addition integrally formed and proximally projecting top guide 118 and middle guide 120 bracketing each vertical end of the cutting edge 116 further define a tissue staging area 122 assisting in guiding tissue to the sharp cutting edge 116 prior to being severed the middle guide 120 also serves to engage and fire the staple applying apparatus 12 by abutting a stepped central member 124 of a wedge sled 126 fig5 that effects staple formation by the staple applying assembly 12 as described in greater detail below forming these features e g top pins 110 middle pins 112 and bottom foot 114 integrally with the e beam 102 facilitates manufacturing at tighter tolerances relative to one another as compared to being assembled from a plurality of parts ensuring desired operation during firing and or effective interaction with various lockout features of the staple applying assembly 12 in fig6 7 the surgical stapling instrument 10 is shown open with the e beam 102 fully retracted during assembly the lower foot 114 of the e beam 102 is dropped through a widened hole 130 in the staple channel 18 and the e beam 102 is then advanced such that the e beam 102 slides distally along a lower track 132 formed in the staple channel 18 in particular the lower track 132 includes a narrow slot 133 that opens up as a widened slot 134 on an undersurface of the staple channel 18 to form an inverted t shape in lateral cross section as.