A surgical instrument , comprising: an elongate shaft defining a shaft axis, a surgical end effector coupled to said elongate shaft for selective articulation relative to said elongate shaft about an articulation axis that is transverse to said shaft axis; at least one articulation link (1710L; 1710R) operably interfacing with a source of articulation motions and being coupled to said surgical end effector for applying said articulation motions thereto; an articulation lock arrangement comprising an articulation lock member (2224; 2228) corresponding to each said articulation link (1710L; 1710R), each said articulation lock member (2224; 2228) configured to laterally move into locking engagement with said corresponding articulation link (1710L; 1710R) from an unlocked position that is laterally adjacent to said corresponding articulation link (1710L; 1710R); and actuation means operably interfacing with each of said articulation lock members (2224; 2228) and configured to selectively laterally bias each said articulation lock member (2224; 2228) laterally outward, away from said shaft axis, from said unlocked position into locking engagement with said corresponding articulation link (1710L; 1710R); characterized in that each said at least one articulation link (1710L; 1710R) comprises an articulation gear rack (1720; 1723) and wherein said articulation lock member (2224; 2228) corresponding thereto comprises a locking gear rack (2226; 2230) that is oriented relative thereto in a lateral confronting relationship for meshing engagement therewith when said corresponding articulation lock member (2224; 2228) is laterally advanced toward said articulation link (1710L; 1710R). an elongate shaft defining a shaft axis, a surgical end effector coupled to said elongate shaft for selective articulation relative to said elongate shaft about an articulation axis that is transverse to said shaft axis; at least one articulation link (1710L; 1710R) operably interfacing with a source of articulation motions and being coupled to said surgical end effector for applying said articulation motions thereto; an articulation lock arrangement comprising an articulation lock member (2224; 2228) corresponding to each said articulation link (1710L; 1710R), each said articulation lock member (2224; 2228) configured to laterally move into locking engagement with said corresponding articulation link (1710L; 1710R) from an unlocked position that is laterally adjacent to said corresponding articulation link (1710L; 1710R); and actuation means operably interfacing with each of said articulation lock members (2224; 2228) and configured to selectively laterally bias each said articulation lock member (2224; 2228) laterally outward, away from said shaft axis, from said unlocked position into locking engagement with said corresponding articulation link (1710L; 1710R); characterized in that each said at least one articulation link (1710L; 1710R) comprises an articulation gear rack (1720; 1723) and wherein said articulation lock member (2224; 2228) corresponding thereto comprises a locking gear rack (2226; 2230) that is oriented relative thereto in a lateral confronting relationship for meshing engagement therewith when said corresponding articulation lock member (2224; 2228) is laterally advanced toward said articulation link (1710L; 1710R). <EOS>