External intercostal muscle

External Intercostal Muscles

The External Intercostal Muscles (shown in red). Image from Gray's Anatomy.

The External Intercostal Muscles are a group of muscles located between the ribs. They are one of the three layers of intercostal muscles that assist in the mechanical aspect of respiration.

Structure

The External Intercostal Muscles extend from the lower border of a rib above to the upper border of the rib below, becoming continuous with the external oblique muscle of the abdomen. They are responsible for the elevation of the ribs, increasing the volume of the thoracic cavity during inhalation.

Function

The primary function of the External Intercostal Muscles is to aid in respiration. During inhalation, these muscles contract, pulling the ribs upward and outward, expanding the chest cavity and allowing the lungs to expand. During exhalation, these muscles relax, allowing the ribs and lungs to return to their original position.

Clinical significance

Damage or injury to the External Intercostal Muscles can result in difficulty breathing and pain during respiration. Conditions such as intercostal neuralgia and rib fractures can affect the function of these muscles.

See also

• Internal intercostal muscles
• Intercostal nerves
• Respiratory system

External links

• AnatomyZone: External Intercostal Muscles