on Echocardiograms why do they put the camera on your stomach and throat at the towards the end of the test what does the stomach and?

The abdomen is just a different angle of looking at the heart.

The only thing they could look at in the neck is the blood flow in the carotid arteries, which is not part of an echocardiogram, per se, but is a good thing to look at for anybody with a history of coronary artery disease.

Below the sternum is known as the subcostal view. It views the heart behind the liver. Its a surprisingly useful view giving a good view of the entire heart. Often when the other windows on the chest yield poor images you can gain most of the diagnostic information required from this one window alone. Routinely this view is used to image and interrogate the wall in the centre of the heart and to give an estimate of right atrial pressure (using the size and motion of the inferior vena cava). Ultrasound is very angle dependent and this view is superior to the others for detecting blood flow across the centre wall as the wall is oriented almost 90 degrees across the beam.

The view on the neck is known as the suprasternal view. Its used to image the aortic arch and part of the descending thoracic aorta. In practice its most useful for detecting a coarctation of the aorta (often seen when the aortic valve has two cusps not three) and for grading aortic regurgitation when severe.