A support assembly attachable to a patient support is disclosed. The support assembly includes a support unit configured to support one or more devices, and two connector units removably attachable to the patient support. The support unit includes a shelf for supporting one or more devices, two support legs extending downwardly from the support shelf and spaced apart from each other, and two support feet. The two connector units each include a patient support attachment portion removably attachable to the patient support, and a support unit attachment portion removably attachable to the respective support unit. The support unit attachment portion and the respective support foot include inter-engageable elements which can be moved relative to one another to move the support unit between an extended position and a retracted position when the two connector units are attached to the support unit. A patient support assembly is also disclosed.