Abstract: Systems and methods for effecting posture of a subject who is to be positioned on a support surface having an inclinable portion such that the subject's thorax is inclinable relative to the subject's legs, are provided. An example system includes a detachedly coupleable thoracic harness having at least an inner surface and an outer surface. The inner surface being contoured to fit over shoulders of the subject. The outer surface having a fastening surface that releasable attaches to a corresponding fastening surface disposed on the inclinable portion of the support surface.