A chair assembly includes a four-bar linkage assembly including a first linkage member, a second linkage member, a third linkage member and a fourth linkage member each pivotably coupled to one another such that the four-bar linkage assembly includes an upper end that is adjustable between raised and lowered positions, and an arm rest assembly adapted to support the arm of a seated user thereon and supported the upper end of the four-bar linkage assembly, wherein a lower end of the four-bar linkage assembly is pivotably supported from an arm support structure for pivotable movement, such that the upper end of the four-bar linkage assembly is moveable between a first position and second position located laterally outward from the first position.