Breathe in. In that one simple motion, your diaphragm tightened up and moved down. This made your chest cavity bigger. Your intercostal muscles between your ribs tightened up, too. This made your rib cage move up and out.
Now breathe out. Your diaphragm loosened up and moved back up into your chest cavity. Your intercostal muscles relaxed as well, making your chest cavity smaller.
Sometimes it's not this simple. When you have trouble breathing, also called respiratory distress, your muscles can't do their job. They're still trying to get air into your lungs, but the lack of air pressure causes the skin and soft tissue in your chest wall to sink in. This is called a chest retraction.
It’s easy to spot in babies and small children because their chests are softer and haven't fully grown yet. Usually, they’re caused by:
- Croup, swelling in a baby’s upper airways
- Respiratory distress syndrome, breathing trouble in newborns
- Bronchiolitis, or swelling in the smallest airways of the lungs
- Buildup of infected pus in the back of the throat
Chest retractions can happen at any age if something's blocking your windpipe. In adults, they're also caused by:
- A bad allergic reaction
- Epiglottitis, when the tissue that covers your windpipe swells up
The kind of chest retractions you have depends on their location.
Subcostal retractions: When your belly pulls in beneath your rib cage
Substernal retractions: If your belly pulls beneath your breastbone
Suprasternal retractions: When the skin in the middle of your neck sucks in. It’s also called a tracheal tug.
Superclavical retractions: Happen on the part of your neck above your collarbone
Intercostal retractions: Happen between each rib
Wherever they're happening, chest retractions mean your body's not getting enough air. If you're having them, or you're with someone who is, get help fast.