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Hiccups explained

What Is the Diaphragm? How It Works and How Hiccups Involve It

2 min read · Published 29 October 2026

Written from the public health sources listed below. This article has not yet been reviewed by a clinician. See our editorial policy.

The diaphragm is a dome-shaped muscle that sits between your chest and your abdomen. It is the main muscle you use to breathe.[1]

Where Is It?

It forms a sheet beneath your lungs, separating the chest cavity from the stomach area. The heart and lungs sit above it; the stomach, liver and other organs sit below.

How It Helps You Breathe

  • Breathing in: the diaphragm contracts and flattens, which enlarges the chest space and draws air into the lungs.
  • Breathing out: it relaxes and returns to its dome shape, and air flows out.

You do this about every few seconds without thinking, because the control is automatic. It is also why you can override it briefly, for example to hold your breath.

These are standard physiology basics. The diagram below shows the dome moving.

How a hiccup happens: animated diagram A simplified side view of the chest and upper abdomen. The diaphragm, a dome-shaped breathing muscle under the lungs, suddenly contracts. Air is pulled in, then the vocal cords briefly close, which makes the hic sound. Chest Lungs Windpipe Nerve signal Diaphragm Upper abdomen Vocal cords (schematic view) HIC! Slow motion That sudden contraction and vocal cord closure create the familiar hic sound. DrHiccups Understand Hiccups. Find Relief. Know When to Get Help. drhiccups.com

Then the vocal cords briefly snap shut, cutting off the incoming air.

What Is a Diaphragm Spasm?

Hiccups are repeated spasms, or sudden involuntary movements, of the diaphragm. Each spasm pulls air in abruptly, and the vocal cords snap shut, producing the “hic” sound.[1][2] Anything that irritates the nerves serving the diaphragm can start them.[3]

Not every sensation under the ribs is a hiccup. If you have pain, breathlessness or symptoms that worry you, see a doctor rather than guessing.

Keep Reading

Coming soon

Explore the Practical Hiccups Video Guide

The animated explainer in the DrHiccups guide shows the diaphragm in action.

Educational only. The guide does not replace medical advice or treatment.

See the Guide DetailsWatch the free animation

References

  1. Hiccups. Cleveland Clinic.
  2. Hiccups. Michigan Medicine, University of Michigan Health.
  3. Hiccups. MedlinePlus Medical Encyclopedia, U.S. National Library of Medicine.

Medical disclaimer: this article is general information, not medical advice.