with reference to fig1 and 2 , a support surface or pad 10 suitable for use with a stretcher is constructed of a plurality of foam layers . a base layer 12 is preferably formed of hr ( high resiliency ) foam ( e . g ., 1 ″ thick ) for substantial deep support . an open cell foam middle layer 14 is supported on the base layer 12 , and a top layer 15 preferably formed of a visco - elastic foam material ( so called “ memory foam ”) may be disposed over the middle layer 14 . the middle layer 14 includes a plurality of foam pads that define independent support zones of varying densities . as shown , the plurality of pads define a head section 16 , a body section 18 , and a foot section 20 separated by a plurality of lateral channels 22 . in a preferred arrangement , the lateral channels 22 extend through the respective sections or “ foam support zones ” 16 , 18 , 20 to the base layer 12 . the foam support zones 16 , 18 , 20 may additionally include a longitudinal channel 24 dividing the head 16 , body 18 , and foot 20 sections into left and right side head , body and foot sections as shown . the longitudinal channel preferably also extends through the support zones 16 , 18 , 20 to the base layer 12 . in a preferred construction , densities of the foam support zones vary by section 16 , 18 , 20 . that is , the density of the head section 16 is preferably lower than the density of the body section 18 , and the density of the foot section 20 is also preferably lower than the density of the body section 18 . moreover , the density of the foot section 20 is preferably lower than the density of the head section 16 . the head 16 and foot 20 sections are generally softer than the body section 18 since the head and heels exert a higher pressure on the support surface 10 . with continued reference to fig1 , the body section 18 includes an upper body section 18 a , a middle body section 18 b and a lower body section 18 c . densities of the foam support zones in the upper 18 a , middle 18 b and lower 18 c body section preferably also vary by section . the variances in the zones / sections of the stretcher have been specified in an attempt to manage the anatomic characteristics of the average human body . an example would be that generally the sacral and scapulae carry the bulk of the weight in a back lie orientation . these areas therefore require a stackup that reacts ( supports the body ) quicker than the upper thigh for instances which can be allowed to sink deeper before the real support layers begin to hold the body more substantially . as shown , the head section 16 is formed of a foam block 26 having a lateral slot 28 parallel to the lateral channels 22 . the lateral slot 28 in the foam block 26 of the head section 16 preferably extends about halfway into the foam block 26 . the foam block 26 is preferably formed of a soft foam treated with tighter shallower cuts to create initial very soft immersion . that is , when cuts are made into the top of a foam block , the surface between the cuts collapse easier than the same type of foam without the cuts . additionally , the amount of space between the cuts contributes to the overall softness / firmness of that particular area . deeper closer cuts are softer than shallow widely spaced cuts . the body section 18 includes a plurality of foam blocks 30 ( six shown in fig1 and 2 , preferably about 3 ″ thick progressively supportive foam pads ) separated by body lateral channels 22 ′ parallel to the lateral channels 22 separating the head section 16 , the body section 18 and the foot section 20 . the foot section 20 is constructed of a foam block 32 having at least one lateral slot 34 therein parallel to the lateral channels 22 . as shown in fig1 and 2 , the foam block 32 of the foot section 20 is provided with two lateral slots 34 . the lateral slots 34 are shown in a keyhole shape to facilitate a downward orientation of the foot section 20 relative to the body section 18 . that is , the foot section 20 preferably slopes downward in an arc from the body section 18 . the downward slope serves to shift heel pressure toward the patient &# 39 ; s calves , resulting in increased comfort . additionally , the lateral slots 34 serve to better distribute pressure in the patient foot area . the foot section 20 foam allows excellent immersion . the assembly may additionally include a top cover formed of a suitable material such as 4 - way stretch polycarbonate and a bottom cover formed of a suitable material such as non - slip vinyl ( not shown ) surrounding the support surface . in use , the lateral channels 22 , 22 ′ and lateral slots 28 , 34 along with the longitudinal channel 24 serve to break tension through the supportive layers and create independent / separate progressively supportive pressure displacement areas across the entire length and width of the support surface 10 . the foam support zones address load requirements ( firmness and support characteristics ) to localized areas of the pad 10 . the top layer 15 provides an excellent interface and relaxed continuity to the underlying support pads . the base layer 12 provides a firm foundation of support and continuity to the pad . the channels and slots additionally provide for better air circulation within the pad , resulting in a cooler and more comfortable surface . while the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments , it is to be understood that the invention is not to be limited to the disclosed embodiments , but on the contrary , is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims .
a support surface suitable for use with a stretcher includes multiple foam pads of independent zonal pressure support such that a transfer of force by pressure on one foam pad to an adjacent foam pad is limited .