Which muscles are used when inspiration is forced?

- Diaphragm: Contracts and moves downward, expanding the thoracic cavity.

- External intercostal muscles: Contract to elevate the ribs and sternum, further expanding the thoracic cavity.

- Scalene muscles: Help elevate the first two ribs and sternum.

- Sternocleidomastoid muscles: Assist with elevating the sternum.

- Pectoralis minor muscles: Help elevate the third to fifth ribs.

- Serratus anterior muscles: Pull the ribs upward and outward, expanding the thoracic cavity.