Radiation refers to spread of a murmur from its point of maximum intensity. In general, sound is projected in the direction of blood flow. The murmur of aortic stenosis, generated distal to the aortic valve, radiates up to the ascending aorta, explaining why it is loudest at the second right intercostal space, and continues into the neck. The murmur of pulmonic stenosis, on the other hand, radiates from the second left intercostal space via the pulmonary arteries to the lung fields bilaterally, especially on the left.