A head restraint assembly is provided and includes a base including a cross member. Also included is a head restraint having a housing. Further included is an internal cavity at least partially defined by the housing. Yet further included is a lock mechanism assembly retained within the internal cavity, the lock mechanism assembly comprising first and second lock members, the first lock member including a first plurality of teeth and the second lock member including a second plurality of teeth, wherein the pluralities of teeth are engageable with each other and selectively rotatable with respect to each other in first and second directions. Also included is an actuator arm engaged with the second lock member and configured to selectively permit rotation of the second lock member relative to the first lock member.