Abstract:
A cervical collar comprising a neckband fabricated from a substantially incompressible plastic material and including a front body section having a first substantially flat shape and being bendable into a second substantially tubular shape, the front body section having a central portion, a laterally extending first side portion, and an opposed laterally extending second side portion. The cervical collar also includes a mandible support fabricated from a substantially and compressible plastic material comprising a centrally located chin support, a laterally extending first side portion, and an opposed laterally extending second side portion and a clip associated with the cervical collar which is moveable from a first unengaged position to a second engaged position in collaboration with a plurality of protrusions located on the cervical collar which define a plurality of predefined positions between the mandible support and the neckband.

Description:
This application claims the benefit of Provisional application No. 60/128,519 filed Apr. 9, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to orthopedic restraints and, in particular, to cervical collars. 
     THE BACKGROUND OF THE INVENTION 
     Light weight, plastic cervical collars come in a variety of designs. Traditional two-piece collars of the type shown in U.S. Pat. Nos. 3,756,226 and 4,886,052 use semi-circular body halves to provide cervical support. Despite their acknowledged successful performance, such two-piece collars are considered less desirable than other cervical collars for certain uses. In particular, such collars are considered undesirable for use in emergency vehicles where their relative bulk makes them difficult to store and because of the difficulties that arise from trying to slip a semi-circular rear collar half beneath the neck of an accident victim at the same time the emergency care providers are trying to immobilize the victim. 
     A number of cervical collars have been designed to respond to this need. These include, for example, those shown in U.S. Pat. Nos. 4,413,619; 4,712,540; 4,987,891; 5,060,637; and 5,215,517. Such collars typically include front and rear body sections cut from a non-foam, relatively stiff, yet flexible plastic sheet. A hybrid cervical collar is shown in U.S. Pat. No. 5,083,553 and has also been designed to respond to this need. The disclosed two-piece collar includes separate front and rear body sections cut from stiff, flexible plastic sheets. 
     The above-described collars are typically provided with an integrally attached chin support. This integrally attached chin support is mechanically fastened to the front body section, joining it at the distal ends at the chin support. However, the chin supports on such collars are typically provided as a flat structure, and must be folded into a cup-shape and mechanically fastened at the central portion of the folded front body section. This is due to the flat, resiliently flexible plastic sheet construction of the front body section and the chin support. Thus, these flat cervical collars with their mechanically attached chin support all suffer from a number of draw backs, especially with respect to the chin support area. In addition, these cervical collars are fabricated from stiff, flexible plastic sheets requiring that the chin support be mechanically fastened to the front body section. This mechanical fastening results in inadequate chin support, lack of stability, and decreased reliability. Due to the fabrication process used for existing collars, there is inadequate support under the chin. This inadequate support causes the head of the wearer to slip from the chin support into the interior of the collar. 
     At least one cervical collar has been designed to respond to this need. U.S. Pat. No. 5,622,529 discloses a substantially flat, one-piece and/or hybrid two-piece cervical collar having a unitary and/or molded central chin support. This unitary chin support design greatly simplifies the manufacturing process, simplifies the number of parts required, and reduces the mechanical fastening between the chin support and the front body section. The elimination of this mechanical connection decreases the flexibility of the collar and increases the rigidity of the chin support and results in a more stabilized cervical spine region of the wearer. It also results in a more reliable collar because the mechanical connection, which is prone to failure, could potentially break during continual use and may fail and render the collar useless. Also, the elimination of the mechanical connection between the chin and the collar decreases the manufacturing cost associated with providing such a connection and the manual labor required to accomplish the fastening process. 
     U.S. Pat. No. 5,622,529 also discloses, in FIG. 18, the use of a mandible support having a unitary chin cup is mechanically fastened to the front portion of the band of the collar. This embodiment of the &#39;529 patent shows that the improved unitary chin support and mandible can be used in conjunction with virtually any existing collar band design. 
     More recently, cervical collar manufacturers have begun to adopt the chin cup and mandible support design shown in U.S. Pat. No. 5,622,529. For example, U.S. Pat. No. 5,795,315 shows a cervical collar having a mandible support with a unitarily molded chin support. The mandible support is connected at its wing portioned to the front of the neck band. This simplified mandible support allows the cervical collar shown the &#39;315 patent to be manufactured with a simplified design and lower construction cost and allows the collar to adopt the height-adjustment features of the prior art collars to produce a multiple-size collar. The multiple-size cervical collar of the &#39;315 patent offers multiple sizes in a single collar and provides adequate support to the mandible as a result of the adoption of the unitarily formed chin support taught in U.S. Pat. No. 5,622,529. 
     Many prior cervical collars are known which include height-adjustment means for proper sizing of the collar. These include, for example, those shown in U.S. Pat. Nos. 5,728,054; 2,801,630; 2,911,970; 3,024,784; 3,285,244; 5,593,382; 3,916,885; and 3,060,930. Many of these collars employ height-adjustment means which are overly complex. Many of the designs include complex separately manufactured parts such as screws, bolts, pawls/ratchet teeth, snap connections, and hook and loop fasteners. Other height adjustment means, such as that shown in U.S. Pat. No. 5,795,315 also suffer from similar deficiencies. For example, the cantilevered protrusion of the &#39;315 patent readily disengages from the complementary openings formed in the neck band when the collar is around the patient&#39;s neck, resulting in a collar which is incapable of supporting the neck of the wearer. In addition, the adjustment means of the &#39;315 patent are spaced a significant distance from the center chin area of the collar and are located near the top edge of the collar, making adjustment of the collar on the patient&#39;s neck relatively difficult. In addition, the adjustment means of the &#39;315 patent does not allow for ready adjustability the height of the collar since the made protrusion cannot be disengaged with the complementary hole under normal circumstances when the collar is around the patient&#39;s neck, and must be removed from the neck to adjust the size thereof. Lastly, the height adjustment means of the &#39;315 patent requires a separate size indicating means which makes the sizing operation inconvenient. 
     Thus, there remains the need for a substantially flat, cervical collar having a height-adjustment means which is simple to use, does not require any complex manufacturing processes, does not readily disengage when the collar is bent around a patient&#39;s neck, and which includes an indicator for accurately sizing the collar. 
     SUMMARY OF THE INVENTION 
     The invention relates to a cervical collar having a neckband, a mandible support and a locking means. The neckband is fabricated from a substantially incompressible plastic material and comprises a front body section having a first substantially flat shape and being bendable into a second substantially tubular shape, the front body section has a central portion, a laterally extending first side portion, and an opposed laterally extending second side portion. The mandible support is fabricated from a substantially incompressible plastic material comprising a centrally located chin support, a laterally extending first side portion, and an opposed laterally extending second side portion. The locking means includes a clip associated with the cervical collar which is moveable from a first unengaged position to a second engaged position in collaboration with a plurality of protrusions located on the cervical collar which define a plurality of predefined positions between the mandible support and the neckband. 
     The plurality of protrusions may be formed on a face of the neckband and the clip is associated with the mandible support. 
     The neckband may have indicia disposed on the collar which indicate each of a plurality of collar sizes. 
     The protrusions may be formed in a pair of parallel columns on the front face of the neckband. 
     The clip may include at least one leg which engages between the protrusions to prevent relative motion or movement between the mandible support and the neckband. 
     The clip further may include a second leg which cooperates with a track formed on the collar to press the mandible support against the neckband to form a frictional fit there between. 
     A plurality of serrations may be formed on the adjacent faces of the mandible support and the neckband which engage each other and enhance the frictional fit between the mandible support and the neckband. 
     The clip may include at least one leg having an end which simulates a pointed arrow. 
     The clip may include an actuator head for facilitating the grasping of the clip by a user. 
     The clip may be fabricated so as to transfer the load of the user&#39;s chin on the mandible support to the neckband. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of an embodiment of a cervical collar made in accordance with the present invention. 
     FIG. 2 is a back view of the neck band of the present invention. 
     FIG. 3 is a front view of the mandible support of the present invention. 
     FIG. 4 is a back view of the mandible support of the present invention. 
     FIG. 5 is a front view of the neck band of the present invention. 
     FIG. 6 is a cross-sectional view of the neck band of the present invention taken along line VI—VI of FIG.  5 . 
     FIG. 7 is a front view of the U-shaped clip of the present invention. 
     FIG. 8 is a back view of the clip of the present invention. 
     FIG. 9 is a side view of the clip of the present invention. 
     FIG. 10 is a front view of an alternate embodiment of a cervical collar made in accordance with the present invention. 
     FIG. 11 is a back view of the cervical collar of FIG.  10 . 
     FIG. 12 is a partial enlarged isometric view of the front side of the cervical collar of FIG. 10 with clip in the unengaged position 
     FIG. 13 is a partial enlarged isometric view of the back side of the cervical collar of FIG. 10 with the clip in the unengaged position. 
     FIG. 14 is a partial enlarged isometric view of the front side of the cervical collar of FIG. 10 with clip in the engaged position. 
     FIG. 15 is a partial enlarged isometric view of the back side of the cervical collar of FIG. 10 with the clip in the engaged position. 
     FIG. 16 is a partial cross sectional view taken along line  16 — 16  of FIG.  11 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, in which like reference numerals identify like elements throughout the several views, there is shown in FIG. 1, a multiple size cervical collar  10  of the present invention. The collar comprises a neck band  12 , a mandible support  14 , foam padding  16 , and a fastener  18 . 
     The neck band  12  and mandible support  14  are preferably fabricated by a molding process, and most preferably injection molded in one piece from a lightweight, flexibly resilient, substantially incompressible material, such as a suitable thermoplastic resin. Some suitable thermoplastic resins include high density polyethylene, polyurethane, polypropane, or the like. 
     Neck band  12  has a length and flexibility sufficient to be wrapped into a tubular shape, with the free edge  20  adjoining the opposite free edge  22  so as to form the neck band  12  into a generally tubular shape. The neck band  12  is preferably bendable, and even flexible, but sufficiently rigid to provide cervical support when wrapped into the tubular shape. 
     The fastener  18  preferably comprises a first fastener  24  attached to free end  20  and a second fastener  26 , that cooperates with the first fastener  24 , attached at the free edge  22 . The fasteners  24  and  26  are coupled with and preferably fixedly attached by suitable mechanical or chemical means, such as adhesives, rivets, stitching, welding, integral molding, or the like, to the neck band  12 . The fastener  24  is most preferably a loop-type fabric fastening strip. The fastener  24  is preferably attached to the neck band  12  by rivet fasteners. The fastener  26  is most preferably a hook-type fabric fastening strip which is adhesively attached to the neck band  12 . 
     The flexible foam strips  16  are mounted to the inner face of the neck band  12  and the mandible support  14  and form the inner side of the collar  10  when it is wrapped into the tubular shape. The foam strips  16  are preferably shaped to cover the upper and lower portions of the front of the neck band  12  and the entire perimeter of the rear of the neck band  12 . The foam strips  16  are preferably permanently fixed to the inner side of the neck band  12  and the mandible support  14  by adhesives and/or mechanical fasteners, most preferably thermoplastic rivet fasteners. 
     As shown in FIGS. 1 and 2, the front portion of the neck band  12  includes a pair of laterally extending substantially flat side or wing portions  30 . A large tracheal opening  34  is preferably medially located in the front section of the neck band between the side wing portions  30 . Reinforcement ribs  32  or stiffening elements are formed on the neck band  12  to reinforce the body of the neck band and prevent it from tending to collapse. A spinal access opening  36  is formed in the back portion of the neck band  12 . Relief slots or serrations  38  formed in the upper lower edges of the back portion of the neck band  12  allow the neck band to flex to the contour of the patient&#39;s neck. 
     As best seen in FIGS. 1 and 3, the mandible support  14  includes a central chin support or cup  40  for supporting the wearer&#39;s chin. Extending laterally from either side the chin cup  40  is pair of laterally wings or side portions  42 . The substantially planar side portions  42  of the mandible support  14  and the substantially planar side portions  30  of the neck band  12  are slidingly engaged with each other, permitting vertical height adjustment of the collar, as described in greater detail below. 
     The specifics of the cervical collar, in particular the specifics of the chin cup, are described in greater detail in U.S. Pat No. 5,622,529, which issued on Apr. 22, 1977, entitled “Flat Cervical Collar Having a Unitary Chin Support, ” which is incorporated herein by reference. 
     As best seen in FIG. 2, a plurality of male protruding sliders  50  extend from the back surface of the neck band  12 . The male sliders  50  engage with corresponding parallel slots  52  formed in the wing portion  42  of the mandible support  14 . The slider slots  52  may be stiffened with ribs  54  on their lateral edges. The slots  52  are sized and configured to cooperate with the male sliders  50  which protrude from the back portion of the neck band  12 , so as to permit only vertical transitory movement between the mandible support  14  and the neck band  12 . The relative position of the back side of the neck band and the mandible support, is fixed a locking means  60 , which will be described in greater detail below. 
     Referring now to FIGS. 1,  5  and  6  the locking means  60  is shown. The locking means  60  includes a series of vertically aligned rectangular blocks  62  which extend from the front face of the neck band  12 . A column of these protruding blocks  62  are formed on either side of the tracheal opening  34 . Each column of blocks  62  is bounded on it&#39;s upper and lower end by an additional half-height end protrusions  64 . In this way, a slot  66  is formed between each of the blocking member  62  and between one of the end blocks  62  and the end protrusion  64 . 
     The locking means  60  also includes an extended slot  68  which is adjacent to each column of protruding blocks  62 . 
     Referring now to FIG. 3, the front surface of the mandible support  14  is shown. A pair of openings  80   a  and  80   b  are formed in the lower portion of the mandible support  14  on each side of the tracheal opening  34 . Openings  80   a  may include a peripheral rib  82 . Openings  80   b  are formed in an tab portion  84  which extends from the sidewall which forms the tracheal opening  34  of the mandible support. When the mandible support  14  is attached to the neck band  12 , the opening  80   a  is aligned with the elongated slot  68 , whereas the opening  80   b  on tab  82  extends past the edge  86  (best seen in FIG. 5) of the neck band  12  and is visible through the tracheal opening  34 . 
     Referring now to FIG. 1, the locking means  60  also comprises a U shaped clip  70 . The clip  70  is best seen in FIGS. 7-9 and includes an enlarged actuator head  72 . A pair of legs  84  extend from the bottom surface of the head  72 . The legs  74  are spaced such that the distance between the legs  74  is greater than the width of the blocks  62  which protrude from the front surface of the neck band  12 . The distance between the inner surfaces  75  of the legs  74  allows the legs  74  to engage with the openings  80   a  and  80   b  formed in the mandible support  14 . Wedge shaped locking members  76  are formed at the distal ends of the legs  74 . The locking members  76  deflect inwardly when the legs  74  to engage the openings  80   a  and  80   b . Once the locking members  76  clear the depth of the openings  80   a  and  80   b , they will return to their normal configuration and are locked within the openings  80   a  and  80   b  and cannot be removed. A protrusion or detent  78  is formed intermediately around each leg  74 . The detent  78  also engages with the openings  80   a  and  80   b  and allows the clip  70  to be removably engaged therewith. 
     The enlarged actuator head  72  may be manually manipulated by the wearer or applicator of the cervical collar to engage and disengage the legs  74  and detent  78  with the openings  80   a  and  82  of the mandible support  14 . One side of the actuator head  72  has a triangular head such that the actuator simulates an arrow. 
     In use, the clip  70  is inserted into the front surface of the neck band  12  to engage the openings  80   a  and  80   b . One of the legs  74  of the clip  70  extends through the elongated slot  68  of the neck band  12  to engage opening  80   a , the other leg  74  of the clip  70  clears the inner edge  86  of the neck band  12  and engages with opening  80   b . In this way, the clip  70  bridges the column  66  blocks  62 . The distal locking members  76  retain the clip  70  within the openings  80   a  and  80   b . The height of the actuator head  72  above the distal locking members  78  is sufficient that the bottom surface  77  of the actuator head will clear the protruding depth of the blocks  62 . 
     When the mandible support  14  is vertically displaced by a user, the extending legs  74  of the clip  70  will ride within the elongated slot  68  and in the tracheal opening  70  near the edge  86 . The rib  82  also rides within the slot  68 . When a desired height is selected by a user, corresponding to the alignment of the actuator head  72  of the clip  70  with one of the slots  66  formed between the blocks  62 , the clip  70  is depressed by the user so that the actuator head  72  engages one of the slots  66 . When the clip  70  is depressed in this lower engaged position, the actuator head  72  will prevent vertical movement of the mandible support relative to the neck band  12 . In this engaged position, the detents  78  will be engaged with the openings  80   a  and  80   b  to secure the actuator head in the engaged position. If subsequent adjustment is desired, the clip  70  can be removed by pulling the actuator head  72  away from the neck band  12 , disengaging the protrusion detent  78  from the opening  80   a  and  80   b . The clip  80  would still be retained within the openings  80   a  and  80   b  by virtue of the locking member  78 , but the lowermost surface  77  of the actuator head  72  would now be in upper unengaged position and would clear the top of the blocks  62 . 
     As best seen in FIGS. 1 and 5, indicia  99  may also be provided adjacent to each of the slots  68  to indicate a size of the cervical collar in each of the multiple positions obtainable by the collar. The triangular surface or arrow shaped head of the actuator  72  would point to one of the indicia markings. 
     An alternate version of the preferred invention is showed in the FIGS. 10-16. In FIG. 10, there is showing a multiple size cervical collar  110  which is similar to collar  10  with the exception of those features described below. 
     The collar  110  comprises a neckband  112 , and mandible support  114 , foam padding  116 , and a fastener  118 . The collar  114  has an asymmetrical shape in that the back portion  119  is not the same shape of the front portion  121  of the collar. 
     As best seen in FIG. 11, a plurality of male sliders  150  extend from the back surface of the neckband  112 . The male slides  150  engage with corresponding parallel slots  152  formed in the laterally extending portion  142  of the mandible support  114 . The slider slots  152  may be stiffened with ribs  154  on their lateral edges. The slots  152  are sized and configured to cooperate with the male sliders  150  which protrude from the back portion of the neckband  112  so as to permit only vertical translational movement between the mandible support  114  and the neckband  112 . The relative position of the backside of the neckband  112  and the mandible support  114 , is fixed by a locking means  160  which will be described in greater detail below. 
     Referring now to FIGS. 13-15, the locking means  160  is shown. The locking means  160  includes a series of vertically aligned rectangular blocks  162  which extend from the front face of the neckband  112 . A column of these protruding blocks  162  are formed on either side of the tracheal opening  134 . Each column of blocks  162  is bounded on its upper and lower end by an additional protrusion  164 . In this way, a slot  166  is formed between each of the blocks  162  and between one of the end blocks  162  and the end protrusion  164 . 
     The mandible support  114  includes a laterally extending portion  179  which extends into the tracheal opening  134 . Attached to the extending portion  179  is a protruding tab  180  which protrudes from the front face of the mandible support  114 . An opening  182  is formed in the protruding tab  180 . 
     The locking means  160  also comprises a generally U-shaped clip  170 . The clip  170  includes an enlarged actuator head  172 . A pair of legs  184  extend from the bottom surface of the head  172 . The legs  184  are spaced apart sufficiently such that one of the legs  184  can extend through the opening  182  in the protruding tab  180 , while the other leg  184  clears both the neckband  112  and the mandible support  114  such that the bottom leg  184  extends underneath the collar. The opening  182  of the protruding tab  180  is positioned such that when the clip  170  extends through the opening  182 , the bottom side of the leg  184  will slide along the front face of the neckband  112 . The width of the top leg  184  is sized to allow the leg  184  to engage any one of the slots  166 . 
     The top leg  184  includes a protrusion  186  which cooperates with the protruding tab to prevent the clip  170  from disengaging with the protruding tab  180  once it is inserted therein. The protrusion  186  includes an angled front face  188  and a transverse back face  190 . The inclined front face  188  of the protrusion  186  functions to cooperate with the opening  182  of the protruding tab  180  when the clip  170  is initially inserted therein to allow the clip  170  to slide into the opening  182 . Once the clip  170  is inserted through the opening  182 , the transverse back face  190  prevents the clip  170  from being withdrawn and unengaged from the opening  182 . Similarly, the bottom face  192  of the actuator head  172  prevents the clip  170  from being inserted too far through the opening  182 . Thus, it should be understood that the transverse back face  190  and the bottom face  192  act as stops which limit the positioning of the clip  170 . 
     Referring now to FIG. 13, the end of the bottom leg  184  is provided with a pair of laterally extending protruding rods  194  which cooperate with a pair of tracks  196  formed on the back face of the mandible support  114 . The tracks  196  are provided with a camming surface  198  which cooperates with the protruding rods  194  to form a cam/follower arrangement. The camming surface  198  includes the first inclined portion  200 , a second inclined portion  202 , a transverse portion  204 , and a rounded groove portion  206 . 
     When the clip  170  is initially inserted into the opening  182  of the protruding tab  180 , the bottom leg  184  engages with the first inclined portion  200 . As the clip  170  is pushed through the opening  182 , the inclined front face  188  deflects the top wall of the protruding tab  180  as the clip  170  is inserted therein. While the front face  188  is slipping past the opening  182 , the rod  194  are engaging the first inclined portion  200 . 
     As soon as the protrusion  186  clears the opening  182 , the protruding rods  194  finish riding up the first inclined portion  200  and fall onto the second inclined portion  202 . At this point, the transverse portion  204  of the tracks  196  prevent the clip  170  from being disengaged with the collar. When the clip  170  is aligned with one of the slots  166 , the clip  170  can be further inserted into the opening  182 . As the clip  170  is pushed further into the opening  182 , the protruding rods  194  ride up the second inclined portion  202  until the clip  170  is fully inserted into the opening  182  and the protruding rods  194  engage the rounded groove  206 . 
     In FIGS. 13 and 14. In FIGS. 13 and 14, the clip  170  is fully inserted into the opening  182  and extends within one of the slots  166 . As the protruding rods  194  engage the second inclined portion  202 , the second inclined portion  202  serves to deflect the bottom leg  184  of the clip  170 . The resiliency of the plastic leg  170  serves to press on the tracks  196  which in turn presses the mandible support  114  against the neckband  112  against the force of the opposite top leg  184 . In this way, the legs  184  of the clip  170  cooperate with the camming track  196  to press the mandible support  114  against the neckband  112  when the clip  170  is fully engaged in the opening  182  and between one of the slots  166 . This frictional fit serves to keep the mandible support  114  fixedly engaged with the neckband  112  when the clip  170  is fully engaged. 
     The bottom leg  184  is provided with an actuator and  208  which can be used by the wearer of the collar or the applier of the collar to disengage the clip  170  from the rounded grove  206 , if the collar needs to be repositioned. In addition, the top leg  184  of the clip  170  is provided with a triangularly shaped end  210  which simulates an arrow or pointer. The pointer  210  is used with a strip of indicia  212  adjacent the protruding blocks  162  to inform the user of the proper size of the collar. 
     Also, as best seen in FIG. K, the mandible support  114  is provided with a cut-out portion  126  which cooperates with an extending portion  128  of the clip  170  to further prevent displacing the mandible support relative to the neckband  112 . In operation, the collar  110  functions as follows. The mandible support  114  is translated vertically with respect to the neckband  112  until the clip  170  is aligned with one of the slots  166 . The user may utilize the indicia  212 , as best seen in FIG. 14, to determine the proper sizing of the collar  110  as the mandible support  114  is manipulated. It should be understood that the mandible support  114  can only be manipulated or moved when the clip  170  is not engaged in the slots  166  as best seen in FIGS. 12 and 13. 
     When the user determines the proper sizing of the collar, he or she may then push the clips  170  to their engaged position by pushing on the actuator head  172  as best seen in FIGS. 14 and 15. As the user pushes the clips  170  into the slots  166 , the camming rods  194  of the bottom leg  184  coact with the camming track  196  to press the mandible support  114  and the neckband  112  together. 
     The user may continue to push the clips into the openings  182  until the protruding rods  194  engage with the rounded groove  206  and the bottom face  192  of the actuator head engages with the protruding tab  180  to prevent further movement by the clip  170 . The rounded groove  206  coacts with the protruding rod  194  to secure the clips  170  in the fully engaged position as shown in FIGS. 14 and 15. 
     In addition, the resiliency of the bottom leg  184 , as it rides up the second incline surface  202  and falls into the rounded grove  206 , produces an audible sound which indicates to the user that the clip is now fully engaged into the collar. 
     Once the clips  170  are fully engaged in the collar  110 , the top leg  184  engages the top face  163  of the block  162  as it resides in one of the slots  166  to prevent further translational movement of the mandible support  114  as the force of the user&#39;s chin and the chin cup of the mandible support presses downwardly. It should also be understood that the clip  170  would also serve to prevent upward motion of the mandible support  114  since it is trapped between two blocks  162 . 
     In addition, as best seen in FIG. 15, a small protrusion  212  which extends from the bottom leg  184  of the clip  170  engages with the inner walls of the tracks  196  to also permit translational movement of the mandible support  114 . It should also be understood that the frictional fit between the mandible support  114  and the neckband  112  caused by the coaction of the legs of the clip  184  and the camming track  196  which presses the respective parts of the collar together also serves to prevent lateral motion there between. 
     As best seen in FIG. 16, a plurality of tracks of serrated teeth  220  may be provided on the back face of the neckband  112  and the front face of the mandible support  114  to further enhance the frictional fit of the cervical collar caused by the legs of the clip  184  and the camming track  196 . These serrated teeth  220  would have a substantially triangular shape which would slide past each other when the clip  170  is not in the engaged position and would allow the mandible support  114  to slide past the neckband  112 . When the clip  170  is in the engaged position, the serrated teeth  220  are pressed against each other to enhance the frictional fit between the mandible support  114  and neckband  112 . 
     While certain prefer embodiments and various modifications thereto have been described or suggested, other changes in these preferred embodiments will occur to those ordinarily skilled in the art which do not depart from the broad inventive concepts of the present invention.