An adapter assembly for operably connecting an end effector to a surgicalinstrument.The adapter assembly includes a first proximal shaft, a second proximal shaft,a first distalshaft, and a second distal shaft. The first proximal shaft includes a firstgear assembly. Thesecond proximal shaft defines a longitudinal axis and includes a second gearassembly. Thefirst distal shaft is disposed along the longitudinal axis and includes athird gear assembly.The first gear assembly is mechanically engaged with the third gear assembly.The seconddistal shaft includes a fourth gear assembly. The second gear assembly ismechanicallyengaged with the fourth gear assembly. A distal portion of the second distalshaft is disposedat least partially within an internal cavity of the third gear assembly.
