An adjustable support apparatus used to support a person in a specific position over an extended period of time, and method of using the same. The apparatus has a base, an adjustable plate clamp assembly with upper and lower plates, a pivot within the apertures of the plates and adjustably retained between the plates, and a support member attached to the pivot and adapted to support a load. The adjustable plate clamp assembly has upper and lower plates. The upper plate has a central upper aperture, a first end pivotally attached to the base, and a second end. The lower plate has a central lower aperture, a first end, and a second end pivotally attached to the second end of the upper plate. The first end of the lower plate bears against the base, the plates together form an acute angle, and the apertures are aligned with one another.