A diaphragm is a thin muscle under your lungs that separates your chest from your abdomen, and its main job is to help you breathe. When it contracts, it flattens and helps draw air into the lungs; when it relaxes, air moves back out.

What it does

  • Helps you inhale and exhale.
  • Supports coughing, sneezing, vomiting, urination, and bowel movements by increasing pressure in the abdomen.
  • Helps reduce acid reflux by putting pressure near the esophagus.

Simple picture

Think of it like a flexible sheet at the bottom of your chest: it moves down to pull air in, then moves back up to push air out. That movement happens automatically most of the time, even though you can also control it a bit during deep breathing.

In everyday terms

If someone says “diaphragm,” they usually mean the breathing muscle in your body. It’s essential for normal respiration, so problems with it can make breathing harder.