BRINGING ANATOMY TO LIFE

In each issue we will feature an article which is aimed at bringing different muscles to life. In this issue we have started with the two main breathing muscles - the diaphragm and the intercostals - as these are notoriously difficult to visualise as well as explain to clients.

THE DIAPHRAGM

The breathing action online

Click on the images below to show how the diaphragm and the intercostal muscles work during the breathing cycle and the effect they have on the lungs.

The diaphragm muscle - as the diaphragm muscle contracts, its muscle fibres shorten causing the dome shape to flatten. As the diaphragm is connected to the lungs, this draws the lungs downward, increasing the height and capacity of the lungs and thereby lowering the lung pressure, causing air to be sucked in from the external environment.

THE INTERCOSTAL MUSCLES

With thanks to Primal Pictures and YMCAfit for the use of the animations on these pages.

The intercostal muscles - as the intercostals contract, they cause a tilt in the ribs, a little bit like the movement of a bucket handle. This in turn results in a small but significant change by drawing the lungs out to the side - increasing the width of the lungs laterally - and because of the way the ribs are shaped, also pushing the sternum forward a small distance - increasing the depth of the lungs antero- posteriorly. Again this increases the lung capacity and results in air being sucked in from the external environment.

20

The REPs Journal 2009;14(Sept):20-21