An arm support board for supporting the arm and wrist of a medical patient with the wrist advantageously exposed for an invasive medical procedure. The arm support board may comprise a base which is generally triangular in side view, a discardable liner which mounts to the upper surface of the base to engage the arm of the patient, and discardable straps for affixing the arm of the patient to the arm support board. The straps may be passed through slots which pass through the liner. The arm support board may comprise a supplemental two part articulated support board which follows the configuration of the arm of the patient. The base may incorporate a track for slidably receiving the supplemental support board.
