intercostal muscle

This term is a precise anatomical designation used primarily in medical, biological, and clinical contexts. It describes the specific musculature situated within the intercostal spaces, which are the gaps between the ribs. The term is highly technical and rarely appears in casual conversation unless discussing respiratory health or thoracic surgery.

Because it refers to a specific anatomical structure, it is used in a descriptive sense to explain the mechanics of breathing. It is often paired with adjectives such as internal or external to specify the exact layer of muscle being discussed, as these layers perform opposing functions during the respiratory cycle.