The Intercostal Muscles

The Intercostal Muscles:

There are spaces present in-between the ribs and these are known as the intercostal spaces. Due to the fact that there are 12 ribs, there are 11 intercostal spaces and these spaces contain different nerves, blood vessels and muscles. The muscles that tend to be found in these gaps are the intercostal muscles.

The intercostal muscles are various collections of muscles that help to form and move the chest wall and can be found running between the ribs. There are three principal layers:

* The external intercostal muscles – these are on the outer layer. These originate on ribs 1-11 and their insertions are on ribs 2-12. These muscles aid in forced and quiet inhalation and are responsible for the expansion of the transverse dimension of the thoracic cavity as well as the elevation of the ribs. They are innervated by the intercostal nerves and provided by the intercostal veins and arteries, with their fibres running in opposite directions.

* The internal intercostal muscles – these are on the inner layer. These originate on ribs 1-11 and their insertions are on ribs 2-12. These muscles ain in forced expiration and are responsible for decreasing the transverse dimensions of the thoracic cavity as well as the depression of the ribs. They are innervated by the intercostal nerves and provided by the intercostal veins and arteries, with their fibres running in opposite directions.

* The innermost intercostal muscle – this muscle is found in the deepest layers of the internal intercostal muscles but is separated from them by the ‘neurovascular bundle’.


The left side of the picture shows the inner layer of the intercostal muscles whilst the right side shows the outer layer.

The main involvement of the intercostal muscles in with the mechanical aspect of breathing as they help in expanding and shrinking the capacity of the chest when breathing.
External: These muscles create an increased lung volume by pulling the ribs up and therefore draw air into the lungs. Internal: These muscles create a decreased lung volume by bringing the ribs closer to one another expelling the air out of the lungs.

These muscles aiding with the respiration process it what makes them so important to a performer. It is the usage of these muscles that enhance proper breathing and makes it possible for a reduction of strain on the vocal cords. They also help for greater breath control. Both of these are needed in both singing and acting, for example performing a monologue or when singing a song. My understanding of these muscles is important as to ensure that I look after my body and understand how to control them in order to improve my vocal technique.