Surface Anatomy of the Thorax

00:01 Finally, let's wrap things up with a little bit of surface anatomy.

00:06 Let's start with looking at some dermatomes.

00:08 We can see that the dermatomes, at least from an anterior point of view, pretty much line up with all of the T1 spinal nerves.

00:16 And we can see some important landmarks here that T1 lines up roughly with the superior thoracic aperture.

00:23 T4 is relatively at the line of the nipples and T10 is at the umbilicus.

00:29 So those can serve as some nice landmarks.

00:32 When we're trying to estimate where our dermatomes are.

00:37 We can also use some surface anatomy to infer the borders of the heart.

00:41 For example, if we palpate the ribs, we can get an idea of where the heart is going to lie.

00:47 Notably, if we palpate down to the third and sixth ribs, we can find the superior and inferior borders of the heart.

00:55 And if we palpate the clavicle and find the midpoint and imagine a line going all the way down from there, we have the mid clavicular line to give us an estimate of the left border of the heart.

01:08 We can also use our knowledge of anatomy to guess the location and orientation of the aortic, pulmonary, tricuspid, and mitral valves.

01:19 Even more so we can guess because of the orientation of these, where we can best hear the aortic, pulmonary, tricuspid, and mitral valves.

01:31 So using that map, we can find for example, the second intercostal space, which we know we can use from the angle of Louis or the sternal angle, just to the right of the sternum to best listen to the aortic valve.

01:46 And we can slide over to the left side of the sternum as a place to listen to the pulmonic valve.

01:53 And from there go down to the fourth intercostal space to best hear the tricuspid and then down another to the fifth intercostal space and over to that midclavicular line to best auscultate the mitral valve.

02:08 Similarly, we can use our knowledge of the ribs and sternum to find the best intercostal spaces to auscultation the lungs both from the anterior point of view and the posterior point of view.