الثالثة أناتومي CVS (قبل التعديل)

Blood Supply of the Heart

• The heart is supplied by the right and left coronary arteries.
• The right coronary artery originates from the right aortic sinus and runs in the coronary groove between the right atrium and ventricle.
• The left coronary artery originates from the left aortic sinus and divides into the anterior interventricular artery and the circumflex artery.
• The anterior interventricular artery supplies both ventricles and the anterior 2/3 of the interventricular septum.
• The circumflex artery supplies the left ventricle and the left atrium.
• Right coronary dominance occurs when the posterior interventricular artery originates from the right coronary artery.
• Left coronary dominance occurs when the posterior interventricular artery arises from the circumflex artery.
• Right coronary dominance is found in 90% of individuals, whereas Left coronary dominance is found in 10%.

Veins of the Heart

• Venae cordis minimi are small veins that drain the heart and open into the chambers, mostly into the atria.
• Anterior cardiac veins are 3-4 veins that lie on the sternocostal surface of the right ventricle and drain directly into the anterior wall of the right atrium.
• The coronary sinus is the largest vein draining the heart and lies in the posterior part of the coronary groove between the back of the left atrium and the diaphragmatic surface of the left ventricle.
• The coronary sinus ends in the right atrium between the IVC opening and the tricuspid orifice.
• The great cardiac vein ascends in the anterior interventricular groove, curves, and ends in the posterior part of the coronary groove.
• The middle cardiac vein runs in the posterior interventricular groove.
• The small cardiac vein runs in the right posterior part of the coronary groove.
• The posterior vein of the left ventricle runs on the diaphragmatic surface of the left ventricle.
• The oblique vein of the left atrium descends obliquely on the back of the left atrium.

Nerve Supply of the Heart

• The heart is supplied by parasympathetic fibers from the vagus nerve and sympathetic fibers from the upper 5 thoracic segments of the spinal cord.
• These nerve fibers form the superficial and deep cardiac plexuses.

Clinical Correlation

• Angina pectoris is a condition caused by reduced blood supply to the heart due to narrowing of the coronary arteries.
• Myocardial infarction is a condition caused by the death of a part of the heart due to a cut off in blood supply.
• Pain fibers accompany the sympathetic nervous system, leading to pain referred to the T1 to T5 dermatomes which cover the chest and medial upper arm and forearm.
• This explains why myocardial ischemia (heart pain) is felt along the left side of the chest and inside of the left arm.

Blood Supply of the Heart

• Right Coronary Artery:
  • Originates from the right aortic sinus immediately above the aortic valve.
  • Courses in the coronary groove between the right atrium and ventricle.
  • Ends by anastomosing with the circumflex artery.
  • Supplies the:
    • Right conus artery: supplies the infundibulum.
    • Right atrial branches: right atrium.
    • Right ventricular branches: anterior and inferior surfaces of the right ventricle.
    • Marginal artery: inferior border of the heart, supplying both surfaces of the right ventricle.
    • Posterior interventricular branch (posterior descending): posterior surface of both ventricles and posterior 1/3 of the septum.
    • SA node in 60% of cases.
• Left Coronary Artery:
  • Originates from the left aortic sinus of the ascending aorta.
  • Passes between the pulmonary trunk and the left auricle.
  • Divides into two terminal branches:
    • Anterior Interventricular Artery (Left Anterior Descending):
      • Supplies both ventricles (anterior surface).
      • Gives the following branches:
        • Ventricular branches: both ventricles (anterior surface).
        • Septal branches: anterior 2/3 of the interventricular septum.
        • AV bundle and its branches.
    • Circumflex Artery:
      • Curves on the left border of the heart, continuing in the posterior coronary groove.
      • AV node in most cases.
      • Gives the following branches:
        • Atrial branches: left atrium.
        • Ventricular branches: left ventricle (anterior and posterior surfaces).
        • Artery to SA node: 40% of cases.
        • Left marginal artery: on the left margin of the heart, supplying the left ventricle.
• Coronary Dominance:
  • Right Coronary Dominance: posterior interventricular artery arises from the right coronary artery (90% of individuals).
  • Left Coronary Dominance: posterior interventricular artery arises from the circumflex branch of the left coronary artery (10% of individuals).

Veins of the Heart

• Venae Cordis Minimi:
  • Small veins from the wall of the heart opening directly into the four chambers, primarily the atria.
• Anterior Cardiac Veins:
  • 3-4 veins located on the sternocostal surface of the right ventricle.
  • Drain directly into the anterior wall of the right atrium.
• Coronary Sinus:
  • Largest vein draining the heart.
  • Located in the posterior coronary groove between the left atrium and the diaphragmatic surface of the left ventricle.
  • Ends in the right atrium between the IVC opening and the tricuspid orifice.
• Tributaries of the Coronary Sinus:
  • Great Cardiac Vein:
    • Ascends in the anterior interventricular groove with the anterior interventricular artery.
    • Curves left in the left coronary groove to the back of the heart with the circumflex artery.
  • Middle Cardiac Vein:
    • Runs in the posterior interventricular groove with the posterior interventricular artery.
  • Small Cardiac Vein:
    • Runs in the right posterior coronary groove with the right coronary artery.
  • Posterior Vein of Left Ventricle:
    • Runs on the diaphragmatic surface of the left ventricle.
  • Oblique Vein of the Left Atrium:
    • Descends obliquely on the back of the left atrium.

Nerve Supply of the Heart

• Parasympathetic Fibers: from the vagus nerve.
• Sympathetic Fibers: from the upper 5 thoracic segments of the spinal cord.
• Both types of nerves contribute to the superficial and deep cardiac plexuses.

Clinical Correlation

• Angina Pectoris: reduced blood supply due to narrowing of the coronary arteries.
• Myocardial Infarction: death of a portion of the heart due to complete blood supply blockage.
• Pain fibers accompanying the sympathetic nervous system (upper 5 thoracic segments) relay to the dorsal root of the spinal cord. This pain is interpreted in the brain and referred to dermatomes T1 to T5, covering the chest, medial upper arm, and forearm. Therefore, myocardial ischemia (heart pain) is felt along the left side of the chest and inside of the left arm.