What are the inspiratory muscles?

1. Diaphragm:

- The principal muscle of inspiration.

- Innervated by the phrenic nerves (C3-C5).

- Contracts and flattens, enlarging the thoracic cavity in the vertical dimension.

2. External intercostal muscles:

- Located between the ribs.

- Innervated by the intercostal nerves (T1-T11).

- Contract to pull the ribs upward and outward, increasing the thoracic volume.

3. Accessory muscles of inspiration:

- Used when increased respiratory effort is needed, such as during exercise or respiratory distress.

- Include the sternocleidomastoid, scalenes, and pectoralis minor muscles.