Intercostal Muscles Anatomy

Intercostal Muscles

Location and Function

• Located between the ribs in the thoracic cavity
• Responsible for expanding and contracting the chest cavity during breathing
• Play a crucial role in inspiration and expiration

Types of Intercostal Muscles

• External Intercostal Muscles:
  • Originate from the rib above and insert into the rib below
  • Assist in inspiration by elevating the ribs and expanding the chest cavity
• Internal Intercostal Muscles:
  • Originate from the rib above and insert into the rib below
  • Assist in expiration by depressing the ribs and reducing the chest cavity
• Innermost Intercostal Muscles:
  • Thin layer of muscle fibers between the internal intercostal muscles and the endothoracic fascia
  • Assist in expiration by depressing the ribs and reducing the chest cavity

Nerve Supply

• Intercostal Nerves: originate from the thoracic spinal nerves (T1-T12) and supply the intercostal muscles
• Phrenic Nerve: supplies the diaphragm, which works in conjunction with the intercostal muscles during breathing

Actions

• Inspiration: external intercostal muscles contract, elevating the ribs and expanding the chest cavity
• Expiration: internal intercostal muscles and innermost intercostal muscles contract, depressing the ribs and reducing the chest cavity

Clinical Relevance

• Injury or paralysis: can lead to respiratory difficulties and impaired breathing
• Surgical procedures: may involve the intercostal muscles, such as thoracic surgery or chest tube insertion

Intercostal Muscles

Location and Function

• Intercostal muscles are situated between the ribs in the thoracic cavity
• They facilitate breathing by expanding and contracting the chest cavity during inspiration and expiration

Types of Intercostal Muscles

• External Intercostal Muscles:
  • Originate from the rib above and insert into the rib below
  • Assist in inspiration by elevating the ribs and expanding the chest cavity
• Internal Intercostal Muscles:
  • Originate from the rib above and insert into the rib below
  • Assist in expiration by depressing the ribs and reducing the chest cavity
• Innermost Intercostal Muscles:
  • Located between the internal intercostal muscles and the endothoracic fascia
  • Assist in expiration by depressing the ribs and reducing the chest cavity

Nerve Supply

• Intercostal Nerves:
  • Originate from the thoracic spinal nerves (T1-T12)
  • Supply the intercostal muscles
• Phrenic Nerve:
  • Supplies the diaphragm
  • Works in conjunction with the intercostal muscles during breathing

Actions

• Inspiration:
  • External intercostal muscles contract
  • Ribs are elevated and the chest cavity expands
• Expiration:
  • Internal intercostal muscles and innermost intercostal muscles contract
  • Ribs are depressed and the chest cavity reduces

Clinical Relevance

• Injury or paralysis of intercostal muscles can lead to:
  • Respiratory difficulties
  • Impaired breathing
• Surgical procedures involving intercostal muscles include:
  • Thoracic surgery
  • Chest tube insertion

Learn about the location, function, and types of intercostal muscles, including their role in breathing and respiration.