A surgical apparatus (10) comprises a handle assembly (12), an elongated body (14, 16, 200) extending distally from the handle assembly and defining a longitudinal axis and a tool assembly (17) supported at the distal end of the elongated body. The tool assembly is pivotable about a pivot axis (244) with respect to the elongated body and includes an anvil assembly (20) and a cartridge assembly (18) having a plurality of surgical staples. A drive assembly (212, 266) has a drive member (212)extending from a position proximal of the pivot axis (244) to a position distal of the pivot axis (244). The drive member has a distal end (268, 286,)which is movable in relation to the tool assembly to actuate the tool assembly. A blow out member (254) positioned on one side of the drive member extends from a position proximal of the pivot axis to a position distal of the pivot axis, to inhibit outward bulging of the drive member.
