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Recovery Tip

Did you know that your core muscles, which are the deepest layer of your tummy muscles, should work at all times to brace and protect your back? These muscles switch off due to pain and it takes 50,000 repetitions before they work automatically again to protect your back!

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MUSCLE OF THE MONTH - Serratus Anterior

Serratus anterior (sir-ah-tus an-teer-e-er)


Where is it

You’ll find your serratus anterior underneath a few layers of superficial muscles, under the arm. You can see it peeking out in this picture here.




The serratus anterior is made up of nine or ten finger-like slips of muscle that begin on the first eight to nine ribs. There are usually nine to ten slips though, and it is common for there to be two slips arising from the second rib. Variations occur naturally throughout the human species.



The slips travel up and around the rib cage to finish on the underside of the inner edge of the shoulder blade. 



Action & Function

Serratus anterior is a crucial muscle in shoulder function. When the serratus contracts, the shoulder blades are pulled forward around the rib cage. This movement is called protraction. Because of the angle of the pull, the shoulder blade is also upwardly rotated a little bit.

When the serratus anterior is switched on in conjunction with it’s antagonist (opposite function muscle) the rhomboids, they work against each other and end up stabilising the shoulder blade. This is probably serratus’ most important function. It means that the shoulder blade is a stable base for the arm to move from allowing for more powerful movement.



This muscle is supplied by the long thoracic nerve, which travels around the ribcage along the length of the muscle.

The arteries that supply blood to the serratus anterior are the lateral thoracic artery for the upper section of the muscle and the thoracodorsal artery for the lower section.


Fun Fact

Serratus anterior is often referred to as the ‘Boxer’s Muscle’. This is because athletes who box often spend a lot of time with their shoulder blades forward around their ribcage (scapular protraction) when in a defensive position.

In addition, boxers tend to have very low body fat percentage meaning the serratus is quite visible when the arm is extended e.g. during a swing at another opponent