lisähengityslihasten

Lisähengityslihakset refer to a group of muscles that assist in the process of breathing, particularly during more strenuous activity or when the primary respiratory muscles are insufficient. While the diaphragm and intercostal muscles are the main drivers of normal, resting respiration, these accessory muscles become active when a greater volume of air needs to be moved in or out of the lungs.

Accessory muscles can be broadly categorized into those that aid in inspiration (inhalation) and those that aid in expiration (exhalation). During forced inhalation, muscles such as the sternocleidomastoid, scalenes, pectoralis major and minor, and the serratus anterior can contract to elevate the rib cage and sternum, further expanding the thoracic cavity. This allows for a greater intake of air.

Forced exhalation, on the other hand, involves the contraction of muscles like the abdominal muscles (rectus abdominis, external and internal obliques, transversus abdominis) and the internal intercostal muscles. These muscles work to decrease the volume of the thoracic cavity, forcing air out of the lungs more rapidly and completely.

The involvement of lisähengityslihasten is a normal physiological response to increased metabolic demand, such as during exercise, or in individuals experiencing respiratory distress or disease. Their activation signifies a greater effort required to maintain adequate gas exchange. In certain medical conditions, such as asthma or COPD, the sustained use of these muscles can lead to fatigue and discomfort, often observed as visible retractions of the chest and neck during breathing.