Final answer:
The radiation of a murmur best heard at the aortic valve is typically associated with the right sternal border, due to the anatomical position of the heart's aortic valve and the initial portion of the aorta within the thoracic cavity.
Step-by-step explanation:
The anatomical location typically associated with the radiation of a murmur best heard at the aortic valve is the right sternal border. The aortic valve's sounds are best auscultated at the second intercostal space at the right sternal border. This is due to the position of the heart within the thoracic cavity, where the initial portion of the aorta rises superiorly from the left ventricle, directing the sound towards this area.
A murmur is a sound due to turbulent blood flow within the heart, and auscultation is the method by which these sounds are heard using a stethoscope. Proper placement of the bell of the stethoscope is crucial for accurate auscultation of the different heart valves.