Patent Publication Number: US-2022211962-A1

Title: Nasal mask and securement system

Description:
BACKGROUND 
     Field 
     The present disclosure generally relates to components for medical systems for conveying gases to and/or from a patient. In one particular aspect, the disclosure relates to patient interfaces that form a part of a breathing system. 
     Description of the Related Art 
     In assisted breathing, respiratory gases are supplied to a patient through a patient interface via flexible breathing tube. The patient interface can be a nasal cannula, nasal mask, full face, oral mask or oro-nasal mask, endotracheal tube, or other known types of interfaces. The gases expired by the patient may be channeled through a similar breathing tube to other equipment (valves, ventilators, pressure devices, or the like) or expelled to the patient&#39;s surroundings. 
     In medical applications, such as assisted breathing, the gases inhaled by a patient are preferably delivered close to body temperature (usually between 33° C. and 37° C.) and with a high relative humidity (commonly near saturation). In other medical applications, such as continuous positive airway pressure (CPAP) systems or positive pressure ventilations systems that provide patient&#39;s suffering obstructive sleep apnea (OSA) with positive pressure breathing gases, the breathing gases may be heated and/or humidified to varying levels to improve user comfort or supplied without heating or humidification. 
     In the specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the disclosure. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. 
     SUMMARY 
     It would be advantageous to provide a system for an alternative or improved interface location or operational positioning of the interface, such as a nasal cannula, nasal mask, or oro-nasal mask. Such an alternative or improved system may further assist with improved compliance of gas delivery treatment. 
     An aspect of the disclosure involves a patient interface comprising a mask seal body defining a breathing chamber and having a user-contacting surface configured to contact a face of the user and surround at least the nares of the user. The interface also comprises a pair of facial pads, each of the facial pads configured to engage the face of a user on opposing sides of the mask seal body. The interface further comprises a pair of bridging portions, each of the bridging portions connecting the mask seal body and a respective one of the facial pads. Each of the bridging portions has a curved shape configured in use to urge the mask seal body toward the user&#39;s face to create or maintain sealing engagement between the user-contacting surface and the user&#39;s face. 
     In some configurations, the bridging portion comprises one or more cutouts. 
     In some configurations, a mechanical fastener component is positioned within the cutout(s). 
     In some configurations, the mechanical fastener component is a hook or loop material. 
     In some configurations, the bridging portion comprises one or more locating features. 
     In some configurations, as the one or more locating features are grooves. 
     In some configurations, a mechanical fastening material, such as a hook or loop material is positioned within the locating feature(s) such as groove(s). 
     In some configurations, a mechanical fastener component is positioned within the groove(s). 
     In some configurations, the bridging portion comprises a portion having a mechanical fastener component. 
     In some configurations, the mechanical fastener component is a hook or loop material. 
     In some configurations, the bridging portion comprises a clip configured to retain a respiratory tube. 
     In some configurations, each of the bridging portions is split into an upper section and a lower section that are separate from one another. 
     In some configurations, the bridging portions are constructed integrally with the mask seal body. 
     In some configurations, the bridging portions are constructed separately from the mask seal body and connected thereto. 
     In some configurations, the bridging portion comprises an S-shape, a U-shape or a C-shape as viewed from above. 
     In some configurations, the patient interface further comprises a reinforcing element configured to support the structure of the mask seal body. 
     In some configurations, the reinforcing element is an elongated strip overmoulded on or within the mask seal body. 
     In some configurations, the reinforcing element is a clip positioned at a front surface of the mask seal body. 
     In some configurations, the bridging portion is integrally constructed with the clip. 
     In some configurations, the reinforcing element is a hardened interface tube connection attached to the mask seal body. 
     In some configurations, the reinforcing element is a thickened portion of the mask seal body. 
     In some configurations, the reinforcing element is at least one of (i) an elongated strip overmoulded on or within the mask seal body; (ii) a clip positioned at a front surface of the mask seal body; (iii) a hardened interface tube connection attached to the mask seal body; and (iv) a thickened portion of the mask seal body. 
     In some configurations, the bridging portion is integrally constructed with the clip. 
     In some configurations, the mask seal body comprises an upper region, wherein at least part of the upper region is configured to roll when the mask seal body is positioned on a user&#39;s face. 
     In some configurations, the upper region comprises a portion with a thinner wall located between portions having thicker walls. 
     In some configurations, the mask seal body is configured to be placed around an alar region of a user. 
     In some configurations, the mask seal body includes an under-nose support configured to be placed under a nose of a user when the interface is worn by the user. 
     In some configurations, the interface includes one or more respiratory tubes configured to deliver gas. 
     In some configurations, the respiratory tubes comprise an inspiratory tube configured to deliver gas to a user. 
     In some configurations, the respiratory tubes comprise an expiratory tube configured to deliver gas from a user. 
     In some configurations, the mask seal body includes a tube receiving portion configured to receive the one or more respiratory tubes. 
     In some configurations, the tube receiving portion comprises elongate tube extensions extending from the mask seal body. 
     In some configurations, the elongate tube extensions vary in cross-sectional size or shape along a length of the elongate tube extensions. 
     In some configurations, the elongate tube extensions further comprise regions with a first part of a releasable connector for connection with a second part of a releasable connector on the respective bridging portion. 
     In some configurations, the bridging portion is configured to receive the respiratory tube. 
     In some configurations, the tube receiving portion comprises one or more swivel connectors. 
     In some configurations, the mask is overmolded to the respiratory tubes. 
     In some configurations, the one or more swivel connectors comprise elbows having an angle of less than 90 degrees, preferably about 45 degrees. 
     In some configurations, the one or more respiratory tubes connect to the mask seal body at an angle of between 0-90 degrees, preferably about 45 degrees. 
     In some configurations, at least one of the bridging portions defines an internal flow path. 
     In some configurations, the patient interface further comprises a patch assembly coupled to each of the facial pads for securing the facial pads to the user. 
     In some configurations, the patch assembly comprises a first portion coupled to the facial pad and a second portion configured to be coupled to the user, wherein the patch assembly is configured for releasable connection between the first portion and the second portion. 
     In some configurations, the patient interface further comprises a third facial pad configured to engage the forehead of the user above the mask seal body and a third bridging portion connecting the mask seal body and the third facial pad. 
     In some configurations, the mask seal body comprises a reduced stiffness region. 
     In some configurations, the reduced stiffness region is located in an upper portion of the mask seal body. 
     In some configurations, the reduced stiffness region comprises a reduced thickness relative to portions of the mask seal body above and/or below the reduced stiffness region. 
     In some configurations, the reduced stiffness region has a triangular or substantially triangular profile. 
     In some configurations, the triangular or substantially triangular profile has a rounded apex. 
     In some configurations, an upper edge of the reduced stiffness region defines a dip. 
     In some configurations, the reduced stiffness region is a rolling region configured to roll onto another portion of the mask seal body. 
     An aspect of the present disclosure involves a patient interface comprising a mask seal body defining a breathing chamber and having a user-contacting surface configured to contact a face of the user and surround at least the nares of the user. The patient interface also comprises a pair of facial pads, each of the facial pads configured to engage the face of a user on opposing sides of the mask seal body. The facial pads are coupled to the mask seal body. 
     In some configurations, a sealing mechanism is configured to urge the mask seal body toward the user&#39;s face to create or maintain sealing engagement between the user-contacting surface and the user&#39;s face. 
     In some configurations, the sealing mechanism is integral with the mask seal body. 
     In some configurations, the sealing mechanism is formed separately from the mask seal body. 
     In some configurations, the sealing mechanism comprises a strap. 
     In some configurations, the sealing mechanism comprises a bridging portion that extends between the mask seal body and each of the facial pads. 
     In some configurations, the bridging portion defines a curved shaped configured to roll in response to movement between the facial pad and the mask seal body. 
     In some configurations, the bridging portion comprises one or more hinges. 
     In some configurations, the bridging portion comprises one or more cutouts. 
     In some configurations, a hook or loop material is positioned within the cutout(s). 
     In some configurations, a mechanical fastener component is positioned within the cutout(s). 
     In some configurations, the bridging portion comprises one or more locating features, such as grooves. 
     In some configurations, a hook or loop material is positioned within the locating feature(s) such as groove(s). 
     In some configurations, a mechanical fastener component is positioned within the groove(s). 
     In some configurations, the bridging portion comprises a portion having a mechanical fastener component. 
     In some configurations, the mechanical fastener component is a hook or loop material. 
     In some configurations, the bridging portion comprises a clip configured to retain a respiratory tube. 
     In some configurations, each of the bridging portions is split into an upper section and a lower section that are separate from one another. 
     In some configurations, wherein the patient interface further comprises a reinforcing element configured to support the structure of the mask seal body. 
     In some configurations, the reinforcing element is an elongated strip overmoulded on or within the mask seal body. 
     In some configurations, the reinforcing element is a clip positioned at a front surface of the mask seal body. 
     In some configurations, the bridging portion is integrally constructed with the clip. 
     In some configurations, the reinforcing element is a hardened interface tube connection attached to the mask seal body. 
     In some configurations, the reinforcing element is a thickened portion of the mask seal body. 
     In some configurations, the mask seal body comprises an upper region, wherein at least part of the upper region is configured to roll when the mask seal body is positioned on a user&#39;s face. 
     In some configurations, the upper region comprises a portion with a thinner wall located between portions having thicker walls. 
     In some configurations, the mask seal body is configured to be placed around an alar region of a user. 
     In some configurations, the mask seal body includes an under-nose support configured to be placed under a nose of a user when the interface is worn by the user. 
     In some configurations, the patient interface further comprises one or more respiratory tubes configured to deliver gas. 
     In some configurations, the respiratory tubes comprise an inspiratory tube configured to deliver gas to a user. 
     In some configurations, the respiratory tubes comprise an expiratory tube configured to deliver gas from a user. 
     In some configurations, the mask seal body includes a tube receiving portion configured to receive the one or more respiratory tubes. 
     In some configurations, the tube receiving portion comprises elongate tube extensions extending from the mask seal body. 
     In some configurations, the elongate tube extensions vary in cross-sectional size or shape along a length of the elongate tube extensions. 
     In some configurations, the tube receiving portion comprises one or more swivel connectors. 
     In some configurations, the one or more swivel connectors comprise elbows having an angle of less than 90 degrees, preferably about 45 degrees. 
     In some configurations, the one or more respiratory tubes connect to the mask seal body at an angle of between 0-90 degrees, preferably about 45 degrees. 
     In some configurations, at least one of the bridging portions defines an internal flow path. 
     In some configurations, the patient interface further comprises a patch coupled to each of the facial pads for securing the facial pads to the user. 
     In some configurations, the patch comprises a first portion coupled to the facial pad and a second portion configured to be coupled to the user, wherein the patch assembly is configured for releasable connection between the first portion and the second portion. 
     In some configurations, a third facial pad configured to engage the forehead of the user above the mask seal body and a third bridging portion connecting the mask seal body and the third facial pad. 
     In some configurations, the mask seal body comprises a reduced stiffness region. 
     In some configurations, the reduced stiffness region is located in an upper portion of the mask seal body. 
     In some configurations, the reduced stiffness region comprises a reduced thickness relative to portions of the mask seal body above and/or below the reduced stiffness region. 
     In some configurations, the reduced stiffness region has a triangular or substantially triangular profile. 
     In some configurations, the triangular or substantially triangular profile has a rounded apex. 
     In some configurations, an upper edge of the reduced stiffness region defines a dip. 
     In some configurations, the reduced stiffness region is a rolling region configured to roll onto another portion of the mask seal body. 
     Further aspects and advantages of the present disclosure will become apparent from the ensuing description which is given by way of example only. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Throughout the drawings, reference numbers can be reused to indicate general correspondence between reference elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the disclosure. 
         FIG. 1  shows an example of a system in which embodiments of the patient interface can be used. 
         FIG. 2A  is a front, top and side perspective view of a mask seal. 
         FIG. 2B  is a top view of the mask seal of  FIG. 2A . 
         FIG. 2C  is a front view of the mask seal of  FIG. 2A . 
         FIG. 2D  is a rear view of the mask seal of  FIG. 2A . 
         FIG. 3  is a schematic drawing of a rear view of a mask seal. 
         FIG. 4  is a schematic drawing showing a region of the face of a user where a mask seal is applied. 
         FIG. 5  is a rear, top and side perspective view of a mask seal. 
         FIG. 6A  is a front, top and side perspective transparent view of a mask seal revealing the internal structure of the mask seal. 
         FIG. 6B  is a top projected view of the mask seal of  FIG. 6A . 
         FIG. 6C  is a front projected view of the mask seal of  FIG. 6A . 
         FIG. 6D  is a rear projected view of the mask seal of  FIG. 6A . 
         FIG. 7A  is a front, top and side perspective view of a reinforcing structure for a mask seal. 
         FIG. 7B  is a top view of the reinforcing structure of  FIG. 7A . 
         FIG. 7C  is a front view of the reinforcing structure of  FIG. 7A . 
         FIG. 8A  is a front, top and side perspective view of a mask seal. 
         FIG. 8B  is a side view of the mask seal of  FIG. 8A . 
         FIG. 8C  is a front view of the mask seal of  FIG. 8A . 
         FIG. 9A  is a front, top, and side perspective view of a patient interface. 
         FIG. 9B  is a top view of the patient interface of  FIG. 9A . 
         FIG. 9C  is a front view of the patient interface of  FIG. 9A . 
         FIG. 9D  is a rear view of the patient interface of  FIG. 9A . 
         FIG. 10A  is a front, top and side perspective view of a mask seal. 
         FIG. 10B  is a top view of the mask seal of  FIG. 10A . 
         FIG. 11  is a top view of a mask seal positioned on a user&#39;s face. 
         FIG. 12A  is front, top and side perspective view of a mask seal. 
         FIG. 12B  is a front, top and side perspective projected view of the mask seal of  FIG. 12A . 
         FIG. 12C  is a top projected view of the mask seal of  FIG. 12A . 
         FIG. 12D  is a front projected view of the mask seal of  FIG. 12A . 
         FIG. 12E  is a rear projected view of the mask seal of  FIG. 12A . 
         FIG. 13  is a front, top and side perspective view of a mask seal. 
         FIG. 14  is a front, top and side perspective view of a mask seal. 
         FIGS. 15A-B  are front, top and side perspective views of a patient interface. 
         FIG. 16A  is a front, top and side perspective view of a mask seal. 
         FIG. 16B  is a top view of the mask seal of  FIG. 17A  with an interface tube. 
         FIG. 17A  is a perspective view of a connector for a patient interface. 
         FIG. 17B  is another perspective view of the connector of  FIG. 18A . 
         FIG. 18A  is a front, top and side perspective view of a mask seal. 
         FIG. 18B  is a top view of the mask seal of  FIG. 18A . 
         FIG. 18C  is a front view of the mask seal of  FIG. 18A . 
         FIG. 18D  is a rear view of the mask seal of  FIG. 18A . 
         FIG. 19  is a front, top and side perspective view of a mask seal. 
         FIG. 20  is a front, top and side perspective view of a mask seal. 
         FIG. 21A  is a front, top and perspective view of a mask seal. 
         FIG. 21B  is a front view of the mask seal of  FIG. 21A . 
         FIG. 21C  is a rear view of the mask seal of  FIG. 21A   
         FIG. 21D  is a side view of the mask seal of  FIG. 21A . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of systems, components and methods of assembly and manufacture will now be described with reference to the accompanying figures, wherein like numerals refer to like or similar elements throughout. Although several embodiments, examples and illustrations are disclosed below, it will be understood by those of ordinary skill in the art that the inventions described herein extends beyond the specifically disclosed embodiments, examples and illustrations, and can include other uses of the inventions and obvious modifications and equivalents thereof. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner simply because it is being used in conjunction with a detailed description of certain specific embodiments of the inventions. In addition, embodiments of the inventions can comprise several novel features and no single feature is solely responsible for its desirable attributes or is essential to practicing the inventions herein described. 
     Certain terminology may be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “above” and “below” refer to directions in the drawings to which reference is made or directions relative to an orientation of the device as used with the user in an upright position. Terms such as “front,” “back,” “left,” “right,” “rear,” and “side” describe the orientation and/or location of portions of the components or elements within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the components or elements under discussion or relative to an orientation of the device as used with the user in an upright position. 
     Respiratory System 
       FIG. 1  shows an example respiratory system  1  in which embodiments of the patient interface  100  can be used. In the illustrated arrangement, the patient interface  100  receives an inspiratory flow of gases via an inspiratory conduit  201   a , and a flow of the expiratory gases is directed from the interface  100  via an expiratory conduit  201   b  to a resistance device, which in the illustrated arrangement is a bubbler device  70 . An optional humidifier system  30  is provided to humidify the inspiratory flow of gases. The humidifier system  30  typically includes a chamber sitting atop a heater base, the chamber of which is fed with a source of gases flow from, for example, a hospital or other supply source  3000 . The humidified inspiratory flow of gases is delivered to the airway of the patient by inspiratory conduit  201   a  and the patient interface  100 . Excess and expired gases are evacuated from the patient interface  100  by the expiratory conduit  201   b . The resistance device  70  provides resistance to the expiratory flow of the gases exiting the system  1  to the atmosphere to provide a desirable peak end expiratory pressure (PEEP). One of skill in the art will understand that such a system may include additional and/or replacement components as are known in the art. In some embodiments, the patient interface  100  is a mask. For example, the patient interface  100  may be a nasal mask, an oro-nasal mask, an oral mask or a full-face mask. In some embodiments, the resistance device and/or the humidifier may be integrated into the supply source  3000 . Although a water-based resistance device is shown in  FIG. 1 , it should be appreciated by one of skill that the resistance device may be any other mechanical or electrical resistance device as is known in the art. 
     Patient Interface 
       FIGS. 2A-D  illustrates a mask  200  which may comprise or be included in a patient interface, such as the patient interface  100 . In some embodiments, the mask  200  includes a seal body  210  which may be applied on the face of a patient. In the illustrated arrangement, the seal body  210  is a nasal seal applied over a nose of a patient, forming a seal on or about the nose surrounding the nares of the patient. In some embodiments, the seal body  210  could cover both a nose and a mouth of the patient. The illustrated mask  200  includes one or more feet, cheek supports or facial pads  250  for the securement or supporting of the mask  200  relative to the user, and one or more side arms or bridging portions  230  each extending from the seal body  210  and connecting the facial pad  250  with the seal body  210 . 
     In the illustrated arrangement, each of the facial pads  250  includes a base or connecting portion  235  that is coupled directly to the respective bridging portion  230 . In some configurations, the base or connecting portion  235  is configured to provide support to a face-contacting portion of the facial pad  250 . For example, the base or connecting portion  235  can assist in maintaining a shape (e.g., a curved shape) of the face-contacting portion of the facial pad  250 . In the illustrated arrangement, the base or connecting portion  235  is generally triangular in shape as viewed from above (see, e.g.,  FIG. 2B ) and includes a long strut portion and a short strut portion that cooperate to define an opening that passes through the base or connecting portion  235  in a vertical direction (relative to the orientation in the figures or as worn with the user in an upright position). It should be appreciated by one of skill in the art that such an opening may reduce cost (for example, by reducing material) and impart flexibility on the connection between the bridging portion and the facial pad  250 . However, such an opening may be optional as it may add complexity in manufacturing the interface. Therefore, the base or connecting portion  235  may be solid. Alternatively, rather than having a long and short strut portions, the opening may define any suitable shape. 
     In some embodiments, the seal body  210  is permanently or semi-permanently connected with the bridging portions  230 . In some embodiments, the seal body  210  and the bridging portions  230  are integrally formed in a single, unitary piece. In some embodiments, the seal body  210 , the bridging portions  230 , and the facial pads  250  may be integrally formed in a single, unitary piece. For example, the seal body  210 , the bridging portions  230  and the facial pads  250  may be molded as a single piece from a single material, or co-molded as a single piece from different materials. In some embodiments, the seal body  210  and the bridging portions  230  are removably or releasably coupled such that the seal body  210  may be removed for cleaning or replacement if required. Additionally, the ease of manufacturing may be improved if the seal body  210  and the bridging portions  230  are individually formed and subsequently assembled or coupled. 
     As shown in  FIGS. 2A-B , in some embodiments, the seal body  210  includes a tube receiving portion  214  in the form of a tube coupling or manifold for connecting a breathing chamber or mask cavity  260  of the seal body  210  with one or more interface tubes (not shown). In some embodiments, the tube receiving portion  214  may be connected to an inspiratory tube and an expiratory tube. In some embodiments the inspiratory tube and expiratory tube may be coaxial. In some embodiments, the tube receiving portion  214  may be connected directly or indirectly with conduits similar to, for example, the inspiratory conduit  201   a  and/or the expiratory conduit  201   b  described in relation to  FIG. 1 . In some embodiments, as illustrated in  FIGS. 2A-B , the tube receiving portion  214  may include openings  216 ,  218  which can receive the interface tubes and allow gas flow from and to the patient via the mask cavity  260  of the seal body  210 . In some embodiments, the patient ends of interface tubes may be overmoulded together or connected to a single piece. In this embodiment, the tube receiving portion  214  may have a single opening to receive the single piece. In some embodiments, a tube receiving portion with a single opening may connect to receive a tube in which the inspiratory and expiratory tube are coaxial. In some embodiments, the seal body  210  includes the tube receiving portion  214  at the anterior side of the seal body  210 , or a non-patient facing side of the seal body  210 . As illustrated in  FIGS. 2A-D , the tube receiving portion  214  is shaped to receive the interface tubes at an angle of approximately 45° relative to the width (side-to-side) direction of the seal body  210 . In some embodiments, the tube receiving portions  214  is shaped to receive the interface tubes in a perpendicular direction to the width of the seal body  210 , or in a parallel direction to the width of the seal body  210 . 
     The seal body  210  comprises a cushion portion  215  that defines a face-contacting surface  220  having an inner peripheral edge  222  that defines a nose-receiving opening into the mask cavity  260  for receiving the user&#39;s nose in use. In some embodiments, the tube receiving portion  214  may be located generally opposite the face-contacting surface  220 . In use, the patient interface  100  is secured against the user&#39;s face such that the contacting surface  220  of the seal body  210  envelops or circumscribes a portion of the user&#39;s nose defining the nares and sealingly engages about the user&#39;s nose such as against the cheek surfaces and/or lateral side surfaces of the user&#39;s nose, the upper lip region below the user&#39;s nose, and across the nasal bridge region or nasal tip region of the user&#39;s nose. The seal body  210  may be substantially hollow and generally shaped to provide or define the seal cavity  260  for receiving the flow of gases from the tube receiving portion  214 . The seal cavity  260  may be fluidically connected with the openings  216  and  218 , such that gas from and to the patient flows through the cavity  260 . 
     The seal body  210  may include an upper portion  212  at the top of the seal body  210 . The upper portion  212  may be configured to extend over a nasal bridge and/or nasal tip and/or ala of the user. In some embodiments, the upper portion  212  may be designed to roll over onto an outer surface the seal body  210 . In some embodiments, the upper portion  212  may roll onto another portion of the seal body  210 . To assist with the rolling of the upper portion  212 , the upper portion  212  may have a varying thickness or a varying stiffness. In some embodiments, to induce the upper portion  212  to roll, a reduced stiffness region  211  can be incorporated. The reduced stiffness region  211  can reduce or eliminate the likelihood of the seal body  210  buckling or adversely deforming in a region other than the desired region for rolling. In some embodiments, other means for providing the reduced stiffness region  211  also can be used to induce rolling of the upper portion  212 . For example, the material of the upper portion  212  can be configured to have a reduced stiffness through material selection or material properties. In addition, a composite of materials can be used to provide a region of reduced stiffness or rigidity. Moreover, a combination of any suitable techniques can be used. 
     When the upper portion  212  comprises the reduced stiffness region  211 , the upper portion  212  of the seal body  210  may tend to balloon outward under internal pressures, such as those encountered during positive pressure therapy regimens, which ballooning is believed to be caused by the reduced stiffness region  211  that defines a large area of silicone or flexible materials without significant structure. With reference to  FIGS. 6A-B , to reduce the prevalence of ballooning in the upper portion  212  and/or to provide enhanced structure in the upper portion  212 , a support structure, such as a band  224 , can be positioned along at least a portion of the upper portion  212 . For example, the band  224  can be formed at least in part by a region of significantly increased thickness relative to the reduced stiffness region  211 , where the region is formed of the same material forming the seal body  210 . In other arrangements, the band  224  can be or include a component formed of a material that has increased stiffness relative to the silicone or other material(s) forming the seal body  210 . 
     In some embodiments, the band  224  can be a separately formed component that is at least partially encased by the material of the seal body  210 . For example, the band  224  can be a preformed plastic component and the seal body  210  can be overmoulded onto or around the band  224 . In some configurations, the band  224  can be defined by a portion of the upper portion  212  that has enhanced stiffness relative to surrounding regions. For example, but without limitation, the band  224  can be defined by one or both of a portion of increased thickness, a portion of differing materials or material properties that result in increased stiffness or the like. The band  224  may extend along at least a portion of the upper portion  212  of the seal body  210 . 
     In some embodiments, the face-contacting surface  220  may be shaped such that the face-contacting surface  220  substantially corresponds to or can accommodate the contour of the face of the user and form a fluid-tight seal or a substantially fluid-tight seal during normal use. For example, as illustrated in  FIG. 2B , in a top view, the left and right sides of the seal body  210  protrude into the patient&#39;s alar region, as opposed to the middle portion, which curves away from the face to accommodate the nose. Moreover, in the illustrated arrangement, the top surface of the seal body  210  (which contacts the nose) dips further away than the lower surface of the seal body  210  (which contacts the upper lip). This allows the seal body  210  to be positioned lower down on the nose of the user in comparison to designs having a flatter face-contacting surface. Advantageously, such an arrangement causes or allows the seal body  210  to be positioned away from the eyes and on a region of the nose made up of cartilage and fat, which is less likely to be susceptible to skin irritation than regions with bone and less fat. 
       FIG. 3  illustrates a schematic view of the seal body  210  from the face-contacting side or posterior side of the seal body  210 . In some embodiments, as shown by a striped region in  FIG. 3 , a region  213  of the upper portion  212  (“rolling region”) may be designed to roll as described herein. The rolling region  213  can be formed by and/or be coextensive with a reduced stiffness region (such as the reduced stiffness region  211  of  FIGS. 2A-2D or 6A-6D ). In some embodiments, the wall thickness of the seal body  210  may be substantially constant through the rolling region  213 , while relatively thicker along the bottom and front portions of the mask, thereby providing support for the structure of the seal body  210 . The rolling region  213  may thus comprise a thin walled portion positioned between a pair of comparatively thicker walled portions. The rolling region  213  can be positioned on or adjacent the upper portion  212  of the seal body  210  to permit at least part of the upper portion  212  to deform downwardly relative to a lower portion of the seal body  210 . The rolling region  213  may extend laterally across the seal body  210 . However, other arrangements to induce or facilitate rolling in the rolling region  213  can also be used. Examples of mask seals comprising rolling portions are disclosed in WO2014/062070, the entirety of which is incorporated by reference herein. 
     As shown in  FIG. 3 , the rolling region may have a triangular or substantially triangular profile, with an apex  280 . The apex  280  can be defined as a tip, a top and an angular summit of the seal body  210 , in which apex  280  is positioned in proximity to the nasal bridge of the user when in use. The apex  280  may have an angle  282  selected to be large enough to provide a relatively flat profile, such that the apex  280  of the seal body  210  does not interfere with eyes of the user. In other arrangements, the apex may be very slight and/or rounded, rather than triangular. In some embodiments, there may be no central or single apex, and instead, a central portion of an upper edge of the seal may dip down, such as in the seal body  810  of  FIGS. 8A-C . Such designs may advantageously avoid sealing across the sensitive bridge of the nose, as discussed above. 
     In some embodiments, the bridging portions  230  may be connected to the seal body  210  at a region other than the rolling region  213  of the upper portion  212  of the seal body  210 , such that the movement of the bridging portions  230  do not interfere with the rolling of the rolling region  213 . For example, the bridging portions  230  may be connected to a side portion, a bottom portion, or a front portion of the seal body  210 . 
     In some embodiments, the inner peripheral edge  222  of the seal body  210  is shaped and/or sized such that the face-contacting surface  220  does not touch the alar region of the nose of the user. As a result, as shown in  FIG. 4 , a mask seal region  223 , which is an area defined by a location of the inner peripheral edge  222  on the face of the user, extends above the upper lip at its lower end, below the bridge of the nose (i.e. near the supratip of the nose) at its upper end, and away from the alae  224  of the nose on its side. In some embodiments, the seal body  210  may be sized and/or shaped to have different mask seal regions. For example, the seal body  210  may be an oro-nasal mask, and the mask seal region may extend around a user&#39;s nose and mouth. In some embodiments, the seal body  210  may include sealing pillows and/or nasal prongs to facilitate sealing with nares of the user. In some embodiments, the seal body  210  may be sized and/or shaped to seal in the alar region of the patient. 
     In some embodiments, the seal body  210  may include an under-nose support, which can contact or engage under the user&#39;s nose to generate an opposing downward force that at least partially counteracts, resists or otherwise mitigates the resultant force generated by the patient interface and exhalation force to thereby stabilize the nasal mask in place over the user&#39;s nose during use and/or inhibit or prevent its tendency to slide or otherwise move up the user&#39;s face from its initially secured position prior to gas delivery being initiated. An under-nose support may also help to resist rocking of the mask against the patient&#39;s face, in particular, vertical or chin to forehead rocking. 
       FIG. 5  illustrates a seal body  510  having an under-nose support  520 . The seal body  510  is similar to the seal body  210  described in relation to  FIGS. 1-4 , and the seal body  510  may include all or some features of the seal body  210 , and in some embodiments, the mask  200  may include the seal body  510  instead of the seal body  210 . For example, the bridging portion  230  may be connected to the seal body  510 . The under-nose support  520  of the nasal mask assembly can be sized, positioned and/or otherwise configured to contact at least a portion of an under-nose surface of the user&#39;s nose. The under-nose support  520  may extend within the mask cavity  560  that receives the user&#39;s nose in use and has a contact surface that is configured to contact at least a portion of the under-nose surface of the user&#39;s nose but without obstructing or completely obstructing the user&#39;s nostrils. Depending on the size of the user&#39;s nose, the under-nose support may contact a portion or portions of the under-nose surface without any obstruction of the user&#39;s nostrils or only partially obstructs one or both nostrils. The under-nose support  520  may include one or more extension or connection portions that extend from within the mask cavity  560  and connect to an edge of a contacting surface of the seal body  510  in an upper lip region of the seal body  510 . The under-nose support  520  may vary in thickness across its length from a thinner end at or toward the end connecting to the face contacting portion of the seal body  510 , to a thicker region at or near the opposing end. Various embodiments of the nasal mask interface and nasal seals of the interface with the under-nose support is further described in International Publication No. WO 2017/216708, published on Dec. 21, 2017, the entirety of which is incorporated by reference herein. 
     Reinforcing Element 
     In some embodiments, a seal body of a mask, such as the seal body  210  or the seal body  510 , may include a reinforcing element, which can provide additional support to the structure of the seal body and thus the nasal mask. The reinforcing element may reduce movement of the mask or seal body caused by the exertion of external force, thereby facilitating the maintenance of a suitable seal with the face of the user. For example, the reinforcing element may inhibit or at least partially prevent the movement of the seal body when the bridging portions  230  move, such as movement caused by movement of the facial pads  250 . The movement of the bridging portions  230  are further described elsewhere herein. The reinforcing element may have any suitable shape or form, but the reinforcing element preferably provides sufficient stiffness such that it can prevent the seal body from folding, collapsing or buckling. 
     The reinforcing element may be positioned such that the reinforcing element does not contact the user when the mask is applied to the user. For example, the reinforcing element may be positioned at the anterior, non-patient facing side of the seal body, and/or within an interior space of the seal body. In some embodiments, the reinforcing element may be constructed from the same material as the seal body, but as a thickened portion. In some embodiments, the reinforcing element may be constructed from a different material than the seal body. In some embodiments, the reinforcing element may be formed integrally with the seal body (e.g. overmoulded). In some embodiments, the reinforcing element may be formed as a separate structure with the seal body and attached or otherwise installed to the seal body (e.g., removably or non-removably attached). The reinforcing element may be placed on the outer surface of the seal body, on the internal surface of the seal body, or within the seal body. The reinforcing element may be placed on an upper, lower, side portion, or any suitable location of the seal body. 
       FIGS. 6A-D  illustrates a reinforcing element  226  placed within the seal body  210 . As illustrated in  FIGS. 6A-D , in one embodiment, the reinforcing element  226  has an elongate shape. In some embodiments, the reinforcing element  226  may extend at least partially across the width of the seal body  210 . In some embodiments, the reinforcing element  226  may extend along the entire width or substantially the entire width of the seal body  210 , from one side end to the other side end. In some embodiments, the reinforcing element extends from a portion of the seal body  210  where the seal body  210  connects with one of the bridging portions  230  to a portion of the seal body  210  where the seal body  210  connects with the other one of the bridging portions  230 . As a result, the reinforcing element may maintain a general shape or width dimension of the seal body  210  or inhibit or prevent the seal body  210  from collapsing when the bridging portions  230  move toward the center of the seal body  210 . In some embodiments, the reinforcing element  226  may be positioned along the lower portion of the seal body  210 , such that the reinforcing element  226  does not interfere with rolling movement of the upper portion  212  described elsewhere herein or causes less interference than a position closer to or within an upper portion of the seal body  210 . 
       FIGS. 7A-7C  illustrate a reinforcing clip  710 , which is another example of the reinforcing element. In some embodiments, the reinforcing clip  710  has a substantially elliptical shape when viewed from the front. The reinforcing clip  710  is sized and shaped to fit externally over an anterior, non-patient side of the seal body. In some embodiments, the reinforcing clip  710  may be positioned internally within the mask cavity  260 .  FIGS. 8A-C  illustrate a seal body  810  which can receive the reinforcing clip  710 . In other respects, the seal body  810  can be the same as or similar to the seal bodies  210  and  510  described herein. The seal body  810  may include a receiving portion  820  designed to receive the reinforcing clip  710 . For example, as illustrated in  FIGS. 8A-C , an anterior, non-patient side of the seal body  810  is contoured to fit with the shape of the reinforcing clip  710 . In some embodiments, the clip  710  can be removably coupled to the seal body  810 , such that the clip  710  can be easily removed or replaced. In some embodiments, the reinforcing clip  710  may be attached to the seal body  810  by snap fitting or interference fitting. In some embodiments, the clip  710  may be fixedly attached to the seal body. In some embodiments, the clip  710  may be attached to the seal body by an adhesive. In some embodiments, the reinforcement clip  710  may be made of a stiffer material than the seal body.  FIGS. 9A-D  illustrate a patient interface  900  including the reinforcing clip  710 . As shown in  FIGS. 9A-9D , the reinforcing clip  710  may extend substantially around a front portion of a seal body  940 . 
       FIGS. 8A-C  further illustrate a single opening  815  which could be used to attach the one or more tubes, such as a coaxial tube, or two (or more) interface tubes (as described above) pre-assembled into a unitary connector for attachment to the opening. 
       FIGS. 10A-B  illustrate another mask  1000  including a seal body  1010 . The mask  1000  can be substantially similar to the other masks described herein. Accordingly, features of the mask  1000  not described in detail can be the same as or similar to corresponding features of the other masks described herein, or can be of another suitable arrangement. Moreover, features of the mask  1000  can be utilized with the other masks described herein. The mask  1000  also includes a reinforcing clip  1020  as the reinforcing element. The reinforcing clip  1020  may be similar to the reinforcing clip  710 , except that the reinforcing clip  1020  is integrally formed with the bridging portions  1030 , such that the reinforcing clip  1020  extends towards or to the facial pads  1050 . In some embodiments, the reinforcing clip  1020  and the bridging portions  1030  are made of the same material and can be an assembly or a unitary structure. In some embodiments, the reinforcing clip  1020  is thicker and the bridging portions  1030  are thinner, such that the reinforcing clip  1020  is stiffer than the bridging portions  1030 . In other embodiments, the reinforcing clip  1020  can be made of a stiffer material than the bridging portions  1030 . 
     In some embodiments, the seal body  1010  may not include a separate or distinct reinforcing element. In some such arrangements, certain regions of the seal body  1010  may be thickened, hardened or otherwise structured to reinforce the seal body  1010 . For example, in some embodiments, a tube-receiving portion  1015  of the seal body  1010  and/or the end of the interface tubes is thickened or hardened and may function as the reinforcing element or in a manner similar to the reinforcing element. In some embodiments, the tube-receiving portion  1015  and/or a portion of the seal body  1010  adjacent to or surrounding the tube-receiving portion  1015  defines a reinforced region  1026  that is thicker, harder or otherwise reinforced relative to other regions of the seal body  1010 , such that the reinforced region  1026  is stiffer than other regions of the seal body  1010 . In some embodiments, the tube-receiving portion  1015  can be made of a stiffer material than other regions of the seal body  1010 . In the illustrated arrangement, the reinforced region  1026  corresponds with a portion of the seal body  1010  bounded by the reinforcing clip  1020 . With such an arrangement, the reinforced region  1026  of the seal body  1010  can assist the reinforcing clip  1020  in maintaining a desired shape of the seal body  1010 . In other configurations, the reinforced region  1026  of the seal body  1010  can be configured to provide some or all of the desired reinforcement of the seal body  1010  such that the clip  1020  can be made more flexible, such as to reduce material costs and/or ease assembly. 
     Securement System 
     As illustrated in  FIGS. 2A-D  and  6 A-D, the mask  200  includes a plurality of contoured backings or facial pads  250 , which can rest on a user&#39;s face. The illustrated embodiment of the mask  200  includes a pair of the backing or facial pads  250 , but in some embodiments, the mask  200  includes three or more backing or facial pads  250 . For example, as shown in  FIGS. 21A-D , the mask  2200  may include a third backing or facial pad  2250  which can rest on the forehead area of or elsewhere on the user, in addition to the pair of backing or facial pads  2250  which rest on cheeks of the user&#39;s face. The backing or facial pads  250  may be connected to the end of the bridging portions  230 . As illustrated in  FIGS. 2A-D  and  6 A-D, each of the bridging portions  230  may terminate into the base or connecting portion  235  of the backing or facial pad  250 . In some embodiments, the backing or facial pad  250  can receive and support one or more layers of the patch (e.g. a user interface patch or a dermal patch) or adhesives, such that the backing or facial pad  250  can rest on the user&#39;s face without directly contacting the user&#39;s skin when the user interface is secured on the user&#39;s face. The connection mechanism of the backing or facial pad  250  and the patches or adhesives is described in further detail elsewhere herein. In alternative arrangements, the backing or facial pad  250  can be connected to a headgear and/or a chinstrap for the securement of the mask  200  or the mask  200  can be otherwise connected to a headgear and/or a chinstrap, which are common components known in the art. 
     The backing or facial pads  250  may be pre-formed to be of a contour that is substantially curved to fit a user&#39;s face, cheek or upper lip region. In some embodiments with a point of contact in the forehead region, the contour could be selected to match or accommodate the contour of the user&#39;s forehead, which may be the same as, flatter, or more curved than a cheek region, for example. The enlarged end of the bridging portions  230  may be also contoured to accommodate the contour of the facial pads  250 . The facial pads  250  may be anatomically shaped with a distribution and scale of curvature that reflects the facial geometry of the intended user. The anatomical shape of the facial pads  250  can give the interface a positive engagement with a user&#39;s face at a predetermined position where the contour of the facial pads  250  matches the user&#39;s facial contour. Pre-shaping or contouring the facial pads  250  to the user&#39;s facial features reduces the pressure applied to the user&#39;s face by any retention mechanism (adhesive tape, headgear or other means). This reduces the likelihood of pressure sores, head forming, or other injury. The positive engagement promoted by the anatomical shape of the facial pads  250  increases the stability of the mask  200  and therefore improves comfort and efficacy of the treatment being administered. 
       FIGS. 21A-21D  illustrate an embodiment of a mask  2200  with a third backing or facial pad  2250 , configured to contact the patient&#39;s forehead region. As per the backing or facial pads  250  configured to rest on cheeks of the user, the backing or facial pad  2250  may be connected to the end of a bridging portion  2230 . The bridging portion  2230  may terminate into a base or connecting portion  2235  of the backing or facial pad  2250 . In some embodiments, the backing or facial pad  2250  can receive and support one or more layers of the interface patch or dermal patch, or adhesives, such that the backing or facial pad  2250  can rest on the forehead without directly contacting the skin. The connection mechanism of the backing or facial pad  2250  and the patches or adhesives can be the same as that of the backing or facial pads  250  arranged to lie on the cheeks, which is described in further detail elsewhere herein. The third backing or facial pad  2250  and bridging portion  2230  in conjunction with the associated interface patch/dermal patch/adhesives can provide vertical stability to the mask while positioned on the patients face and can assist in maintaining the mask seal in use. The third backing or facial pad  2250  and/or bridging portion  2230  can be fixed to or integrally formed with the mask  2200 . Alternatively, the third backing or facial pad  2250  and/or bridging portion  2230  can be removably attached to the mask  2200 . For example, the bridging portion  2230  may attach to the mask  2200  by a suitable fastener or may be removed by tearing or cutting the bridging portion  2230  from the mask  2200 . 
     The patient interface may be secured to the patient&#39;s face using a securement system. The securement system may include a two-part releasable attachment or connection arrangement. The two-part releasable attachment or connection arrangement may be a two-part releasable attachment or connection arrangement as described in PCT application PCT/NZ2011/000218, published as WO2012/053910, the contents of which are incorporated herein by reference. The reference herein to a patient interface, patient interface patch, and similar terms, will be understood to be similar to the reference to a user interface or user interface patch in WO2012/053910. Such two-part releasable attachment or connection arrangement enables securement of the patient interface without use of a headgear or a bonnet, thereby preventing potential head forming by the headgear or the bonnet on babies or young children with still-developing skull structure and/or active fontanelles. The releasable connection arrangement includes a pair of patches that are affixed to the patient and the patient interface, respectively. The first patch is a dermal patch that is adhered or otherwise attached to the patient&#39;s skin. The dermal patch has a user side that faces the user&#39;s skin and an interface side that faces the patient interface. The user side of the dermal patch may be attached to the skin of a user by a dermatologically sensitive adhesive, such as a hydrocolloid. The patient interface side of the dermal patch is provided with the first part of the two-part releasable attachment or connection system. 
     The second patch is a patient interface patch. The patient interface patch also has a patient side and an interface side. The patient side of the patient interface patch is disposed adjacent the dermal patch when the system is engaged. The complimentary second part of the two-part releasable attachment or connection system is affixed to the patient side of the patient interface patch so that the respective parts of the two-part releasable attachment or connection system are easily engageable when the patches are brought together. The interface side of the patient interface patch is affixed to the patient interface (e.g. at the backing or facial pads  250 ). The patient interface patch may be integrated with, formed integrally with (i.e., by overmolding or other methods as are known in the art), or suitably adhered to the patient interface. 
     The two-part releasable attachment or connection arrangement may comprise a mechanical fastener, such as a hook and loop material (such as VELCRO™), a magnet (or ferrous material to attract with a magnet) or an array of magnets disposed on the respective patches with the poles suitably arranged, an adhesive arrangement that is activated when the patches are urged together or another suitable releasable coupling. The interface side of the dermal patch may have one of a hook or a loop material, and the patient side of the patient interface patch may have the other of the hook or loop material, such that the dermal and patient interface patches are releasably attachable or connectable to each other. 
     Turning back to  FIG. 2D , a rear surface  252  of the facial pad  250  can be initially provided without a patient interface patch, i.e., the surface  252  can receive or retain a patient interface patch. Such a patient interface patch may be connected to the rear surface  252  by an adhesive or other suitable connection as is known in the art (such as by hook-and-loop fastener, ultrasonic welding, and/or co-moulding or overmoulding). Once the patch is in position, it is ready to be connected to or receive a dermal patch. Alternatively, the patient interface patch may be assembled to the rear surface  252  of the facial pad  250  in the same operation as molding the facial pad  250 . Embodiments with a third facial pad  2250  may be similarly provided with a two-part releasable attachment or connection arrangement such as that described above. 
     In some situations, a chinstrap may be used in conjunction with the two-part releasable attachment or connection arrangement. This chinstrap may be a standard or conventional chinstrap that is used to keep the patient&#39;s mouth closed during CPAP therapy. The chinstrap helps ensure a sealed system (by biasing the patient&#39;s mouth closed or substantially closed for eliminated, or at least reduced, mouth leak) and thus more effective treatment. In some embodiments, the chinstrap may be a part of a headgear or connected to the headgear which can be secured around the patient&#39;s head. 
     Additionally, or alternatively, a chinstrap may be part of the patient interface and may be used without a two-part releasable attachment or connection arrangement to secure the device. 
     In one example embodiment, the chinstrap comprises a material that is soft on the patient&#39;s face. Advantageously, the material may also be a stretchable fabric, such as a knit fabric, or a fabric comprising elastic material or elastic fibres. The chinstrap may have one or more regions of hook or loop material/fasteners, and/or may be substantially made up of or covered by hook or loop material. In one preferred embodiment, this is loop material, which is soft on the patient&#39;s face. In another example, this may be a hook material, so that any overlap of the user interface patch over the footprint of the strap does not cause any damage or scratching of the patient&#39;s face due to hooks on the interface patch. In an embodiment, the strap includes at least one region of hook material, and at least one region of loop material. The chinstrap may connect to a region of hook or loop fasteners on a connecting portion on the patient interface (e.g., the patient interface patch). This securement system secures the patient interface on the patient&#39;s face without having to apply any adhesive to the face. In one example embodiment, the chinstrap is used in combination with a continuous loop headgear that extends around the back and/or top of the patient&#39;s head. In a further example embodiment, the chinstrap comprises a slit or bifurcation to allow it to conform to the patient&#39;s curved chin region. In one embodiment, the chin strap may comprise, or may additionally comprise, an opening, slit, or bifurcation to hold a nasogastric or endotracheal tube. 
     The securement system may include a bonnet, such as an adjustable bonnet, which may include one or more sections of loop material. In some embodiments, the patient interface patch may be connected to the adjustable bonnet using a suitable structure, such as buttons, snaps, adhesive, magnets, ties, elastic, or other mechanical attachments. In some embodiments, the chinstrap may be attached to the bonnet via hook or loop fasteners. In some embodiments, the hook or loop fasteners on the bonnet or the chinstrap are movable or the bonnet or the chinstrap includes multiple hook or loop fasteners, such that the position where the patient interface or tube is secured on the bonnet or the chinstrap can be changed or adjusted as desired by the user or the clinician. 
     Furthermore, instead of extending over the chin, in one embodiment the at least one headgear strap may extend down the side of the patient&#39;s cheek. This type of strap may again comprise hook or loop material to attach to the patient interface and also to the bonnet (in an embodiment where the side strap portions and bonnet are not integral). In one preferred embodiment, this is loop material to be soft on the patient&#39;s face. In another example, this may be hook material, so that any overlap of the user interface patch over the footprint of the strap does not cause any damage or scratching of the patient&#39;s face due to hooks on the interface patch. In one embodiment, the strap comprises at least one region of hook material, and at least one region of loop material. An embodiment of these side strap portions may attach to the bonnet. The strap may have a longitudinal body that extends down the side of the patient&#39;s cheek. 
     Further examples of the securement system and its components are further described in PCT application PCT/NZ2011/000218, published as WO2012/053910, the contents of which are incorporated herein by reference. 
     Structure and Movement of the Bridging Portions 
     As described herein, the facial pads (e.g. the facial pads  250 ) can rest directly or indirectly on a user&#39;s face when the mask (e.g. the mask  200 ) is worn by the user. Accordingly, the bridging portions (e.g. the bridging portion  230 ), which is connected to the facial pads, may be moved or deflected when the user&#39;s face moves. For example, when a portion of the user&#39;s face where the facial pads rest on moves, such external force or movement may be conducted to the bridging portion, and to the seal body (e.g. the seal body  210 ) eventually. In some instances, the bridging portions themselves may move or deflect when an external force is exerted on them. For example, the user of the mask may lay on the bridging portions, exerting force to the bridging portions, and thus to the seal body. Accordingly, it is desirable for the bridging portion to be constructed such that the seal body can maintain its seal with the user&#39;s face even when the user&#39;s face and/or the facial pads move. 
       FIG. 11  illustrates the mask  200  positioned on a user&#39;s face. As illustrated, the bridging portions  230  may be constructed to have a first configuration (shown in solid line), which may be a relaxed or neutral configuration. In the first configuration of the bridging portions  230 , the facial pads  250  are located in a first or neutral position (A). The bridging portions  230  are movable within a range of adjustment from the relaxed first configuration toward or to a second configuration (shown in dashed line), which may be a deformed or deflected configuration. In the second configuration of the bridging portions  230 , the facial pads  250  are located in a second or adjusted or deflected position (B), which may be closer to the user&#39;s face than the first position (A). The second position (B) may place the facial pads  250  on the user&#39;s face (e.g., opposing cheek regions and/or an additional forehead region). 
     To apply the mask  200  to the user, the seal body  210  may be first positioned on the face of the user, such as on the user&#39;s nose as described herein with reference to  FIG. 4 , for example. With the bridging portions  230  in the first configuration and the facial pads  250  in the first position (A), the facial pads  250  may be spaced away from the user&#39;s face. With the seal body  210  positioned on the user&#39;s face, the facial pads  250  may be moved from the first position (A) toward the face of the user and toward or to the second position (B) until the facial pads  250  contact or rest upon the user&#39;s face. As described above, movement of the facial pads  250  from the first position (A) toward or to the second position (B) will likely cause movement (e.g., flexing or extension) of the bridging portions  230 . The facial pads  250  can be secured to the user&#39;s face directly or indirectly by an external force, such as using an adhesive connection, a headgear arrangement, a two-part connection arrangement as discussed above, or another suitable support structure, such as any of those described herein. 
     When the facial pads  250  and the bridging portions  230  are in position (B) illustrated in  FIG. 11 , the bridging portions  230  preferably generate a force tending to apply downward pressure (in the orientation of  FIG. 11 ) to the seal body  210 , which helps create or maintain a seal between the seal body  210  and the user. The force is generated as a result of deformation of the bridging portions  230  from their first or relaxed configurations and the resulting material strain tending to revert the bridging portions  230  back towards their first or relaxed configurations. 
     Advantageously, if the first configuration of the bridging portion  230  spaces the respective facial pad  250  away from the user&#39;s face in position (A) as illustrated in  FIG. 11 , the user or a clinician is provided with the freedom to fit and position the facial pads  250  on the user&#39;s face as desired. Such an arrangement facilitates adjustment or customization of the fit of the mask  200 . For example, extending or deforming the bridging portions  230  in an outward direction before securing the facial pads  250  increases the downward force acting on the seal body  210  in comparison to simply move the facial pads  250  straight towards the user&#39;s face. The bridging portions  230  may be constructed to limit downward force to an acceptable level to inhibit or prevent the user or the clinician from overtightening the mask  200  by way of overextension of the bridging portions  230 , while retaining some adjustability to reduce, eliminate or otherwise address leaks that may occur. 
     In some configurations, the deformable configuration of the bridging portions  230  provides some degree of de-coupling of the facial pads  250  from the seal body  210 , preferably while maintaining the downward force on the seal body  210  toward the face of the user. For example, deformation of the bridging portions  230  may allow cheek movement of the user to have a reduced or minimal effect on the downward pressure between the seal body  210  and the bridging portions  230  in comparison to a straight or substantially straight bridging portion. Preferably, the deformation of the bridging portions  230  at least reduces or possibly eliminates disruption of the seal between the seal body  210  and the user&#39;s face as a result of cheek movements of the user&#39;s face. 
     Some or all of these advantages may be provided by the shape of the bridging portions  230 , the orientation of the bridging portions  230  or the material(s) used to construct the bridging portions  230 . In some embodiments, the bridging portions  230  may be made of a flexible or elastically-deformable material, such that at least a portion of a length of the bridging portion  230  has flexibility and/or elasticity. In some embodiments, the bridging portions  230  are each shaped such that its curved geometry facilitates the flexibility of the bridging portions  230 . The flexibility of the bridging portions  230  preferably allows the bridging portions  230  to absorb forces exerted on them, for example caused by the movement of the user&#39;s cheek. Accordingly, as described above, only some of the force exerted on the facial pads  250  and, thus, the bridging portions  230  is transferred to the seal body  210 . Advantageously, such an arrangement assists in maintaining the seal between the seal body  210  and the user&#39;s face during movement of the user&#39;s cheeks. 
     As illustrated in, for example,  FIG. 2B  and  FIG. 11 , the bridging portions  230  may be provided as elongate arms shaped to have or define a non-linear, circuitous or serpentine path  300  between a first location or first end  302  at a junction between the seal body  210  and the bridging portion  230  and a second location or second end  304  at a junction between the bridging portion  230  and the base  235  of the associated facial pad  250 . In some configurations, the bridging portions  230  each define an S-shape as viewed from above. The path  300  can be defined by a geometric center of the bridging portion  230  along its length. Following the path  300  from the first end  302  to the second end  304 , the path  300  preferably defines at least a forwardly-extending portion followed by at least an outwardly or rearwardly-extending portion relative to the overall mask  200  wherein a forward direction is toward the front of the mask or away from the user and the rearward direction is toward the rear of the mask or toward the user. In addition, although discussed in terms of the path  300 , it will be understood that the references to the orientation of the path  300  equally apply to the orientation of the bridging portion  230  itself. Thus, any reference to the path  300  can be replaced with a reference to the bridging portion  230 . 
     In the illustrated arrangement, the path  300  has an initial outward trajectory when moving along the path  300  in a direction from the first end  302  toward the second end  304 . The path  300  then extends in a substantially forward direction. In some configurations, the initial outward trajectory can be omitted and the path  300  can initially extend in a substantially forward direction from the first end  302 . In the illustrated arrangement, the path  300  continues in a forward direction while moving inwardly toward a centerline  306  of the mask  200 . The path  300  then moves outwardly away from the centerline  306  while still moving in a forward direction. The illustrated path  300  then reverses course and moves rearwardly. In addition, the path  300  also moves outwardly away from the centerline  306  while moving rearwardly to the second end  304 . Overall, the illustrated path  300  extends greater in a forward direction than in a rearward direction, thereby the second end  304  of the illustrated path  300  is positioned at least partially forwardly than the first end  302 . Accordingly, an imaginary straight line extending from the first end  304  to the second end  302  forms an angle  308  smaller than 90°. In some embodiments, the angle  308  can be between about 30°-80° inclusive, and including any and all values within this range (such as about 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°). However, the angle  308  can be changed when the bridging portions  230  are extended or deformed. For example, at the second or adjusted or deflected position (B) of  FIG. 11 , the angle  308  can be equal or greater than 90°. 
     Thus, the illustrated path  300  changes direction at least once in a fore-aft direction or a direction along the centerline  306  (e.g., moves forwardly and then moves rearwardly). Preferably, the path  300  also changes direction at least once in a direction toward and away from the centerline  306 . In particular, the illustrated path  300  changes direction twice in the direction toward and away from the centerline  306  (e.g., moves away from, then toward and then away from the centerline  306 ). 
     Such an arrangement increases the length of the path  300  or the effective length of the bridging portion  230 , in a space-efficient manner, thereby lessening the bulkiness of the mask  200  and improving the comfort of the user. A greater effective length of the bridging portions  230  can provide the bridging portions  230  a greater range of movement or adjustment, such that the mask  200  can be applied to users with a wider range of face sizes. In addition or in the alternative, a greater effective length provides the bridging portions  230  with a flatter force-extension curve, which may inhibit or prevent the seal body  210  from exerting too much force on the user&#39;s face even when the bridging portions  230  are significantly stretched while in use. A flatter force-extension curve provides a more constant sealing force on a patient&#39;s face during cheek movement. 
     In some configurations, the effective length of the bridging portion  230  or length of the path  300  is significantly greater than one or both of a linear distance  310  between the first end  302  and the second end  304  of the bridging portion  230  and a lateral distance  312  between the first end  302  and the second end  304  of the bridging portion  230  (in a direction perpendicular to the centerline  306 ). In general, the larger the ratio between the effective length or length of the path  300  and the linear distance  310  or lateral distance  312 , the larger the adjustment range, the flatter the force-extension curve and/or the greater the de-coupling of movement between the facial pads  250  and the seal body  210 . In some embodiments, each of the bridging portions  230  may have a length or arclength (length of the path  300 ) of between about 150%-300%, inclusive, and including any and all values within this range (such as about 170%, 175%, 200%, 210%, 225%, 250% or 275%), of either of the linear distance  310  or the lateral distance  312 . In some embodiments, ratio of the length of the path  300  to either of the linear distance  310  or the lateral distance  312  can be greater. 
     As shown in  FIGS. 2B, 6B and 11 , the bridging portions  230  may have a relatively gentle curve/radius. In some such configurations, the bridging portions  230  roll in and out, in contrast to folding like a hinge, during movement. In some embodiments, the bridging portions  230  have a radius of curvature  320  of between about 0.5 cm-30 cm, inclusive, including any value within this range, such as about 0.75 cm, 1 cm, 2 cm, 5 cm, 10 cm, 15 cm, 20 cm, 25 cm or 30 cm, at any location along the length of the bridging portion  230 . In some embodiments, the radius of curvature  320  can be greater. In some embodiments, each of the bridging portions  230  may have substantially constant or smoothly varying curvature throughout its length, such that the bridging portions  230  do not include an abruptly bent or folded point. In some embodiments, each of the bridging portions  230  may have at least partially an elliptical shape, a circular shape, a hook shape, a U-shape, or an S-shape as viewed from above or below the mask  200 . In some embodiments, as shown in FIGS,  2 B,  6 B and  11 , each of the bridging portion  230  may have a portion curved inward relative to the seal body  210 , and portion curved outward relative to the seal body  210 . In some embodiments, the bridging portions  230  may have an at least partially circular or elliptical cross-section. 
     In some embodiments, the bridging portions  230  may be made of a flexible material, such that the bridging portions  230  are flexible or deformable, as described above. In some embodiments, the bridging portions  230  may be made of the same material as the seal body  210  in an assembled or unitary construction. In some embodiments, the bridging portions  230  may be made of one or more elastomer materials, such as silicone, rubber, polyethylene, etc. In some embodiments, the bridging portions may be made of a single material. In some embodiments, the bridging portions  230  may be made of two or more materials, such that a region of the bridging portion  230  has a different flexibility relative to another region. 
     In some embodiments, each of the bridging portions  230  may be shaped such that its geometry contributes to the flexibility. In some embodiments, the bridging portions  230  may have a constant or substantially constant cross-sectional area throughout their length. In some embodiments, the bridging portions  230  may have a varying cross-sectional area along their length, such that, for example a region of the bridging portion  230  has greater cross-sectional area and, assuming the same material, is stiffer than another region. 
     In some embodiments, as illustrated in  FIG. 11 , each of the bridging portions  230  is attached to the seal body  210  separately, thereby allowing movement independent from each other. For example, when one cheek and thus one facial pad  250  and one bridging portion  230  are moved (e.g. when the user is lying on his side or when the user&#39;s face is squeezed), the other bridging portion  230  may not move, and a sufficient seal may be maintained. In other embodiments, such as shown and described with reference to  FIG. 20 , for example, the bridging portions  230  may be connected to one another, which may provide additional rigidity where desired in comparison to fully independent bridging portions  230 . 
     Other configurations of bridging portions are also possible, many of which share some or all of the characteristics and/or provide similar functionality as described above. For example, the mask  1000  illustrated in  FIGS. 10A-B  includes bridging portions  1030  connected to the reinforcing clip  1020 . The mask  1000  further includes facial pads  1050  attached to the bridging portions  1030 . The facial pads  1050  may be similar to the facial pads described elsewhere herein, such as the facial pads  250 . The bridging portions  1030  can have an overall curvature in a relaxed position that creates a substantially longer effective length relative to the linear distance or lateral distance. In the illustrated arrangement, each of the bridging portions  1030  changes direction at least twice in a fore-aft direction. For example, the bridging portions  1030  each extend rearwardly, forwardly and then rearwardly moving from an end adjacent the seal body  1010  to an end adjacent the facial pad  1050 . In the illustrated arrangement, the bridging portions  1030  move continuously outwardly from the end adjacent the seal body  1010  to the end adjacent the facial pad  1050 ; however, changes in direction could also occur in this direction. 
     As described with regard to the mask  200 , forces may be exerted to the facial pad  1050  and the bridging portions  1030 , for instance, when the patient is lying on the side of his or her face or when the patient&#39;s face is squeezed. When such forces are exerted on the facial pads  1050 , the bridging portions  1030  are inclined to fold inward at the hinges  1032 , labeled in  FIG. 10B . Such inward bending of the bridging portions  1030  at the hinges  1032  may press the seal body  1010  toward the user. The bending of the bridging portion hinge  1032  can be limited by the patient&#39;s anatomy. A variety of hinge types can be used for the hinges  1032 . The hinges can bend in a predictable, limited number of directions to define the mechanical behavior of the dynamic interface. 
     In some embodiments, a strap may be used in place of the bridging portions. The strap may be integrally formed with the seal body, or may be a separate piece and can be attached to the seal body. In some embodiments, the strap may have regions of hook or loop material for securing the mask to the securement system described elsewhere herein. In some embodiments, the strap can be made of, or covered in, fabric or a fabric/foam laminate such as neoprene or breath-o-prene. 
     Tube Attachment and Positioning 
       FIGS. 12A-E  illustrate a mask  1300  including a seal body  1310 , bridging portions  1330 , and facial pads  1350 . As shown in  FIGS. 12B-E , the mask  1300  may also include a reinforcing element  1380  similar to the reinforcing element  226 . The mask  1300  and its components can be the same as or similar to the masks and their corresponding components disclosed elsewhere herein, such as the mask  200  or  1000 , except as described below. In some embodiments, the seal body  1310  includes two tube extensions  1340  as shown in  FIGS. 12A-E . Each of the tube extensions  1340  extends from a seal end  1344  adjacent the seal body  1310  toward a tube end  1342  away from the seal body  1310  in a direction away from the user&#39;s face when the mask  1300  is worn. The tube extensions  1340  can connect interface tubes to the seal body  1310 , allowing gas flow from and to the user. 
     In some embodiments, the tube extensions  1340  may be integrally formed with the seal body  1310 . In some embodiments, the tube extensions  1340  may be connected to the seal body  1310 . The seal body  1310  may include openings at the front portion, such that the tube extensions  1340  can be connected at the openings. In some embodiments, each of the seal ends  1344  may have elliptical or circular shape. In some embodiments, the tube extensions  1340  may be removably attached to the seal body  1310 , such that the tube extensions  1340  can be attached or removed as desired. When the tube extensions  1340  are removed, the seal body  1310  may have a tube-receiving portion such as the tube-receiving portion  214 , such that the seal body  1310  can receive interface tubes. In some embodiments, the seal end  1344  can be connected to the seal body  1310  at the tube-receiving portion. In some embodiments, the seal end  1344  can be connected to the seal body  1310  by suitable connection mechanisms, such as friction-fitting, snap-fitting, screw-fitting or barbed connections. The connection between the seal end  1344  and the seal body  1310  preferably is sealed such that the gas passing to or from the seal body  1310  does not leak. 
     The tube end  1342  of each of the tube extensions  1344  can be connected to any suitable interface tubes. In some embodiments, the interface tubes are breathable, being permeable to water vapor while being impermeable to liquid or bulk flow of gases. Further examples of interface tubes which can be used with the patient interfaces described herein are described in U.S. patent application Ser. No. 15/514,221, published as U.S. 2017/0304578, the contents of which are incorporated herein by reference. In some embodiments, an adaptor or connecter may be placed between the tube end  1342  and the interface tube, such that various interface tubes can be connected to the tube extensions  1340 . The tube extensions  1340  may be removably attached to the interface tubes by any suitable connection mechanisms, for example friction-fitting, snap-fitting, interference-fitting, screw-fitting or barbed connections. 
       FIG. 12C  illustrates internal pathways of the tube extensions  1340  according to some embodiments. As shown in  FIG. 12C , the tube end  1342  of each of the tube extensions may include an inner flange  1343 . The inner flange  1343  can receive and hold the interface tubes in place. The connection between the tube end  1344  and the interface tube may be sealed such that the gas passing to or from the mask  1300  does not leak. 
     In some embodiments, each of the tube extensions  1340  taper towards the seal end  1344  and have a smaller diameter at a region adjacent the seal end  1344  than a region adjacent the tube end  1342 . In some embodiments, each of the tube extensions  1340  may taper away from the seal body  1310  and have a greater diameter at a region adjacent to the seal end  1344  than a region adjacent to the tube end  1342 . The tapered shape of the tube extensions  1310  may allow connection of larger interface tubes than what could be or is desirable for accommodated directly on the seal body  1310 . For example, interface tubes having a large diameter can be connected to a smaller mask via tube extensions  1340 . In other arrangements, the tube extensions  1340  may have a constant or substantially constant diameter throughout their length. In some embodiments, the seal end  1344  and the tube end  1342  of the tube extensions  1340  can have the same or substantially the same size and shape. 
     The tube extensions  1340  may be flexible such that the tube extensions can be moved or positioned or bent (without occluding) towards locating features which may be provided in the form of grooves  1332 . The flexibility of the tube extensions  1340  can facilitate comfort of the user and thereby facilitates more sleeping positions, and kangaroo care positions. At the same time, the tube extensions  1340  may have some structural integrity, such that the tube extensions  1340  do not collapse or kink in use. In some embodiments, the tube extensions  1340  may have ribs or supports internally and/or externally to prevent collapse while maintaining flexibility. 
     In some embodiments, to reduce the bulkiness of the patient interface, the tube extensions  1340  can be bent and placed at least partially along the bridging portions  1330 . In some embodiments, each of the bridging portions  1330  includes a locating feature, which in some embodiments is a groove  1332  extending at least partially along its front surface. The groove  1332  is configured to receive a portion of the tube extensions  1340 . In some embodiments, the bridging portions  1330  may further include cutouts  1334  at the groove  1332 . The tube extensions  1340  may be long enough to fit into the grooves  1332  and the cutouts  1334 . In some embodiments, the tube extensions  1340  are shorter, and interface tubes connected to the tube extensions  1340  are received in the groove  1332 . In some embodiments, the tube extensions  1340  or the interface tubes may further extend over a front, non-face side of the facial pads  1352 . In some embodiments, the front, non-face side  1352  of the facial pads  1350  include hook or loops which can receive hook or loops attached to the tube extensions  1340  or the interface tubes to retain them in a desired position. In some embodiments, the facial pads  1350  may include hook or loop material or adhesives on both sides (patient-facing and away-from-patient facing), such that the facial pads  1350  can be attached to the tube extensions  1340  or the interface tubes at one side, and the securement system described elsewhere herein on the other side. 
       FIG. 13  illustrates a mask  1400  similar to the mask  1300  described with regard to  FIG. 12  except that a tube extension  1440  includes one or more recessed portions  1442  with reduced wall thickness and stiffness for facilitating bending the tube extension  1440  without kinking. In the illustrated arrangement, the plurality of recessed portions  1442  are aligned with one another in a lengthwise direction of the tube extensions  1440 , but the recessed portions may be arranged to facilitate bending of the tube extensions  1440  in any desired directions. The tube extensions such as the tube extensions  1340  or  1440  may include any additional structure other than recessed portion, for facilitating bending without kinking or folding. 
     In some embodiments, the tube extensions  1440  can each include openings for venting of exhaust gases from the mask  1400 . For example, the openings can take the place of the recessed portions  1442 . The openings  1442  can form a bias flow vent, as is known in the art. In some configurations, the openings  1442  can also facilitate bending of the tube extensions  1440  in a manner similar to the recessed portions  1442  described above. In addition or in the alternative, a suitable vent arrangement can be provided on another portion of the mask  1400 , such as the seal body  1410 . 
     In some embodiments, the interface tubes may be connected to bridging portions, instead of being directly connected to the seal body or via the tube extensions.  FIG. 14  illustrates a mask  1500  having a seal body  1510 , bridging portions  1530 , and facial pads  1550 . The mask  1500  is similar to the masks described herein, such as the mask  200  or the mask  1300 , except as described below. 
     In some embodiments, each of the bridging portions  1530  includes or defines a substantially U-shaped portion as viewed from above. Preferably, the bridging portions  1530  are configured to provide similar functionality and one or more of the advantages of the other bridging portions described herein. For example, the bridging portions  1530  can generate a sealing force on the seal body  1510  in use. The bridging portions  1530  can provide at least some de-coupling of the facial pads  1550  from the seal body  1510 . Each of the bridging portions  1530  can define a path length or an effective length that is greater than a (e.g., lateral or linear) distance between the seal body  1510  and the associated facial pad  1550 . Such an arrangement can provide the bridging portion  1530  with a relatively flat force-extension curve, as described above. 
     In some embodiments, each of the bridging portions  1530  includes a tube receiving opening  1532  as illustrated in  FIG. 14 . Each of the bridging portions  1530  may further have an internal gas pathway  1534  connecting the tube receiving opening  1532  and a mask cavity of the seal body  1510 . The internal gas pathway  1534  may be connected to an internal opening (not shown) at the seal body  1510  such that the internal gas pathway  1534  fluidically connects the tube receiving opening  1542  to the mask cavity of the seal body  1510  while being internally located within the assembly of the bridging portions  1530  and the seal body  1510  along a portion or an entirety of its length. The tube receiving opening  1532  may be constructed such that the interface tube is connected to the bridging portion  1530  close to the user&#39;s face.  FIGS. 15A-B  illustrates the mask  1500  with the interface tubes  1630  attached to the bridging portions  1530 . By having an internal gas pathway and the interface tube  1630  connected closely to the user&#39;s face, the mask  1500  may be less bulky and provide increased comfort to the user. The interface tube  1630  may be connected to the tube receiving opening  1532  by any suitable mechanism, such as any mechanism described herein. For example, the tube receiving opening  1532  may have an inner flange and can receive a barbed insert of the tube  1630 . In some configurations, the barbed insert of the tube  1630  can be connected to the tube  1630  by overmoulding. 
     In some embodiments, the bridging portions  1530  may have overall contoured shapes as described with respect to the bridging portions  230 , but to accommodate the interface tube at the tube receiving opening  1532 , the bridging portions  1530  may have greater height along their lengths than the bridging portions  230 . In some embodiments, the bridging portions  1530  have a height substantially similar to the diameter of the tube receiving openings  1532 . In some embodiments, the bridging portions  1530  have a height greater than the diameter of the tube receiving opening  1532 . The bridging portions  1530  may have a substantially similar or smaller height than the seal body  1510 . At the same time, the bridging portions  1530  may have similar thickness with the bridging portions  230 , such that the bridging portions  1530  have laterally rolling movement of the bridging portions described elsewhere herein. Accordingly, the bridging portions  1530  may have a flatter cross-section than the bridging portions  230 . 
     The internal gas pathway  1534  may have small width/diameter, such that it does not interfere with the movement of the bridging portion  1530 . For example, the internal gas pathway  1534  may have a diameter of about 2 mm-1 cm or greater. As illustrated in  FIG. 14 , the tube receiving opening  1532  may include a raised portion to accommodate the diameter of the interface tube. At the same time, the bridging portions  1530  may have a certain degree of some structural integrity, such that they do not collapse or kink in use. In some embodiments, the bridging portions  1530  may have ribs or supports internally and/or externally to prevent collapse while maintaining flexibility. 
       FIG. 16A  illustrates a mask  1700  similar to the mask  1500  described in relation to  FIGS. 14-15B . The mask  1700  includes a seal body  1710 , bridging portions  1730 , and facial pads  1750 . In some embodiments, at least one of the bridging portions  1730  include a tube receiving opening  1732 . The bridging portions  1730  may be similar to the bridging portions  1530 , but the tube receiving opening  1732  may be defined in the bridging portion  1730  adjacent at a location where the bridging portion  1730  is connected to the seal body  1710 . The bridging portions  1730  may each further include one or more cutouts  1734  such that an interface tube may be passed through the cutout  1734  and connected to the tube receiving opening  1732  as illustrated in  FIG. 16B . The bridging portions  1730  may each include a clip  1736  which can removably retain the interface tube, such that the interface tube can be kept close to the user&#39;s face. The clips  1736  may isolate the mask seal from any forces that are exerted on the opposing end of the tubes. In some embodiments, the clip  1736  may be positioned at the facial pad  1750  or at the bridging portion  1730  adjacent the facial pad  1750 . In some embodiments, the bridging portion  1730  may include two or more clips  1736 . In some embodiments, the bridging portion  1730  may include tube retaining mechanism in addition to or alternative to the clip  1736 , for example, adhesive or a hook-and-loop fastener. 
     In some embodiments, a swivel connector, such as a swivel elbow, may be attached or overmoulded to the interface tubes to provide a connection (e.g., a curved connection) between the interface tube and a mask and to facilitate adjusting the position of the interface tube relative to the mask.  FIGS. 17A-B  illustrate such a swivel elbow  1800  separately from an interface tube or a mask. As shown in  FIGS. 17A-B , the swivel elbow  1800  may have a barbed end  1810  for being received by a corresponding inner flange of a mask, which can be similar to the internal flange  1343 . In some embodiments, the swivel elbow  1800  may have a threaded end  1820  for connection to an interface tube. In some embodiments, other mechanisms for connecting the swivel elbow  1800  and the mask or the interface tube, such as ultrasonic welding or overmolding, may be employed and the swivel elbow may have a suitable structure. 
       FIGS. 18A-D  illustrates the mask  200  with the swivel elbows  1800  attached to the openings  216 ,  218  of the tube receiving portion  214 . The swivel elbow  1800  may provide adjustment of positioning the interface tubes by swiveling around an axis or multiple axes (e.g., a ball-and-socket joint). The swivel elbow  1800  may reduce the bend radius of the interface tubes, thus ease the strain on the interface tubes when the interface tubes are bent and placed along the groove  233  of the bridging portions  230 . The swivel elbow  1800  may further allow the interface tubes to be directed up the patient&#39;s face (toward the top of their head) and attached to a headgear or bonnet, which may allow for easier side sleeping positions. Also, the swiveling of the swivel elbow  1800  may allow decoupling of the movement of the interface tubes from the mask, and help maintain a seal between the seal body  210  and the user&#39;s face when the tube is moved or bumped. The swivel elbow  1800  may be attached to any masks described elsewhere herein, such as the mask  1000 ,  1300 ,  1400 ,  1500 , or  1700 , to facilitate movement and guidance of the interface tubes. 
     In some embodiments, the connection between any of the interface tube, the mask, the tube extension, and the swivel elbow described in the specification may be permanent (e.g. overmoulded, attached by adhesive). Such permanent connection may be beneficial as it may withstand a stronger force. 
     Other Features of the Bridging Portions 
     As shown in  FIGS. 12A-E  and  18 A-D, any of the bridging portions described herein may have cutouts and/or grooves on the front/non-patient facing side to guide and accommodate the interface tubes when the interface tubes are placed to the sides, closer to the user&#39;s face. In this specification, a term “cutout” means any region of the bridging portions with a hole where all of the material of the bridging portion has been removed. A term “groove” means any region of the bridging portions that has been thinned by a depression in the surface. The size of the cutout, such as the cutout  1734 , may be larger than the diameter of the interface tube, such that the interface tube may pass through the cutout. Any bridging portion may have one or more grooves and/or cutouts. Hook or loop material may be positioned within the cutouts and/or grooves. The hook or loop material may attach to corresponding hook or loop material on interface tubes or tube extensions on the mask to aid with securement and positioning of these components. With cutouts and/or grooves, the interface tubes can be placed closer to the user&#39;s face, reducing the bulkiness of the patient interface. Further, cutouts and/or grooves may reduce the amount of material used for the bridging portions, thereby reducing costs and reducing the weight of the mask. Also, the cutouts and/or grooves may allow more clearance between the interface tubes and the bridging portions, such that the interface tubes are less likely to contact the bridging portions and interfere with the rolling movement of the bridging portions. 
     The cutouts or grooves may have any suitable shape, and be placed at any suitable region along the bridging portions and/or the facial pads. In some embodiments, as illustrated in  FIG. 19 , a mask  2000  may include cutouts  2032  extending along each of entire bridging portions  2030  and facial pads  2050 , thereby splitting the assembly of the bridging portion  2030  and the facial pad  2050  into an upper part  2030   a  ,  2050   a  and a lower part  2030   b ,  2050   b  . Such split of the bridging portion and the facial pad may allow independent movement of the upper part and the lower part, and independent adjustment of the upper part and the lower part. For example, if the mask is leaking gas into the user&#39;s eye region, the user or a clinician may adjust the top part. The upper part and the lower part of the bridging portion may independently move by rolling as described elsewhere herein. Additionally, such arrangement may provide greater stability as a result of spacing the upper part and lower part vertically from one another, thereby reducing rotation of the mask  2000  about the user&#39;s face. The mask  2000  may further include tube extensions  2040  which extend from a seal body  2010  and are positioned between the upper parts and the lower parts and can receive the interface tubes. 
       FIG. 20  illustrates a mask  2100  similar to the mask  2000 . The mask  2100  may include bridging portions  2130  and facial pads  2150  split into upper parts  2130   a  ,  2150   a  and lower parts  2130   b  ,  2130   b  . The bridging portions  2130   a  ,  2130   b  may extend from a center portion of a seal body  2110 , and the two bridging portions  2130   a  ,  2130   b  may adjacent one another without a tube extension located in between. In the illustrated arrangement, the bridging portions  2130  contact one another or are connected along a portion  2190 . Such an arrangement can provide additional stability to the combined bridging portions  2130 . In the illustrated arrangement, the split upper and lower parts  2130   a  ,  2130   b  of the bridging portions  2130  are located between the contacting or connected portion  2190  and the respective facial pads  2150 . 
     In some embodiments, each of the bridging portions  2130  includes or defines a substantially U-shaped or C-shaped portion as viewed from above. Preferably, the bridging portions  2130  are configured to provide similar functionality and one or more of the advantages of the other bridging portions described herein. For example, the bridging portions  2130  can generate a sealing force on the seal body  2110  in use. The bridging portions  2130  can provide at least some de-coupling of the facial pads  2150  from the seal body  2110 . Each of the bridging portions  2130  can define a path length or an effective length that is greater than a (e.g., lateral or linear) distance between the seal body  2110  and the associated facial pad  2150 . Such an arrangement can provide the bridging portion  2130  with a relatively flat force-extension curve, as described above. 
     Terminology 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to”. Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment. 
     The term “plurality” refers to two or more of an item. Recitations of quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics should be construed as if the term “about” or “approximately” precedes the quantity, dimension, size, formulation, parameter, shape or other characteristic. The terms “about” or “approximately” mean that quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics need not be exact, but may be approximated and/or larger or smaller, as desired, reflecting acceptable tolerances, conversion factors, rounding off, measurement error and the like and other factors known to those of skill in the art. Recitations of quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics should also be construed as if the term “substantially” precedes the quantity, dimension, size, formulation, parameter, shape or other characteristic. The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, in some embodiments, as the context may dictate, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than or equal to 10% of the stated amount. The term “generally” as used herein represents a value, amount, or characteristic that predominantly includes, or tends toward, a particular value, amount, or characteristic. For example, as the context may dictate, the term “generally linear” can mean something that departs from exactly parallel by less than or equal to 15°. 
     Numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also interpreted to include all of the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “1 to 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but should also be interpreted to also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3 and 4 and sub-ranges such as “1 to 3,” “2 to 4” and “3 to 5,” etc. This same principle applies to ranges reciting only one numerical value (e.g., “greater than 1”) and should apply regardless of the breadth of the range or the characteristics being described. 
     A plurality of items may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. Furthermore, where the terms “and” and “or” are used in conjunction with a list of items, they are to be interpreted broadly, in that any one or more of the listed items may be used alone or in combination with other listed items. The term “alternatively” refers to selection of one of two or more alternatives, and is not intended to limit the selection to only those listed alternatives or to only one of the listed alternatives at a time, unless the context clearly indicates otherwise. 
     Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavor in any country in the world. 
     The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features. 
     Where, in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth. 
     It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. For instance, various components may be repositioned as desired. It is therefore intended that such changes and modifications be included within the scope of the invention. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present invention. Accordingly, the scope of the present invention is intended to be defined only by the claims that follow.