The muscles within the rib cage, also known as the thoracic wall, are crucial for respiration and chest stability. They include several key muscle groups.
Muscles of the Rib Cage
The rib cage muscles primarily consist of five distinct muscle groups which are all involved in breathing and maintaining the structure of the chest. These muscles are:
1. External Intercostal Muscles
These muscles are located between the ribs. They help with inhalation by expanding the rib cage.
2. Internal Intercostal Muscles
Also positioned between the ribs, the internal intercostals are involved in exhalation and assist in the compression of the rib cage.
3. Innermost Intercostal Muscles
These muscles are the deepest layer of intercostal muscles, running in a similar direction as the internal intercostals, and aid in respiration.
4. Subcostalis
Located on the inner surface of the rib cage near the spine, these muscles assist in lowering the ribs and are involved in exhalation.
5. Transversus Thoracis
Found on the inner surface of the anterior chest wall, this muscle group helps to depress the ribs during exhalation.
Summary Table of Rib Cage Muscles
| Muscle Name | Location | Function |
|---|---|---|
| External Intercostals | Between the ribs, outer layer | Elevates ribs during inhalation |
| Internal Intercostals | Between the ribs, middle layer | Depresses ribs during exhalation |
| Innermost Intercostals | Between the ribs, innermost layer | Assists in respiration |
| Subcostalis | Inner surface of the posterior rib cage | Depresses ribs during exhalation |
| Transversus Thoracis | Inner surface of the anterior chest wall | Depresses ribs during exhalation |
These five muscle groups work in coordination to facilitate breathing and maintain the structural integrity of the rib cage. Knowing their location and function is key to understanding respiration and the overall biomechanics of the thorax.
