applying the cast in the form of a blank of sheet material in a semi-rigid state so as to locate upper and lower ends of the blank of sheet material at the leg and foot of said lower extremity, respectively, constituting a first, pre-application configuration,

locating side edges of said blank for circumferential enclosure of said lower extremity,

manually urging said edges toward each other, and

enclosing therein circumferentially said lower extremity, constituting a second, post-application configuration,

whereby said second configuration defines a volume into which the lower extremity is received and an inner surface to contact substantively opposing portions of the lower extremity when received therein.