Cardiovascular ANATOMY - Diaphragm and Intercostal Muscles

طب بشري | Medicine 


جامعة الفيصل
  • 2025-03-28

Diaphragm

The diaphragm is a dome-shaped skeletal muscle that separates the thoracic cavity from the abdominal cavity. It is the primary muscle of respiration and contributes indirectly to cardiovascular function by influencing intrathoracic pressure.

Structure

  • Origin: The diaphragm originates from multiple points:

    • Xiphoid process of the sternum.

    • Lower six costal cartilages.

    • Lumbar vertebrae (via the crura).

  • Insertion: It inserts into the central tendon, a strong aponeurotic structure.

  • Parts:

    • Peripheral muscular part.

    • Central tendinous part.

Function

  • Respiration: During inspiration, the diaphragm contracts and flattens, increasing the vertical diameter of the thoracic cavity. This creates negative pressure, allowing air to enter the lungs.

  • Cardiovascular Impact: The diaphragm's movement affects venous return to the heart by altering intrathoracic pressure, aiding in blood circulation.

Innervation

  • Phrenic Nerve: Arises from C3, C4, and C5 spinal nerves ("C3, C4, and C5 keep the diaphragm alive").

  • Sensory Innervation: The phrenic nerve provides sensory input to the central part, while the peripheral parts receive sensory innervation from lower intercostal nerves.

Clinical Relevance

  • Diaphragmatic Paralysis: Can result from phrenic nerve damage, leading to respiratory distress.

  • Hiatal Hernia: Occurs when abdominal organs protrude through the diaphragm.

 

Intercostal Muscles

The intercostal muscles are located between the ribs and are essential for respiration. They consist of three layers: external, internal, and innermost intercostal muscles.

Structure

  • External Intercostal Muscles:

    • Fibers run downward and forward.

    • Extend from the inferior border of one rib to the superior border of the rib below.

    • Function: Elevate ribs during inspiration, increasing thoracic volume.

  • Internal Intercostal Muscles:

    • Fibers run downward and backward.

    • Extend from the subcostal groove of one rib to the upper border of the rib below.

    • Function: Depress ribs during forced expiration.

  • Innermost Intercostal Muscles:

    • Incomplete layer.

    • Function: Assist external and internal intercostal muscles.

Function

  • Respiration:

    • Contraction of intercostal muscles changes the dimensions of the thoracic cavity.

    • External intercostals are active during inspiration, while internal intercostals are active during expiration.

Innervation

  • Intercostal Nerves:

    • Derived from the anterior rami of thoracic spinal nerves (T1-T11).

    • Provide motor and sensory innervation to the intercostal muscles and overlying skin.

Clinical Relevance

  • Intercostal Neuralgia: Pain along the intercostal nerves, often due to trauma or inflammation.

  • Chest Wall Injuries: Can impair the function of intercostal muscles, affecting respiration.

 

Integration in Cardiovascular Anatomy

While primarily involved in respiration, the diaphragm and intercostal muscles indirectly support cardiovascular function:

  • Venous Return: Diaphragmatic movement enhances venous return to the heart.

  • Thoracic Pressure Regulation: Changes in thoracic pressure during respiration influence cardiac output and blood flow.

هل كان الشرح مفيد؟

avatar
Mohammed Adel

 

  • حضوري وجها لوجه في الرياض/السعوديةSA
  • عن بعد/اونلاين
  • شروحات مشابهة

    • طب بشري | Medicine
    • طب بشري | Medicine
    • تمريض | Nursing
    • علاج تنفسي | respiratory therapy
    • تمريض و علاج تنفسي | Nursing and respiratory therapy
    • علوم صحية | Health sciences
    • طب أسنان | Dentistry
    • صيدلة | Pharmacy
    • كيمياء عضوية | Organic chemistry
    • كيمياء حيوية | Biochemistry
    • ادوية | Pharmacology
    محتاج مساعدة باختيار المدرس الافضل؟ تواصل مع فريقنا الان لمساعدتك بتأمين افضل مدرس
    ماهو التخصص الذي تبحث عنه؟
    اكتب هنا...