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