The radial artery is a major artery in the human forearm. It is close to the surface of the underside of the forearm; when the palm of the hand is pointing upwards, so is the radial artery. The radial artery supplies the arm and hand with oxygenated blood from the lungs. Due to the size of the radial artery, and its proximity to the surface of the arm, this is the most common artery used to measure a patient's pulse. The pulse is checked at the wrist, where the radial artery is closest to the surface. The radial artery is also commonly used when drawing arterial blood for ‘Arterial Blood Gas’ (ABG) measurement. This is done for three reasons: firstly, it is not the only supplier of blood to the arm. If the radial artery is damaged, the ulnar artery will take over. Secondly, it is easy to access. Thirdly, the radial artery is a superficial artery; this means that damage is easily repaired and rarely endangers the patient.