To analyze the venous wave form, one must first, of course, look in the anatomic area where it is best seen, and that is on the inferolateral aspect of the sternocleidomastoid muscle, and then one must have a timing mechanism, and the carotid is an excellent timing mechanism as are the heart sounds. In this case, let us use the carotid vessel to time those venous impulses and, when you do, you clearly see - especially looking tangentially here - the "a" wave and the "v" wave of the venous pulse. It's so clear that the "a" wave occurs just before, and the "v" wave just after, the carotid impulse.