External and Internal Intercostal Muscles

Internal and External Intercostal Muscles

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External and Internal Intercostal MusclesWhat do the names, internal and external intercostal muscles, mean?

Internal comes from the Latin word internus, which means within.
External means outside of.
The word intercostal comes from the Latin words inter, which means between, and costa, which means rib.
The internal intercostals then, are muscles between the ribs and located inside a structure, while the external intercostals are muscles between the ribs and located on the outside of a structure.

In the case of the intercostals, they are internal or external relative to one another.

Where do the internal and external intercostal muscles attach?


The internal intercostals originate and insert between adjacent ribs.
The external intercostals originate on the inferior border of the rib above.


The external intercostals insert on the superior border of the rib below.

What actions do the internal and external intercostal muscles do?

The internal intercostals bring the ribs down during forced expiration.
The external intercostals elevate the ribs in inspiration.
Keep in mind that the abdominal muscles all have a role to play in forced exhalation.

Poses where we may be more aware of the internal and external intercostal muscles and breathing in yoga:

Internal and External Intercostal Muscles in Marichyasana C

In postures like marichyasana C, we may notice that it is more difficult to breathe. The abdomen is compressed during the twist, so the ribs need to move more during the act of inhalation to accommodate that. The ribcage itself is also under more pressure from being stretched. This makes it harder for the ribs to separate and allow air in.

Internal and External Intercostal Muscles in Parighasana

A posture such as parighasana lengthens each side of the body. The ribs are being pulled apart from one another and this would lengthen the intercostals.

yoga anatomy book cover

Many of the concepts in this article are discussed in:
Functional Anatomy of Yoga


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david keil yoga anatomyThis website is simply about delivering yoga anatomy to the yoga community in a simple and understandable way. It has always been about you, the reader, understanding the complexity and diversity of our own humanness as well as our anatomy.

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