Muscles of respiration

Muscles of Respiration

The Muscles of Respiration are a group of muscles that play a crucial role in the process of respiration. These muscles facilitate the expansion and contraction of the thoracic cavity, enabling the process of inhalation and exhalation.

Illustration of the human respiratory system, including the muscles of respiration.

Primary Muscles

The primary muscles involved in respiration include the diaphragm and the intercostal muscles.

Diaphragm

The diaphragm is a dome-shaped muscle located at the base of the lungs and thoracic cavity. It is the primary muscle used in respiration, responsible for about 75% of the air movement in normal breathing at rest.

The diaphragm in a relaxed and contracted state.

Intercostal Muscles

The intercostal muscles are several groups of muscles that run between the ribs, and help form and move the chest wall. These muscles are involved in the mechanical aspect of breathing.

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The intercostal muscles.

Accessory Muscles

The accessory muscles of respiration, used primarily during vigorous exercise or acute conditions, include the sternocleidomastoid, scalene, and pectoralis major muscles.

Sternocleidomastoid

The sternocleidomastoid is a muscle in the neck that acts to flex and rotate the head. It also aids in forced inhalation by elevating the sternum, increasing the anteroposterior diameter of the thoracic cavity.

The sternocleidomastoid muscle.

Scalene Muscles

The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior. They elevate the first and second ribs, aiding in inspiration by increasing the diameter of the thoracic cavity.

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The scalene muscles.

Pectoralis Major

The pectoralis major is a thick, fan-shaped muscle situated at the chest (anterior) of the human body. It aids in forced inspiration by increasing the transverse dimension of the thoracic cavity.

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The pectoralis major muscle.

See Also

• Respiratory system
• Breathing
• Human anatomy