Muscle
Diaphragm
Principal muscle of respiration
High-yield
Phrenic nerve (C3, C4, C5 keeps the diaphragm alive). Descends on contraction to enlarge the thorax. Caval (T8), esophageal (T10), aortic (T12) hiatuses.
Overview
The dome-shaped musculotendinous partition between the thorax and abdomen that is the primary muscle of inspiration.
Reference facts
- Origin
- Xiphoid process, lower six costal cartilages, and lumbar vertebrae (crura at L1-L3)
- Insertion
- Central tendon of the diaphragm
- Action
- Contracts and descends to increase thoracic volume - primary muscle of inspiration; increases intra-abdominal pressure
- Innervation
- Phrenic nerve (C3, C4, C5)
- Blood supply
- Inferior phrenic, musculophrenic, and pericardiacophrenic arteries
Frequently asked questions
What does the diaphragm do?
The diaphragm contracts and descends to increase thoracic volume - primary muscle of inspiration; increases intra-abdominal pressure.
What nerve innervates the diaphragm?
The diaphragm is innervated by the phrenic nerve (C3, C4, C5).
Where does the diaphragm attach?
The diaphragm originates from the xiphoid process, lower six costal cartilages, and lumbar vertebrae (crura at L1-L3) and inserts on the central tendon of the diaphragm.
What is the blood supply of the diaphragm?
The diaphragm is supplied by the inferior phrenic, musculophrenic, and pericardiacophrenic arteries.