The diaphragm
Diaphragm · diaphragma
The dome-shaped muscle under your lungs that does most of the work of breathing.
What it does
The diaphragm is a sheet of muscle that separates the chest from the abdomen. When it contracts, its dome flattens and pulls down, making room for the lungs to fill. When it relaxes, it rises and air flows out. The oesophagus, aorta and a large vein pass through openings in it.
Surprising fact
Hiccups are sudden involuntary spasms of the diaphragm, followed by the snap shut of the vocal cords that makes the "hic".
Why it matters
Breathing slowly from the belly lets the diaphragm do most of the work, which can calm a racing heart. The nerve that drives it comes from the neck, so neck injuries can affect breathing.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.