Internal Intercostals

Definition

The internal intercostals are a set of muscles located between the ribs that play a crucial role in the process of breathing and the movement of the abdominal wall. These muscles are part of the axial musculature and contribute to the overall function of the thoracic and abdominal regions.

5 Must Know Facts For Your Next Test

1. The internal intercostals are located deep to the external intercostals and run in a different direction, creating a crisscross pattern.
2. During inspiration, the internal intercostals contract, pulling the ribs inward and upward, which expands the thoracic cavity and facilitates the inhalation of air.
3. The internal intercostals also play a role in forced expiration, contracting to pull the ribs downward and inward, which helps to expel air from the lungs.
4. In addition to their respiratory functions, the internal intercostals contribute to the stability and movement of the abdominal wall, working in coordination with the abdominal muscles.
5. The innervation of the internal intercostals is provided by the intercostal nerves, which are branches of the thoracic spinal nerves.

Review Questions

• Describe the role of the internal intercostals in the process of breathing.
  • The internal intercostals are responsible for the mechanical aspects of breathing. During inspiration, they contract, pulling the ribs inward and upward, which expands the thoracic cavity and facilitates the inhalation of air. Conversely, during forced expiration, the internal intercostals contract to pull the ribs downward and inward, helping to expel air from the lungs. This coordinated movement of the ribs, driven by the internal intercostals, is essential for the process of breathing.
• Explain the relationship between the internal intercostals and the abdominal wall.
  • In addition to their respiratory functions, the internal intercostals also contribute to the stability and movement of the abdominal wall. They work in coordination with the abdominal muscles, such as the transversus abdominis and the internal oblique, to maintain the integrity of the abdominal wall and facilitate trunk movements. The internal intercostals' ability to pull the ribs inward and downward helps to increase intra-abdominal pressure, which is important for activities like coughing, sneezing, and abdominal bracing.
• Analyze the significance of the internal intercostals' unique anatomical arrangement and innervation.
  • The internal intercostals are positioned deep to the external intercostals, creating a crisscross pattern that allows for efficient and coordinated movement of the ribs during breathing. This arrangement, combined with their innervation by the intercostal nerves (branches of the thoracic spinal nerves), enables the internal intercostals to precisely control the movement of the ribs, which is crucial for the mechanical processes of inspiration and expiration. The strategic location and innervation of the internal intercostals ensure their ability to effectively contribute to both respiratory and abdominal functions, highlighting their importance in the overall integration of the thoracic and abdominal regions.

Related terms

Intercostal Muscles: The intercostal muscles are a group of muscles that fill the spaces between the ribs, consisting of the internal and external intercostals.

Respiratory Muscles: The respiratory muscles are a group of skeletal muscles responsible for the mechanical processes of breathing, including the diaphragm, intercostal muscles, and abdominal muscles.

Abdominal Wall: The abdominal wall is the layered structure that encloses the abdominal cavity and plays a role in various functions, such as respiration, posture, and trunk movement.