Muscles of respiration

Muscles of respiration are those muscles of the body, which help lungs in the process of exchange of gases.

Diaphragm:

It is the primary muscle of respiration. For more details, click here

Levatores costarum muscle:

These are 12 pairs of muscles each arising from the tip of the transverse process of a thoracic vertebra and inserted into the rib below. Each muscle is triangular in shape with its apex lying towards the origin.

Action: Each muscle raises the rib below and is therefore and inspiratroy muscle.

Nerve supply: Each muscle is supplied by posterior ramus of corresponding thoracic spinal nerve.

Serratus posterior superior muscle:

It is a thin flat muscle that arises from the lower cervical and upper thoracic spines. Its fibers pass downward and laterally to be inserted into the upper ribs.

Action: Serratus posterior superior muscle elevates the ribs on its contraction and is therefore a inspiratory muscle.

Nerve supply: It is innervated by the intercostal nerves.

Serratus posterior inferior muscle:

It is also a flat muscle that arises from the lower thoracic and upper lumbar spines. It passes upward and laterally to be inserted into lower ribs.

Action: On its contraction, it depresses the ribs and is therefore an exspiratory muscle.

Nerve supply: It is also innervated by intercostal nerves.