Patent Publication Number: US-2023157851-A1

Title: Breathable Residual-Limb Socket System

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/629,822, filed on Jan. 9, 2020, which is a U.S. national phase under § 371 of International Patent Application No. PCT/US18/41519, filed on Jul. 10, 2018, which claims priority to U.S. Provisional Patent Application No. 62/530,762, filed on Jul. 10, 2017. The entirety of each of these applications is hereby incorporated herein by reference. 
    
    
     GOVERNMENT LICENSE RIGHTS 
     This invention was made with government support under Contract No. W81XWH-14-2-0197, awarded by the Department of Defense. The government may have certain rights in the invention. 
    
    
     BACKGROUND 
     Field of the Invention 
     The embodiments described herein are generally directed to a residual limb socket system, and, more particularly, to a breathable residual-limb socket system that admits air and allows sweat to evaporate from the surface of the residual limb. 
     Description of the Related Art 
     Conventional residual-limb socket systems utilize a liner, which is pulled over the residual limb, in conjunction with a socket, which is pulled over the liner. However, these conventional prostheses often use materials that have thermally insulating properties. For example, conventional liners are made of thick rubber, foam, or leather. This creates a microclimate in which heat, trapped inside the socket, can make the residual limb hot, sweaty, and uncomfortable. These hot, moist conditions within the prostheses can exacerbate skin problems on the residual limb, as well as reduce mobility and function of the residual limb. 
     Some liners, such as the Endolite Silcare Breathe™ and Uniprox SoftSkin Air™, have micro-pores to improve breathability. However, as confirmed by testing, even with these micro-pores in the liner, the residual limb is not able to receive the amount of air necessary for evaporative cooling. 
     Thus, what is needed is a breathable residual-limb socket system that is sufficiently air-permeable so as to allow evaporative cooling on the surface of the residual limb. 
     SUMMARY 
     Accordingly, a breathable residual-limb socket system is disclosed. In an embodiment, the system comprises a liner sock to be worn on the residual limb, the liner sock comprising: air-permeable textile forming a substantially cylindrical portion that is closed on a distal end and open on a proximal end and comprising an internal surface and an external surface; and a friction-interface material that covers only a portion of the internal surface of the air-permeable textile, such that, when worn on the residual limb, the friction-interface material contacts a surface of the residual limb, and an uncovered portion of the air-permeable textile which the friction-interface material does not cover allows air to pass between an external environment of the liner sock and the surface of the residual limb. 
     In an embodiment, the air-permeable textile comprises: a first section comprising unidirectional-stretch textile; and at least one second section comprising bidirectional-stretch textile. The first section may be fixed to the at least one second section by at least one seam, and the friction-interface material may cover the seam on the internal surface of the air-permeable textile. The air-permeable textile may comprise two second sections comprising bidirectional-stretch textile. The friction-interface material may cover an entire internal surface of the first section comprising unidirectional-stretch textile, but not cover an entire internal surface of the at least one section comprising bidirectional-stretch textile. 
     In an embodiment, the friction-interface material comprises a plurality of longitudinal strips that extend in a longitudinal direction of the liner sock and that are spaced apart from each adjacent one of the plurality of longitudinal strips, around a circumference of the liner sock, by the uncovered portion of the air-permeable textile. The friction-interface material may comprise a strip that extends around a circumference of the liner sock at a proximal end of the liner sock. The friction-interface material may comprise a plurality of circumferential strips that extend around a circumference of the liner sock and that are spaced apart from each adjacent one of the plurality of circumferential strips, in a longitudinal direction of the liner sock, by the uncovered portion of the air-permeable textile. In an embodiment, the friction-interface material comprises a plurality of dots. The friction-interface material may comprise a distal cup at a distal end of the liner sock. The friction-interface material may comprise silicone gel. 
     In an embodiment, the liner sock further comprises a distal cap on an external surface of the closed distal end of the liner sock. The distal cap may comprise a countersunk threaded hole configured to receive a screw pin. 
     In an embodiment, the system further comprises a socket to be worn, either directly or indirectly, over the liner sock, the socket comprising: a perforated inner layer; and an outer frame comprising one or more fenestrations, through which the perforated inner layer is exposed to an external environment of the socket. The perforated inner layer may comprise a plurality of holes having a diameter of 5 millimeters or less. The outer frame may comprise an anterior fenestration and at least one posterior fenestration. The outer frame may comprise at least two posterior fenestrations. The perforated inner layer may comprise fabric. The outer frame may comprise carbon fiber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The details of the present invention, both as to its structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
         FIGS.  1 A- 1 C  illustrate exterior perspective views of a liner sock, according to an embodiment; 
         FIGS.  2 A- 2 C  illustrate exterior plan views of a liner sock, according to an embodiment; 
         FIGS.  3 A and  3 B  illustrate interior plan views of a liner sock, according to a first embodiment; 
         FIGS.  4 A and  4 B  illustrate interior plan views of a liner sock, according to a second embodiment; 
         FIGS.  5 A and  5 B  illustrate interior plan views of a liner sock, according to a third embodiment; 
         FIGS.  6 A and  6 B  illustrate interior plan views of a liner sock, according to a fourth embodiment; 
         FIGS.  7 A and  7 B  illustrate interior plan views of a liner sock, according to a fifth embodiment; 
         FIG.  8 A  illustrates a layer of a socket, according to an embodiment; 
         FIGS.  8 B- 8 F  illustrate various exterior views of a socket, according to a first embodiment; 
         FIGS.  9 A and  9 B  illustrate exterior views of a socket, according to a second embodiment; and 
         FIGS.  10 A- 10 C  illustrate usage of a liner sock and socket, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In an embodiment, a breathable residual-limb socket system is disclosed. After reading this description, it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications. However, although various embodiments of the present invention will be described herein, it is understood that these embodiments are presented by way of example and illustration only, and not limitation. As such, this detailed description of various embodiments should not be construed to limit the scope or breadth of the present invention as set forth in the appended claims. 
     1. System 
     In an embodiment, the breathable residual-limb socket system comprises one or both of a liner sock and a socket. 
     1.1. Liner Sock 
       FIG.  1 A  illustrates a perspective view, from a distal end to a proximal end, of the front of the exterior of a liner sock  100 , while  FIG.  1 B  illustrates a side of the exterior of liner sock  100  (e.g., the liner sock  100  in  FIG.  1 A , rotated 90° to the left), according to an embodiment. Liner sock  100  may be formed from at least one section  110  of unidirectional-stretch textile and at least one section  120  of bidirectional-stretch textile. The unidirectional-stretch textile of section(s)  110  is manufactured to have elasticity primarily in a single direction (e.g., in the longitudinal direction of liner sock  100 ), whereas the bidirectional-stretch textile of section(s)  120  is manufactured to have elasticity primarily in two directions (e.g., in the longitudinal and lateral directions of liner sock  100 ). The unidirectional-stretch textile and/or the bidirectional-stretch textile should be air-permeable and/or breathable, so as to allow evaporative cooling through the textile. 
     In the illustrated embodiment, liner sock  100  comprises a single section  110  of unidirectional-stretch textile and two sections  120 A and  120 B of bidirectional-stretch textile. As shown sections  120 A and  120 B of bidirectional-stretch textile are each generally rectangular with a curved distal end. Each section  120 A and  120 B of bidirectional-stretch textile is joined to section  110  of unidirectional-stretch textile by a U-shaped seam  130 A and  130 B, respectively. In addition, opposing edges of section  110  of unidirectional-stretch textile may be joined to each other by seam  130 C, to form a substantially cylindrical or partially cylindrical liner sock  100 . Bidirectional-stretch sections  120 A and  120 B may be on opposite sides of the substantially cylindrical portion of liner sock  100 , such that, around a circumference of liner sock  100 , bidirectional-stretch sections  120 A and  120 B are spaced apart from each other on both sides by interposed portions of unidirectional-stretch section  110 . 
     In an embodiment, the distal end of liner sock  100  comprises a distal cap  140  and a threaded countersunk hole  142  for receiving a screw pin  146 . Distal cap  140  is affixed to the distal end of unidirectional-stretch section  100  and/or an internal distal cup (e.g., distal cup  144 , illustrated in other figures), with a distal portion of unidirectional-stretch section  110  sandwiched between distal cap  140  and the distal cup, to thereby close the distal end of liner sock  100 . Distal cap may comprise or consist of polyurethane rubber or a similar material, and may be affixed to liner sock  100  and/or the distal cup within liner sock  100  via stitching, adhesives, and/or the like. Countersunk hole  142  is configured to receive a standard, threaded screw pin  146 , which is commonly used for the suspension of prosthetic limbs. Of course, the proximal end of liner sock  100  remains open or openable to receive the residual limb of the user. 
       FIG.  1 C  illustrates the front of liner sock  100 , with the proximal end of liner sock  100  partially rolled down to show an interior portion of liner sock  100 , according to an embodiment. As shown, the internal surface of liner sock  100  may comprise strips  150 ,  152 , and/or  154 . Each strip  150 ,  152 , and/or  154  may comprise or consist of silicone gel or a similar friction-interface material. 
     In an embodiment, a plurality of spaced longitudinal strips  150  extend longitudinally (i.e., vertically when liner sock is upright) down the internal surface of liner sock  100 . A circumferential strip  152  may also be provided around the entire circumference of liner sock  100  at or near the proximal end of liner sock  100 . In addition, a plurality of seam strips  154  may cover the internal surface of seams  130 , to prevent liner sock  100  from slipping, as well as to prevent seams  130  from irritating the skin of the residual limb. It should be understood that the internal surfaces of seams  130 A,  130 B, and  130 C may each be covered by a seam strip  154 , and that the respective seam strip  154  may follow the curvature of seams  130 A and  130 B. 
     Strips  150 ,  152 , and/or  154  may be sized and spaced to provide a comfortable friction fit, while allowing a significant portion of the internal surface of liner sock  100  (e.g., 50% or more of the internal surface) to remain uncovered. In addition, strips  150 ,  152 , and/or  154  may be positioned over targeted anatomical regions to provide cushioning to sensitive anatomical regions (e.g., the distal tibia, tibial tubercle, tibial crest, tibial condyles, fibular head, etc.) and/or suspension loading to tolerant anatomical regions (e.g., patellar tendon, medial tibial flare, fibular shaft, popliteal fossa, gastrocnemius, etc.). The friction fit, provided by strips  150 ,  152 , and/or  154 , prevents liner sock  100  from slipping off of the residual limb during use of a suspended prosthesis, while the uncovered portions of the internal surface of liner sock  100  (i.e., in conjunction with the uncovered external surface of liner sock  100 ) allow air to permeate the textile of liner sock  100 . This air-permeability of liner sock  100  enables evaporative cooling on the skin of the residual limb within liner sock  100 . 
       FIG.  2 A- 2 C  illustrate plan views of liner sock  100 , according to an embodiment. Specifically,  FIG.  2 A  illustrates a front view of liner sock  100 ,  FIG.  2 B  illustrates a back view of liner sock  100 , and  FIG.  2 C  illustrates a side view of liner sock  100 . It should be understood that, with respect to liner sock  100 , the terms “front,” “side,” and back” are simply used for the convenience of relating the illustrations to each other, and that liner sock  100  does not need to be oriented on the residual limb in any particular fashion (e.g., the front of liner sock  100  may be aligned to the posterior of the residual limb, etc.). However, to obtain the benefit of sections  120 A and  120 B of bidirectional-stretch textile, one of these sections  120 A and  120 B should be oriented on the anterior of the residual limb (e.g., such that it passes over the front of the knee), while the other one of these sections should be oriented on the posterior of the residual limb (e.g., such that it passes over the back of the knee). 
       FIGS.  3 A and  3 B  illustrate front and side views of an internal surface of liner sock  100 , according to a first embodiment. In other words, these views illustrate liner sock  100  when flipped inside-out. As shown, the internal surface of liner sock  100  comprises strips  150 ,  152 , and  154 , which may comprise or consist of silicone gel or a similar friction-interface material, as is commonly used for cushioning residual-limb liners and is well known in the art. Longitudinal strips  150  comprise N strips extending longitudinally across a portion or an entirety of the longitudinal length of the inner surface of liner sock  100 . N may be any number greater than or equal to one and preferably greater than one. However, as discussed elsewhere herein, longitudinal strips  150  should be numbered and spaced so as to leave uncovered textile between adjacent pairs of longitudinal strips  150 . For example, each longitudinal strip  150  may be approximately half-an-inch in width and be spaced from each adjacent longitudinal strip  150 , along the circumference of liner sock  100 , by approximately half-an-inch or more. 
     While longitudinal strips  150  are shown as stopping at seams  130 A and  130 B and not extending across sections  120 A and  120 B of bidirectional-stretch textile, in alternative embodiments, strips  150  may extend longitudinally across sections  120 A and  120 B (e.g., as demonstrated in  FIG.  1 C ). Circumferential strip  152  is a continuous strip along the entire circumference of a proximal end of the internal surface of liner sock  100 . Strips  154  cover and follow the inner surfaces of seams  130 , to prevent or reduce contact between seams  130  and the skin of the user&#39;s residual limb, thereby preventing or reducing skin irritation. 
     In an embodiment, the internal surface of liner sock  100  comprises a distal cup  144 . Distal cup  144  may comprise silicone gel or a similar friction-interface material, and may comprise the same material or a different material than strips  150 ,  152 , and/or  154 . In an embodiment, distal cup  144  comprises the same material as strips  150 ,  152 , and/or  154 , but has greater thickness. Distal cup  144  is configured to comfortably receive the distal end of the user&#39;s residual limb. Preferably, distal cup  144  should have a low durometric measure to aid in comfort at the distal end of the residual limb. 
       FIGS.  4 A and  4 B  illustrate front and side views of an internal surface of liner sock  100 , according to an alternative, second embodiment. In this second embodiment, longitudinal strips  150  and seams strips  154  may be the same as described above. However, in this second embodiment the internal surface of liner sock  100  comprises a plurality of circumferential strips  152 , with each circumferential strip  152  extending along the entire circumference of liner sock  100 . The number of circumferential strips  152  may comprise any number greater than one. However, as discussed elsewhere herein, circumferential strips  152  should be numbered and spaced so as to leave uncovered textile between adjacent pairs of circumferential strips  152 . For example, each circumferential strip  152  may be approximately half-an-inch in width and be spaced from each adjacent circumferential strip  152 , along the longitudinal axis of liner sock  100 , by approximately half-an-inch or more. 
     Circumferential strips  152  may be spaced substantially equidistantly along the longitudinal axis of liner sock  100 . As shown, circumferential strips  152  extend across sections  120 A and  120 B of bidirectional-stretch textile. However, in alternative embodiments, at least some of circumferential strips  152  may extend circumferentially across section  110  of unidirectional-stretch textile, but stop at seams  130 A and  130 B so as not to extend circumferentially across sections  120 A and  120 B of bidirectional-stretch textile. 
       FIGS.  5 A and  5 B  illustrate front and side views of an internal surface of liner sock  100 , according to an alternative, third embodiment. In this third embodiment, seam strips  154  may be the same as described above, and the internal surface of liner sock  100  may comprise the same plurality of circumferential strips  152  described in the second embodiment illustrated in  FIGS.  4 A and  4 B . However, in the third embodiment, the internal surface of liner sock  100  does not comprise any longitudinal strips  150 . 
     Advantageously, in embodiments which utilize a plurality of spaced circumferential strips  152  (e.g., the second embodiment illustrated in  FIGS.  4 A and  4 B , and the third embodiment illustrated in  FIGS.  5 A and  5 B ), liner sock  100  can be cut to size and still have a proximal circumferential strip  152 . Specifically, to shorten liner sock  100  to more appropriately match the length of the residual limb, a user can cut liner sock  100  laterally. For example, if the user cuts liner sock  100  laterally between circumferential strips  152 C and  152 D, circumferential strips  152 A,  152 B, and  152 C will be discarded with the separated portion of liner sock  100 , and circumferential strip  152 D will act as the new proximal circumferential strip to comfortably friction-fit the proximal edge of liner sock  100  to the residual limb. 
       FIGS.  6 A and  6 B  illustrate front and side views of an internal surface of liner sock  100 , according to an alternative, fourth embodiment. In this fourth embodiment, the internal surface of liner sock  100  comprises dots  156 . Like strips  150 ,  152 , and/or  154 , dots  156  may comprise or consist of silicone gel or a similar friction-interface material, and provide the same comfort, friction fit as strips  150 ,  152 , and/or  154 . The internal surface of liner sock  100  may still comprise circumferential strip  152  along the proximal, internal circumference of liner sock  100 , and/or may still comprise seam strips  154  following the internal surfaces of seams  130 . Alternatively, the internal surface of liner sock  100  may comprise only dots  156 , i.e., without any of strips  150 ,  152 , and  154 . 
       FIGS.  7 A and  7 B  illustrate front and side views of an internal surface of liner sock  100 , according to an alternative, fifth embodiment. In this fifth embodiment, the internal surface of section  110  of unidirectional-stretch textile of liner sock  100  is entirely covered by material  158 , whereas the internal surfaces of sections  120 A and  120 B of bidirectional-stretch textile are not covered by any material (or only partially covered by material  158  within a vicinity of seams  130 ). Notably, the internal surfaces of seams  130  may be covered by material  158 . Like strips  150 ,  152 , and/or  154 , and/or dots  156 , material  158  may comprise or consist of silicone gel or a similar friction-interface material, and provide the same comfort, friction fit as strips  150 ,  152 , and/or  154 , and/or dots  156 . 
     1.2. Socket 
       FIGS.  8 A- 8 F  illustrates a socket  200 , according to a first embodiment. In the illustrated embodiment, socket  200  comprises a perforated inner layer  210  and an outer frame  220 . Socket  200  may be worn over a stump sock  300 , which is worn over liner sock  100 . Stump sock  300  can be used to provide volume management. Specifically, the volume of the residual limb may change throughout the course of a day. Thus, stump socks  300  of differing thicknesses (i.e., different ply) may be used, throughout the day, to fill the varying amounts of space between liner sock  100  and socket  200 , caused by the changes in limb volume. Stump sock  300  and socket  200  both comprise holes at their distal ends to allow the passage of a pin screw (e.g., pin screw  146  in  FIGS.  10 A- 10 C ), when the pin screw is threaded into countersunk hole  142  of liner sock  100 . 
     As illustrated in  FIG.  8 A , perforated inner layer  210  is an air-permeable layer that comprises a plurality of perforations or holes  212 , through which air may pass. In an embodiment, each hole may be small (e.g., 5 millimeters or less in diameter) to avoid excessive tissue strain or other skin problems on the residual limb. Perforated inner layer  210  may be made from polypropylene, polyethylene, nylon, or other thermo-formable plastic, or a copolymer of such plastics. 
     As illustrated in  FIG.  8 B , outer frame  220  is attached over perforated inner layer  210 . Outer frame  220  comprises one or more fenestrations or windows, which expose one or more portions of perforated inner layer  210  to the external environment. In the first embodiment, illustrated in  FIGS.  8 A- 8 F , outer frame  220  comprises three such fenestrations. Outer frame  220  may comprise or consist of carbon fiber for lightweight durability. 
     In an embodiment, socket  200  is custom made for the residual limb of its user. For example, perforated plastic may be drape-molded over a positive model of the user&#39;s residual limb or three-dimensionally printed, and covered in perforated, air-permeable fabric to create perforated inner layer  210 . A carbon fiber outer frame  220  may then be molded over the custom-molded perforated inner layer  210 , and the outer frame  220  may be affixed to the perforated inner layer  210  by standard means, such as stitching, adhesive, and/or the like. The perforations and fenestrations may be strategically positioned to provide breathability to the areas of the user&#39;s residual limb which heat up the most during the use of a prosthesis. 
       FIGS.  8 C and  8 D  illustrate the front of socket  200  in plan view and perspective view, respectively. As illustrated, outer frame  220  comprises an anterior, symmetrical fenestration on the front of socket  200 . This anterior fenestration enables air from the external environment to pass through perforated inner layer  210 , via holes  212 , to the internal environment of socket  200 , and/or enables air from the internal environment of socket  200  to pass through perforated inner layer  210 , via holes  212 , to the external environment. The front of socket  200 , illustrated in  FIGS.  8 C and  8 D , corresponds to the anterior of the residual limb, and therefore, the anterior fenestration provides breathability, primarily, to the anterior of the user&#39;s residual limb. 
       FIGS.  8 E and  8 F  illustrate the back of socket  200  in plan view and perspective view, respectively. As illustrated, in the first embodiment, outer frame  200  comprises two, separate posterior fenestrations on the back of socket  200 . Each posterior fenestration is offset from the center and separated from the other posterior fenestration by a strip of outer frame  220 . Each posterior fenestration enables air from the external environment to pass through perforated inner layer  210 , via holes  212 , to the internal environment of socket  200 , and/or enables air from the internal environment of socket  200  to pass through perforated inner layer  210 , via holes  212 , to the external environment. The back of socket  200  corresponds to the posterior of the residual limb, and therefore, the left-posterior fenestration provides breathability, primarily, to the left-posterior of the user&#39;s residual limb, while the right-posterior fenestration provides breathability, primarily, to the right-posterior of the user&#39;s residual limb. Advantageously, the posterior fenestrations allow air to reach the posterior of the user&#39;s residual limb, which is typically the area that heats up the most during use of prostheses. 
       FIGS.  9 A and  9 B  illustrate socket  200  in side and back plan views, respectively, according to a second embodiment. Unlike the first embodiment, the second embodiment only has a single posterior fenestration, which may be similar or identical to the anterior fenestration illustrated in  FIGS.  8 C and  8 D . The second embodiment of socket  200  may have an anterior fenestration that is similar or identical to the anterior fenestration of the first embodiment of socket  200 , illustrated in  FIGS.  8 C and  8 D . 
     2. Usage of System 
       FIGS.  10 A- 10 C  illustrate how liner sock  100  and socket  200  may be used, according to an embodiment. As illustrated in  FIG.  10 A , liner sock  100  may be pulled over the residual limb. This may be performed by turning liner sock  100  inside-out (e.g., as illustrated in  FIG.  1 C ), placing the distal end of the user&#39;s residual limb into distal cup  144 , and then rolling liner sock  100  up onto the user&#39;s residual limb. It should be understood that liner sock  100  may be manufactured in a variety of sizes to fit a wide range of residual limbs. A pin screw  146  may be screwed into countersunk hole  142  on liner sock  100 , either before or after stump sock  300  and/or socket  200  have been placed over liner sock  100 . 
     As illustrated in  FIG.  10 B , stump sock  300  is pulled over liner sock  100 . As described elsewhere herein, stump sock  300  provides volume management and may be replaced with a stump sock  300  of different ply, as needed over time, due to changes in the volume of the user&#39;s residual limb. In some cases, stump sock  300  may not be necessary, and may be omitted, in which case socket  200  may be placed directly over liner sock  100 . 
     As illustrated in  FIG.  10 C , socket  200  is pulled over liner sock  100  and/or stump sock  300 . Socket  200  may be held to liner sock  100  and the residual limb using a pin-suspension technique or other lanyard-style system on the sides or end of liner sock  100  (e.g., the system manufactured by Coyote Design™ of Boise, Id.). In any case, a prosthesis (e.g., a prosthetic leg and foot) may be affixed to pin screw  146 , with socket  200  providing suspension of the prosthesis from the residual limb. Any commercial pin-locking system may be used to affix the prosthesis to pin screw  146 . While embodiments are illustrated herein as using pin suspension, it should be understood that these embodiments may be adapted to use other common suspension means, such as sleeve, suction, and/or elevated vacuum suspension. 
     Advantageously, as discussed above, liner sock  100  utilizes air-permeable textile(s), with internal strips  150 ,  152 , and/or  153 , or dots  156  of silicone gel or similar friction-interface material, to provide a comfort, friction fit. Because the outer surface of the air-permeable textile is uncovered and a significant amount of the inner surface of the air-permeable textile is uncovered, the textile of liner sock  100  admits air into the inner environment of liner sock  100  and allows sweat to evaporate from the surface of the user&#39;s residual limb. In other words, liner sock  100  improves breathability in the internal environment of liner sock  100 . 
     Furthermore, as discussed above, socket  200  utilizes one or more fenestrations that expose a perforated inner layer  210  to the external environment. This allows air to pass between the internal and external environments of socket  200 , via holes  212  in perforated inner layer  210 . Therefore, socket  200  improves the breathability in the internal environment of socket  200 . 
     Thus, the disclosed liner sock  100  and the disclosed socket  200 , both individually and in combination, improve ventilation and breathability to the user&#39;s residual limb and provide an “air-conditioned” effect. It should be understood that, in the event that a stump sock  300  is used between liner sock  100  and socket  200 , a stump sock  300  with breathable characteristics should be utilized, so as to not inhibit the improved breathability characteristics of the liner sock  100  and/or socket  200 . 
     The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly not limited.