turning now to the drawings , and with reference first to fig1 indicated generally at 1 . 0 . is a cushioning patellar support device constructed in accordance with the present invention . device 1 . 0 . includes a generally butterfly - shaped inflatable / deflatable air bag 12 having opposite sides 12a , 12b which , with the bag deflated , collapse to give the bag an extremely flat cross section . bag 12 is made of any suitable material , such as rubber or latex , and is shaped , as shown in fig1 to include a pair of wings 12c , 12d which join through a reduced - dimension neck portion 12e . while the bag of device 1 . 0 . may be made in various different sizes , a typical bag sized for an adult user is illustrated here with an overall length a of about 8 - inches , an overall height b of about 4 - inches , with each wing having a length c of about 23 / 4 - inches , and with neck 12e having a length d of about 21 / 2 - inches . extending upwardly from bag 12 in the region where wing 12c joins with neck 12e is a nipple 12f formed in the bag . indentations , or dips , 12g , 12h define the outer margins of wings 12c , 12d , respectively . connecting with nipple 12f in any suitable manner , and extending upwardly therefrom , is a flexible tube , or conduit means , 14 . the end of tube 14 opposite that which fits with nipple 12f is connected through a quck - disconnect , releasably lockable coupling 15 to a suitable conventional hand pump , or inflation / deflation means , 16 . a coupling which has been found to perform extremely well is a so - called luer - lok coupling . pump 16 may be operated in the usual manner by hand manipulation to control the amount of inflation for bag 12 . as will be explained , the pump may then be disconnected in order to avoid the inconvenience of having to carry it continuously at the outer end of tube 14 . prior to such a disconnection , a suitable conventional clamp is applied to the tube , downstream from coupling 15 , to prevent bag deflation . fig2 and 3 are each on drawn roughly the same scale as fig1 and show device 1 . 0 . in an operative condition . for the purpose of explanation herein , device 1 . 0 . is shown in fig2 and 3 in use by a person who has had a below - the - knee amputation of his left leg . fig2 is a left - side ( outside ) fragmentary view showing the upper leg at 18 , the stump of the amputated lower leg at 2 . 0 . and the knee and patellar region generally at 22 . to clarify somewhat the point of view of fig3 this is taken from behind the plane , and on the right side , of fig2 and downwardly from a location above the knee . in fig2 and 3 , stump 2 . 0 . is received within the usual upwardly facing cavity of a conventional below - the - knee prosthesis shown at 24 . as can be seen , the upper rim of the prosthesis , which defines the mouth of the cavity , is formed with a front valley 24a which extends below the knee , and which joins with a pair of upwardly extending lateral hills 24b . bag 12 is placed freely within the prosthesis &# 39 ; open cavity as shown , with neck 12e extending across and generally slightly above the base of valley 24a , and with wings 12c , 12d disposed against the inside faces of hills 24b . it will be noted especially that the wings in the bag extend along the sides of the leg , but not around the back . bag 12 is reversible , in a left - to - right direction ( with respect to the way in which it is placed in the prosthesis ), and in fig2 and 3 is shown with a placement whereby nipple 12f and tube 14 extend upwardly to the left outer side of the patellar region . explaining the use and operation of device 1 . 0 ., as has been suggested above , bag 1 . 0 . is placed freely within the upper front part of the cavity in a prosthesis , with such tyically being done while the user is sitting down . free rather than permanent placement of the bag allows for ready adjustment by the user to suit his or her comfort needs , and also permits free transferability of the device for use with another prosthesis if necessary . the bag is placed in the cavity in such a manner that the upper margin of neck portion 12e , with the bag inflated , provides for positive cushioned support between the rim edge in valley 24a , and the patellar region of the leg , with the user standing . this is important to prevent abrasive and direct weight - bearing contact between the prosthesis and the patellar region . in most cases , this is best accomplished by placing the bag in such a position that the upper margin of the neck portion is disposed slightly above the rim in the prosthesis &# 39 ; front valley . this is the condition , as mentioned above , which is illustrated in fig2 and 3 . with the user still in a sitting position , the stump is inserted in the prosthesis &# 39 ; cavity , and pump 16 is operated to create a slight amount of inflation for the bag . the user then stands , and further operates pump 16 to create the desired amount of bag inflation to provide for maximum support and comfort . since , in most instances , it would be an inconvenience to leave pump 16 connected to the upper end of tube 14 , a suitable clamp is applied to the tube , downstream from coupling 15 , and the coupling is disconnected to free the pump from tube 14 . the pump may be carried independently , as in a hand bag or brief case , etc . as the user walks on the prosthesis , should any change occur requiring bag inflation or deflation , it will be obvious how this readily can be accomplished . while the situation may be different for different users , it would by typical , when a user sits and takes weight off the prosthesis , to deflate the bag somewhat so as to minimize pressure on the leg . the wings in the bag provide for good cushioned lateral support , and the dips or indentations therein clear lateral regions in the leg which are especially prone to vascular or nervous constriction under pressure . it will thus be apparent how the device of the invention offers all of the advantages ascribed to it earlier . it offers a user a high degree of flexibility in placement and adjustment , and is infinitely adjustable , in an inflation sense , to take care of different particular circumstances of fitment of a stump within a prosthesis . while a preferred embodiment of the invention has been described herein , it is appreciated that variations and modifications may be made without departing from the spirit of the invention .