Abstract: An apparatus for supporting a patient's hand, wrist, and at least a portion of the forearm in order to expose the radial artery to receive an arterial line. The apparatus including a substantially flexible, unitary body adapted to underlie the posterior of the patient's hand, wrist and forearm. The unitary body including a forward portion having an upturned cutout portion for receiving finger portions of a patient's hand. The forward portion configured for mating engagement with the posterior surface of the hand. The unitary body further including a rear portion sloping downward from the forward portion and having an upturned cutout portion for receiving a forearm portion of a patient.