Yoga Glossary · Muscles
Diaphragm
The dome-shaped main muscle of breathing, sitting under the ribs.
The diaphragm is a broad dome of muscle separating the chest from the abdomen. When it contracts, it flattens downward, drawing air into the lungs and gently massaging the abdominal organs; when it relaxes, it domes back up and air leaves. Most of the air you move in quiet breathing is the diaphragm's work, not the chest's.
Yoga's breath practices are diaphragm training. Slow diaphragmatic breathing — belly and lower ribs expanding on the inhale — is the base under Ujjayi and three-part breath, and it is linked to the calming side of the nervous system. In poses, the diaphragm also teams with the pelvic floor and deep core to manage pressure in twists, folds and arm balances.
In practice
- If only your chest rises when you inhale, the diaphragm is underused — aim the breath at the belly and back ribs.
- A sighing exhale is the diaphragm fully relaxing; long exhales are a nervous-system cue, not just air leaving.
- Tight folds compress the belly and limit its travel — come up a little to breathe fully.
Poses that engage it
Related terms
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The Yoga Glossary is an educational study reference. Definitions are standard yoga and anatomy knowledge in plain language; nothing here is medical advice.