Anatom3DSerratus anterior
Musculus serratus anterior · Přední pilovitý sval
Muscles
Looks like
A saw-toothed sheet of muscle wrapped around the side of the ribs under the armpit, fixed to the inner edge of the shoulder blade.
What it does
Holds the shoulder blade flat against the ribs and swings it forward and up for punching and reaching overhead.
Keeping it well
Its nerve, running down the side of the chest, can be stretched or cut in surgery or sport; the shoulder blade then sticks out like a wing when you push against a wall. Weakness after an operation or injury is worth reporting early.