A patient support apparatus having a support structure with a primary support surface for a patient, and an extension manually movable by a user relative to the support structure from a stowed position to an extended position so that the extension provides auxiliary support for the patient in the extended position. A locking device is operable to releasably hold the extension relative to the support structure in the stowed position and the extended position. A release mechanism is operable to manipulate the locking device to release the extension for movement relative to the support structure, and is movable with the extension from the stowed position to the extended position.