What does the term "Accessory Muscle Use" refer to in the context of breathing?

The term "Accessory Muscle Use" in the context of breathing refers to utilizing additional muscles beyond the primary respiratory muscles, such as the diaphragm and intercostal muscles, to assist in the process of breathing. This situation typically arises when a person is experiencing difficulty with normal breathing, often due to conditions like asthma, COPD, or respiratory distress.

In such cases, the body recruits accessory muscles—such as those in the neck (sternocleidomastoid), shoulders (trapezius), and abdomen—to facilitate airflow and improve ventilation. This mechanism reflects an increased effort to breathe, highlighting that the individual is struggling, as the primary muscles alone are insufficient to maintain adequate respiratory function. Recognizing accessory muscle use is an important clinical sign that can indicate the severity of respiratory distress and guide further assessment and intervention.