hi everybody dr. Mike here in this video we're going to look at surface anatomy relating to the heart and also heart sounds that lub-dub lub-dub that we often refer to so first thing is we know that our hearts it's within our chest specifically an area termed the mediastinal and it sits behind our ribcage behind our sternum and we have our lungs either side now if you take your fist place it at your sternum then shift it a little bit towards the left and then tilt your fist so that you can draw a straight line down your knuckles to your left hip that's approximately the size and placement of your heart within your chest now what you can see is the top of the heart what we term the base funnily enough that sits at around about the second rib and the apex or the pointy bottom that's pointing towards your left hip that sits at around about the fifth intercostal space now if you want to find this fifth intercostal space what you can do is go midclavicular get your left clavicle go midline down midline across move down towards your nipple and as you get to your nipple midclavicular feel the first intercostal space this is the first space between your ribs just below your nipple this is approximately the fifth intercostal space and if we're to just pause and feel that you should be able to feel your heart at that fifth intercostal space that's because the apex of your heart is beating against your chest wall so the base sits at the second rib approximately and the apex sits at the fifth intercostal space all right now what I've drawn up here is that heart sitting within the ribcage now what I've actually done is move the heart to sit more superficially so it sits outside the ribcage but we know that the heart sits within and the sternum is protecting predominately the heart and you've got the ribs as well here's the clavicle or clavicles I should say a couple of things I want to refer back to the valves of the heart remember that you have two atria of the heart at the top two ventricles down the bottom blood always enters the atria and then the atria contract push blood down into the ventricles the ventricles contract push blood out of the heart now in order for blood to move from the atria to the ventricles they need to move through valves either side the right-hand side from the atria to the ventricles have valves the left hand side has HRM ventricles okay and valves in between if we look at the right hand side going from right atrium to the right ventricle The Velvet moves through something called a tricuspid valve now the tricuspid valve is this valve right here and like I said you're moving blood from the right atrium to the right ventricle through the tricuspid valve this is deoxygenated blood now on the left hand side we've got blood moving from the left atrium to the left ventricle through another valve called the bicuspid valve also known as the mitral valve and this is the Marshall valve here left ventricle left atrium through the valve left ventricle all right so these are those two valves that we term the Atrio ventricular valves because they sit between the atrium and the ventricles now we need to talk about another set of Valve's called the semilunar valves now when those ventricles contract when the right ventricle contracts it pushes blood out of the heart to the lungs via the pulmonary artery and the pulmonary artery more specifically the trunk has a valve there called the semilunar valve it's called the pulmonary semilunar valve okay now the pulmonary semilunar valve you can see is sitting right here so when that right ventricle contracts it pushes blood up to go to these pulmonary arteries through the pulmonary valve all right pulmonary semilunar valve now on the left hand side when blood goes from the left ventricle out through the aorta it needs to go through a valve semilunar valve the aortic semilunar valve and that's this one right here okay why am I telling you about these valves it's because you can see say where they sit predominately and they sit predominately behind the sternum okay now this is important clinically because sometimes we need to listen to heart sounds why because there's two predominant heart sounds that lub-dub lub-dub lub-dub to the lub is termed the first heart sound and what happens is this as blood goes from the atria to the ventricles blood moves through the atrioventricular valves then the ventricles contract right and those valves are closed and blood turbulent blood dynamic blood moving blood hits those closed doors the closed H over and tricular valve doors which means the first heart sound is due to closure of the H R ventricular valves so when you listen to the first heart sound auscultation is the term that we use for listening so when you listen to these heart sounds and you listen to s1 you listening to whether there's any murmurs associated with closure of the AV valves perfect the second heart sound the dub is when the blood moves from the ventricles out of the respective arteries whether it's the pulmonary arteries or whether it's the aorta has to go through the pulmonary semilunar valve and the aortic semilunar valve and as it moves through they then close and as the blood wants to come back in the blood hits the wall turbulent blood hits the closed doors therefore the second heart sound that dub is due to closure of the semilunar valves all right and again auscultation of these valves can tell you whether there's a problem or a murmur a murmur is simply disrupted turbulence of blood through the heart now because they sit behind the sternum it's difficult to listen to it because it's muffling that sound it's blocking it but there's other parts of the heart we can listen to to hear those valves this is what this part of the lecture is about so if you want to listen to the mitral valve that's the valve that separates the left atrium from the left ventricle instead of going here behind the sternum you can go to the apex of the heart and I told you the apex of the heart sits at the fifth intercostal space on the left hand side right there perfect if you want to listen to the tricuspid valve you can stay at that fifth intercostal space move more medially towards the middle and you'll be able to hear the tricuspid valve what about the semilunar valves well the base of the heart sits at the second rib if you go to the second intercostal space on the left hand side you should be able to hear the pulmonary on the right hand side you should be able to hear the aortic so this is surface anatomy relating to the heart and this is the heart sounds as well