart by a bias structure <NUM> such that they act on the of wedges <NUM>, <NUM> to urge the wedges <NUM>. <NUM> apart. The wedges <NUM>, <NUM> then act on the retainers <NUM>, <NUM>, urging the retainers <NUM>, <NUM> apart until they are constrained by the fixed length of the tension rod <NUM> which thereby secures the retainers <NUM>, <NUM> to the wedges <NUM>, <NUM> through the force transferred therethrough.

In use, the bias structure <NUM> urges the driver <NUM> away from the top plate <NUM> such that the inclined surface <NUM> acts on surfaces <NUM>, <NUM> of the wedges <NUM>, <NUM>. As the drivers <NUM> is urged away from the top plate <NUM>, the diameter of the inclined surface <NUM> acting on the wedges <NUM>, <NUM> is forced into the wedges <NUM>, <NUM> so that the wedges <NUM>, <NUM> are urged apart. The second driver <NUM> constrains the wedges <NUM>, <NUM> so that the wedges <NUM>, <NUM> are urged apart. The bias structure <NUM> includes the stack of Belleville washers <NUM> that are constrained by a flange <NUM> of the floating spacer <NUM>. The movement of the floating spacer <NUM> is constrained by the cam shaft <NUM>. The floating spacer further includes a flange <NUM> formed on the end opposite the flange <NUM>, the flange <NUM> engaging the driver <NUM>. The driver <NUM> is engaged by the stack of Belleville washers <NUM> which act on the driver <NUM> to urge the driver <NUM> toward the driver <NUM>, which it telescopically engages so that there may be relative movement between the drivers <NUM> and <NUM>. As the driver <NUM> is driven toward the driver <NUM>, the larger portions of the incline surfaces <NUM> and <NUM> act on the surfaces <NUM> and <NUM> urging the wedges <NUM>, <NUM> apart so that they engage the retainers <NUM>, <NUM> and develop the tension in the tension rod <NUM>.

When the cam shaft <NUM> is rotated about its longitudinal axis <NUM>, the surface of the crowned band <NUM> acts on the flange <NUM> of the floating spacer <NUM> and compresses the stack of Belleville washers <NUM> and effectively pushes the driver <NUM> away from the driver <NUM> to thereby release the pressure developed on the wedges <NUM>, <NUM> As shown in <FIG> where the cam shaft <NUM> is moved to partially compress the bias structure <NUM> so that the drivers <NUM>, <NUM> and wedges <NUM>, <NUM> are in a neutral load. It should be under stood that if the cam shaft <NUM> is rotated further in a first direction, the driver <NUM> will be pushed to disengage the wedges <NUM>, <NUM>. If the cam shaft <NUM> is rotated in a second direction, the floating spacer <NUM> will disengage the driver <NUM> and the full force of the bias structure <NUM> will be transferred through the driver <NUM> to the wedges <NUM>, <NUM> and driver <NUM>.

Movement in the first direction would release the tension in the tension rod <NUM>, allowing the limb rest <NUM> to be adjusted about the axes <NUM>, <NUM>, and <NUM>, as well as allowing the carriage <NUM> to move along the spar <NUM>, thereby providing four degrees of freedom of adjustment of the limb rest <NUM>. The cam shaft <NUM> is connected to and rotated by the handle <NUM> of the release <NUM>, the release <NUM> including the handle <NUM> and the spring-loaded wedge assembly <NUM>, as well as the carriage <NUM>, such that the release <NUM> is operable to release the four degrees of freedom described above. The handle <NUM> is spring loaded and urged to the position of <FIG> by a spring <NUM>, and, effectively, the stack of Belleville washers <NUM>. Movement of the retainers <NUM>, <NUM> relative to the tension rod <NUM> is facilitated by a pair of thrust washers <NUM>, <NUM>, respectively. It should be understood that the rotation of the cam shaft <NUM> may operate to allow movement of the elements of the spring-loaded wedge assembly <NUM> such that the coupler <NUM> can be adjusted relative to the axes <NUM>, <NUM>, <NUM> without releasing the tension in the tension rod <NUM> so that the coupler <NUM> is not free to move relative to the spar <NUM>. Thus, the three degrees of freedom of axes <NUM>, <NUM>, <NUM> may be released without releasing the fourth degree of freedom of movement along the spar <NUM>.

It should be understood that rotation of the carriage <NUM>, and thereby, coupler <NUM> about the spar <NUM> is precluded by the carriage <NUM> being supported on a rail <NUM> that extends between the stops <NUM> and <NUM>. The rail <NUM> is engaged by a bearing <NUM> which is secured to the base <NUM> by a bolt <NUM>.

As shown in <FIG>, another embodiment of limb rest <NUM>' comprises a thermoformed boot/shell <NUM> formed as a single-walled part. The single-walled nature of the part offers the ability to adjust the flexibility of a calf section <NUM> and fin section <NUM> of the shell by adjusting the type and wall thickness of the thermoplastic stock used in the thermoforming process. This flexibility allows for the shell to flex / conform to large calves and lower pressure on the calf. As shown in detail in <FIG>, the edge of the shell <NUM> from a toe <NUM> to the mid-calf region <NUM> includes flanges <NUM> and <NUM>. The flanges <NUM>, <NUM> serve to create a radiused edge to prevent pressure points on the calf of an occupant. The flanges <NUM>, <NUM> also help to secure and guide straps to secure the occupant's limb, as discussed below. Throughout this disclosure, the term strap is used to refer to a restraint of the type that overlies a patient's limb and secures the patient's limb to the limb support structure.

Referring now to <FIG>, a shell mount <NUM> serves as the attachment to a top plate <NUM> of the spring-loaded wedge assembly <NUM>. A recess <NUM> located just forward of the heel <NUM> of the shell <NUM> forms a planar surface to interface with the top plate <NUM>. The recess <NUM> consists of a four-hole bolt pattern timed at an offset angle <NUM>. The offset angle in the illustrative embodiment is a <NUM> degree offset from the longitudinal axis <NUM> of the shell and a central raised protrusion <NUM>. The yaw axis in the spring-loaded wedge assembly <NUM> has a symmetric +/- <NUM> degree rotation with respect to the longitudinal axis of the spar <NUM>. However, the shell <NUM> is required to rotate in yaw parallel to the spar <NUM> to plus <NUM> degrees inwards towards the centerline of the patient support the leg support <NUM> is mounted upon. The timing of the shell mount <NUM> at <NUM> degrees offset from the longitudinal axis of the shell <NUM> allows for a symmetric spring-loaded wedge assembly <NUM> on both the leg support <NUM> and another leg support that is a mirror image/right leg support, while meeting the -<NUM> / +<NUM> degree required yaw rotation.

As shown in <FIG>, in another embodiment of limb rest <NUM>", a shell <NUM>' supports a patient's lower leg and foot may be restrained by a three-strap concept utilizes a first strap <NUM> at the farthest accessible region of the calf, a second strap <NUM> over the ankle and a third strap <NUM> the distal end of the patient's foot. The three-strap design is constraining but secure. Referring now to <FIG>, in yet another embodiment of limb rest <NUM>‴, a two-strap concept utilizes the first strap <NUM> at the farthest accessible point on the calf, and a second strap <NUM> over the mid-foot region of the shell <NUM>. The two-strap design is less constraining and more compliant to foot geometry than the three strap embodiment of <FIG>. The straps <NUM>, <NUM>, <NUM>, and <NUM> are constructed of a cleanable material. In some embodiments the material may include an elastomeric polyurethane rubber or similar elastomeric material or polyester webbing coated with thermoplastic polyurethane (TPU) or polyvinyl chloride (PVC).

<FIG> show various embodiments of strap retention approaches that may be used with either the embodiment of <FIG>, or the embodiment of <FIG>. For example, <FIG> show and embodiment of strap where the strap <NUM> is fed through three slots <NUM>, <NUM>, and <NUM> formed in the wall of the shell on the outboard side of the shell <NUM>. The slot <NUM> is formed in the flange <NUM>. Once fed through the slots <NUM>, <NUM>, and <NUM> a retaining device <NUM> is attached to the strap <NUM>. Once the retaining device <NUM> is attached, the strap <NUM> cannot be pulled back though the slots <NUM>, <NUM>, and <NUM>. The slot <NUM> on the flange <NUM> serves to maintain the position, orientation and visibility of the strap <NUM> when the strap <NUM> is not in use.

<FIG> show alternative embodiments for how the free end of the strap <NUM> may be connected on the inboard sided of the shell <NUM>. For example, <FIG> illustrates that the strap <NUM> has a temporary attachment including a male snap <NUM> attached to the shell <NUM> and multiple female snaps <NUM> spaced equally along the strap <NUM> for incremental adjustment of strap length. To attach the selected female snap <NUM> is pressed onto the male snap <NUM>. In the embodiment of <FIG> a male directional hook <NUM> (hook upwards) is attached to the shell <NUM> and multiple holes <NUM> are punched thru the strap <NUM> and spaced equally along the strap <NUM> for incremental adjustment of strap length. To attach the strap <NUM> to the directional hook <NUM>, the selected hole <NUM> is placed over the hook <NUM> and the strap <NUM> is pulled downwards.

In the embodiment of <FIG>, separate straps <NUM> and <NUM> are secured to the inboard and outboard sides of the shell <NUM> in a manner similar to that used on the outboard side in the embodiment of <FIG>. The outboard strap <NUM> and inboard strap <NUM> are respectively attached to the female <NUM> and male <NUM> sides of a quick release buckle <NUM>. To attach, the female <NUM> and male <NUM> sides of the quick release buckle <NUM> are attached. A portion of the strap <NUM> is pulled to tighten the straps <NUM>, <NUM> as required.

In the embodiment of <FIG>, at the outboard side of the shell <NUM> a strap <NUM> is fed though one slot <NUM> in the wall <NUM> of the shell <NUM> and a retainer <NUM> is added with extra slack provided on the outboard side of the shell <NUM>. On the inboard side of the shell <NUM> the strap <NUM> is looped around and fed through a slot <NUM> which passes radially through a pin <NUM>. The pin <NUM> is located adjacent to the exterior wall <NUM> of the shell and interfaces with two holes which are integral to the shell wall <NUM>. The strap <NUM> is free to be pulled in either direction when the strap <NUM> is orientated as shown in in <FIG>. However, when the strap <NUM> is oriented as shown in in <FIG>, the strap <NUM> will only move freely when pulled in the direction shown by the arrow. When pulled in the opposite direction the pin <NUM> is rotated (clockwise in <FIG>) and pinches the strap <NUM> between the pin <NUM> and the shell <NUM> at the location indicated by a circle <NUM>.

Referring now to <FIG>, another embodiment of a strap for the leg support <NUM> includes a strap <NUM> that is secured to the outboard side of the shell <NUM> through a buckle <NUM>. The strap <NUM> is fed through two slots <NUM>, <NUM> in the buckle <NUM>. The buckle <NUM> includes a friction lock similar to the pin <NUM>. As shown in <FIG>, the strap <NUM> is free to be pulled in either direction when the strap <NUM> is orientated perpendicularly relative to the buckle <NUM>. However, when the strap <NUM> is angled as shown in the alternative, the strap <NUM> will only move freely when pulled in the direction shown by the arrow. The buckle <NUM> has a temporary attachment assembly <NUM> to the inboard side of the shell <NUM>. The temporary attachment assembly <NUM> includes a male directional hook <NUM> (hook down) attached to the shell <NUM>. A single female receptacle <NUM> for the directional snap is present on the buckle <NUM>. To attach, the female receptacle <NUM> is placed over the hook <NUM> and the buckle <NUM> is tilted upwards to secure the buckle to the hook <NUM>. A top loop <NUM> of the strap <NUM> is pulled to tighten the strap <NUM> as required.

Referring to <FIG>, in some embodiments a movable pad <NUM> is positioned on a respective strap, such as strap <NUM>, for example. The strap <NUM> is received through a sleeve <NUM> of the pad <NUM>. The sleeve <NUM> is secured to a pad body <NUM>. The caregiver can position the pad <NUM> between patient leg and strap <NUM>. Referring to <FIG>, in still other embodiments, a strap such as strap <NUM>, for example, may be modified to include a number of foam pads <NUM> along the length of the strap so that the pads <NUM> are positioned between the strap and a patient's leg <NUM>, but are conformable to follow the contour of the patient's leg <NUM>.

In some embodiments, the shell <NUM> may be modified to include a pad positioned between the patient's body and the shell <NUM>. For example, <FIG> disclose a structure which utilizes a flat pattern pad <NUM> that is positionable in the shell <NUM>. Referring to <FIG>, the snaps <NUM>, <NUM> are integrated into the pad <NUM> which is not pictured in <FIG>. Holes <NUM> in the sidewall <NUM> of the shell <NUM> utilize integrated snap features to ensure the heel and foot sections of the pad <NUM> fill in the recessed area <NUM> of the shell <NUM>. As the user presses the pad <NUM> into the shell <NUM>, the snaps <NUM>, <NUM> flex and snap into place. In some embodiments, the snap <NUM> may be omitted and the pad <NUM> may be modified to include a pocket that slides over the toe <NUM> of the shell <NUM> to retain the pad <NUM> on the shell <NUM>. In other embodiments, the pad <NUM> may be modified by sewing the pad <NUM> into a three-dimensional shape to conform the pad to the contour of the shell <NUM>. The modified three-dimensional pad may be retained by a pocket over the toe <NUM>, our may have one or more of the snaps <NUM>, <NUM> integrated into the pad structure to retain the three-dimensional pad to the shell <NUM>. As shown in <FIG>, the pad <NUM> includes relieve notches <NUM>, <NUM> to assist with fitting the pad <NUM> into the shell <NUM>. A flap <NUM> of the pad <NUM> is configured to overlie the fin section <NUM> of the shell <NUM> while the flap <NUM> is configured to overlie the calf section <NUM> of the shell <NUM>.

Referring now to <FIG>, a shell <NUM> is shown. Shell <NUM> is similar to shell <NUM> discussed above, however shell <NUM> includes features formed in the respective flanges <NUM>, <NUM> that are configured to help guide and retain both a pad, similar to pad <NUM>, or to guide straps, similar to strap <NUM>. For example, an aperture <NUM> is formed in a wall <NUM> of shell <NUM> adjacent a notch <NUM> that is formed in the flange <NUM>. A protrusion <NUM> is formed on the inboard side <NUM> of the shell <NUM>. The protrusion <NUM> is T-shaped and configured to receive a free end of the strap similar to that shown in <FIG>. One side of the strap can be fixed at the aperture <NUM> and notch <NUM>, with the free end being draped over a patient's limb positioned in the shell <NUM> and secured at protrusion <NUM>. Similar structures are positioned at the heel region <NUM> and toe region <NUM> as shown in <FIG>.

Referring now to <FIG>, a blank for a pad <NUM> is shown to include a pocket <NUM> position two overlie a calf supporting portion of a shell, such as shell <NUM>. Another pocket <NUM> is positioned to overlie the toe portion of a shell, such as shell <NUM>. In addition to securing the pad <NUM> with the pockets <NUM>, <NUM>, the pad may be further secured in some embodiments by a plurality of removable rivets. The locations <NUM> noted on the pad <NUM> provide potential connecting points for the removable rivets. When the rivets are used, corresponding holes <NUM> are formed in the shell <NUM>. The rivets are then secured through the pad <NUM> and the shell <NUM>. Various embodiments of rivets are shown in the <FIG>. Several embodiments of rivets <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are shown in the <FIG>.

Referring now to <FIG>, another embodiment of a handle <NUM> for releasing the multi-axis coupler <NUM> is shown to include a release trigger <NUM> and a grip <NUM>. <FIG> shows that the release trigger <NUM> engages with a pair of couplers <NUM>, <NUM> which are secured to a rod <NUM>. A bevel gear <NUM> is supported on the rod <NUM> such that rotation of the rod <NUM> as indicated by arrow <NUM> causes the bevel gear <NUM> to rotate. The rod <NUM> has a D-shape which is received in a through hole of the bevel gear <NUM> to transfer rotation from the rod <NUM> to the bevel gear <NUM>. The bevel gear <NUM> acts on a bevel gear <NUM> which is secured to an actuation rod <NUM> so that the rotation of bevel gear three and <NUM> is transferred through bevel gear <NUM> the actuation rod <NUM> to thereby release the multi-axis coupler <NUM>.

In yet another embodiment shown in <FIG>, a handle <NUM> includes a release trigger <NUM> and a grip <NUM>. A shield <NUM> is interposed between the release trigger <NUM> and the grip <NUM>. As shown in <FIG>, the release trigger <NUM> is secured to a couple or <NUM> by a set screw <NUM> so that rotation of the release trigger <NUM> in the direction of arrow <NUM>, the multi-axis coupler <NUM> is released.

<FIG> illustrate various embodiments of release handles that may be used with a release, such as the release <NUM> of the embodiment of <FIG>. <FIG> shows a limb support <NUM> that has a handle <NUM> that connects to both ends of a cam shaft, such as cam shaft <NUM>. <FIG> shows an alternative arrangement of a limb support <NUM> where the coupler <NUM> is reversed and a handle assembly <NUM> includes a grip <NUM> secured to a lever arm <NUM>. The lever arm <NUM> is attached to a cam shaft, such as cam shaft <NUM> and the grip <NUM> is positioned so that a user may place their thumb or palm on the shell of the limb rest <NUM> and their fingers on the grip <NUM> to use the shell as leverage in causing rotation of the cam shaft. <FIG> shows an arrangement of limb support <NUM> similar to the arrangement of <FIG>, however the cam shaft is actuated by a handle <NUM> that is supported on two lever arms <NUM>, <NUM> that each engage the cam shaft.

<FIG> illustrate two embodiments of a non-round cross-section of a spar. The spar <NUM> shown in <FIG> provides for movement of a carriage <NUM>, similar to carriage <NUM> to move, without the support of the lower rail <NUM> of the embodiment of <FIG>. Thus, the spar <NUM> prevents the carriage <NUM> from rotating about the spar <NUM> in the direction of arrow <NUM>. <FIG> also shows a non-round cross-section of a spar <NUM> that would be suitable for use to eliminate the need for the lower rail <NUM>.

Another embodiment of a coupler arrangement for securing the strap <NUM> to a shell <NUM> is shown in <FIG>. The strap <NUM> forms a tension lock <NUM> with a buckle <NUM>, where the buckle <NUM> is inserted into a receiver <NUM> formed in the flange <NUM> on the inboard side of the shell <NUM>. The buckle <NUM> includes resiliently pliable, curved arms <NUM> which are coupled to the frame <NUM> of the buckle <NUM> by a base <NUM> as shown in <FIG>. The free end of each arm <NUM> includes a clasp <NUM>, which engages a catch <NUM> in the receiver <NUM> to secure the buckle in the receiver <NUM>, and a grip <NUM>, which is deformable by a user to deflect the arm <NUM> towards the frame <NUM> of the buckle <NUM> to disengage the clasp <NUM> from the catch <NUM> in order to remove the buckle <NUM> from the receiver <NUM>. The arms <NUM> are biased to urge the clasp <NUM> away from the frame <NUM> in order to engage the catch <NUM> with the receiver <NUM> when the buckle is inserted into the slot <NUM> of the receiver <NUM>. The receiver <NUM> formed in the flange <NUM> on the side of the shell <NUM> as shown in <FIG>.

A cross-section of the upper portion of the buckle <NUM> is shown in <FIG> illustrates the strap <NUM> forming the tension lock <NUM> with the buckle <NUM>. The tension lock <NUM> is formed by three features of the buckle <NUM>: a slot <NUM>, an angled surface <NUM>, and a slot <NUM>. The slot <NUM> is formed by distal sides <NUM> of the frame <NUM> so that the slot <NUM> communicates between a front surface <NUM> of the buckle <NUM> and a back surface <NUM> of the buckle <NUM>. The angled surface <NUM> forms an acute, downward angle with the front surface <NUM> of the buckle. The slot <NUM> is formed by the distal sides <NUM> of a top surface <NUM> of the buckle <NUM> so that the slot <NUM> communicates between the top surface <NUM> of the buckle <NUM> and the slot <NUM>. To form the tension lock <NUM>, the strap <NUM> is inserted into the slot <NUM> from the back surface <NUM> of the buckle <NUM> and routed through to the front surface <NUM> of the buckle <NUM>, as indicated by arrow <NUM>. The strap <NUM> is then routed up and around the angled surface <NUM>, as indicated by arrow <NUM>, and down through the slot <NUM> from the top surface <NUM> of the buckle <NUM> and back into the slot <NUM>, as indicated by arrow <NUM>. The strap <NUM> is further routed out from the back surface <NUM> of the buckle <NUM> through the slot <NUM>, as indicated by arrow <NUM>. Tension on the free end of the strap <NUM>, as indicated by arrow <NUM>, will tighten the strap <NUM>, and the angled surface <NUM> will maintain the tension lock <NUM>.

When the buckle <NUM> is not engaging the receiver <NUM>, the buckle <NUM> is in a free position, as shown in <FIG>. The buckle <NUM> has a bottom width <NUM> that is smaller than a middle width <NUM>. The receiver <NUM> has a width <NUM> that is greater than the bottom width <NUM> of the buckle <NUM>, but smaller than the middle width <NUM> of the buckle <NUM>. When a user applies a downward force, as indicated by arrow <NUM>, on the buckle <NUM>, the buckle <NUM> will remain in a free position in the receiver <NUM>, as a result of the bottom width <NUM> of the buckle <NUM> being smaller than the width <NUM> of the receiver <NUM>, until the arms <NUM> of the buckle <NUM> make contact with the flange <NUM>, as a result of the middle width <NUM> of the buckle <NUM> being larger than the width <NUM> of the receiver <NUM>, causing the arms <NUM> to deform and putting the buckle <NUM> in a deflected position, as shown in <FIG>. As the user continues to apply a downward force, indicated by arrow <NUM>, on the buckle <NUM> into the receiver <NUM>, the deflected arms <NUM> slide past the flange <NUM> and the clasp <NUM> engages with the flange <NUM> to secure the buckle <NUM> in place, resulting in an engaged position as shown in <FIG>. To disengage the clasps <NUM> from the flange <NUM> in order to remove the buckle <NUM> from the receiver <NUM>, the grips <NUM> of the arms <NUM> are squeezed by the user to bring the arms <NUM> closer to the frame <NUM> of the buckle <NUM>. This puts the buckle <NUM> in a deflected position, causing its middle width <NUM> to be smaller than the width of the receiver <NUM>, allowing the buckle <NUM> to be routed up and out of the receiver <NUM>.

Referring now to <FIG>, another embodiment of strap/restraint that includes a main portion <NUM> that engages a slot <NUM> of a shell <NUM>. A locking portion <NUM> includes alternating portions of depressions <NUM> and bulbous protuberances <NUM>. The depressions <NUM> are configured to be received in a slot <NUM> formed in the shell <NUM> and the bulbous protuberances <NUM> engage with the shell <NUM> to secure the restraint when it is engaged with a patient's limb. To release the restraint, a user needs to merely pull the locking portion <NUM> out of engagement with the slot <NUM>.

Referring now to <FIG>, a limb support <NUM> includes a shell <NUM> that has a structure similar to that disclosed in <FIG> to allow a user to utilize the restraint of <FIG>. The limb support <NUM> includes a handle <NUM> that is coupled to the cam shaft <NUM> of the coupler <NUM>. The handle <NUM> is shown in a locked position in <FIG>. To actuate the handle <NUM>, a user positions their thumb or palm on the shell <NUM> and slips their fingers around the handle <NUM>. Squeezing their fingers with their thumb and/or palm braced against the shell <NUM>, the handle <NUM> is moved between a locked position shown in <FIG> and a released position shown in <FIG>. The released position causes the coupler <NUM> to be released to allow the limb rest/shell <NUM> to move relative to the coupler <NUM> and the coupler <NUM> to move relative to the spar <NUM>.

Claim 1:
A limb support (<NUM>) comprising
a spar (<NUM>),
a coupler (<NUM>) supported on the spar (<NUM>), the coupler (<NUM>) having a release (<NUM>) that is selectively actuable to permit movement of the coupler (<NUM>) relative to the spar (<NUM>),
a limb rest (<NUM>) supported on the coupler (<NUM>),
a handle (<NUM>) coupled to the release (<NUM>) of the coupler (<NUM>), the handle (<NUM>) positioned such that a user may simultaneously grip the handle (<NUM>) and the limb rest (<NUM>), the handle (<NUM>) being movable relative to the limb rest (<NUM>), wherein movement of the handle (<NUM>) towards the limb rest (<NUM>) activates the release (<NUM>) to allow the limb rest position and orientation relative to the spar (<NUM>) to be adjusted,
a pad (<NUM>, <NUM>, <NUM>, <NUM>) positioned on the limb rest (<NUM>), the pad (<NUM>, <NUM>, <NUM>, <NUM>) being secured to the limb rest (<NUM>), and
at least one restraint (<NUM>) secured to the limb rest (<NUM>), the limb rest (<NUM>) configured to engage a limb of a patient to secure the pad (<NUM>, <NUM>, <NUM>, <NUM>) to the restraint (<NUM>), wherein the restraint (<NUM>) comprises a first end coupled to the limb rest (<NUM>) by a retaining device (<NUM>) secured to the restraint (<NUM>), the restraint (<NUM>) passing through an opening (<NUM>, <NUM>, <NUM>) in a wall of the limb rest (<NUM>) and the retaining device (<NUM>) being sized to prevent the retaining device (<NUM>) from passing through the opening (<NUM>, <NUM>, <NUM>),
wherein a second end (<NUM>) of the restraint (<NUM>) is secured to the limb rest (<NUM>) by a bulbous protuberance (<NUM>) formed in the restraint (<NUM>), the bulbous protuberance (<NUM>) engaging a slot (<NUM>) in a wall of the limb rest (<NUM>).