Diaphragm
Diaphragma
The diaphragm is the dome-shaped sheet of muscle separating the thorax from the abdomen and is the primary muscle of breathing. Beyond respiration, it forms the roof of the deep-core canister and, by descending against a braced abdominal wall, generates the intra-abdominal pressure that stabilizes the spine. Diaphragmatic (belly) breathing and coordinated bracing with the Valsalva maneuver are foundational to safe heavy lifting.
- Actions
- Primary muscle of inspiration, Increases intra-abdominal pressure, Contributes to spinal stability via pressure, Aids in the Valsalva maneuver
- Origin
- Xiphoid process, internal surfaces of lower six costal cartilages and ribs, arcuate ligaments, and bodies of upper lumbar vertebrae (via the crura)
- Insertion
- Central tendon of the diaphragm
- Innervation
- Phrenic nerve (C3-C5)
- Blood supply
- Inferior phrenic, superior phrenic, pericardiacophrenic, musculophrenic, and lower posterior intercostal arteries
Synergists Transversus Abdominis
Tendons Central Tendon of the Diaphragm