Anatomy of the Heart

Overview of Heart Surfaces

• Anterior Surface: Front view of the heart.
• Posterior Surface: Back of the heart.
• Inferior Surface: Bottom part of the heart.
• Apex: Bottom tip of the heart.
• Superior Surface (Base): Top part, pointing towards the right shoulder.

Key Structures

Auricles

• Left Auricle: Fatty pouch with muscle tissue to help squeeze blood into the atrium.
• Right Auricle: Similar structure on the right side.

Major Vessels

• Pulmonary Trunk: Carries deoxygenated blood from the right ventricle to the lungs.
• Aorta: Main artery carrying oxygenated blood from the heart to the body.
  • Ascending Aorta
  • Aortic Arch
    • Brachiocephalic Artery: Splits into right subclavian and right common carotid.
    • Left Common Carotid Artery
    • Left Subclavian Artery
• Superior Vena Cava: Large vein bringing deoxygenated blood to the right atrium.
  • Formed by merging of right and left brachiocephalic veins.
  • Accompanied by azygos vein.

Pulmonary Circulation

• Pulmonary Arteries: Carry deoxygenated blood from the heart to the lungs.
  • Right Pulmonary Artery
  • Left Pulmonary Artery
• Pulmonary Veins: Return oxygenated blood from the lungs to the heart.
  • Left Pulmonary Veins
  • Right Pulmonary Veins

Coronary Circulation

• Right Coronary Artery

  • Marginal Artery: Supplies right ventricle.
  • Posterior Interventricular Artery: Runs through the posterior interventricular sulcus.

• Left Coronary Artery

  • Anterior Interventricular Artery (Left Anterior Descending)
    • Common site of myocardial infarction.
  • Circumflex Artery: Supplies lateral walls of left ventricle.

Veins

• Great Cardiac Vein: Runs alongside the anterior interventricular artery.
• Small Cardiac Vein: Drains the right side.
• Middle Cardiac Vein: Runs alongside the posterior interventricular artery.
• Coronary Sinus: Collects blood from cardiac veins and empties into the right atrium.

Cardiac Chamber Anatomy

Right Atrium

• Tricuspid Valve: Separates right atrium and ventricle.
• Chordae Tendineae: Collagen cords anchoring valve leaflets.
• Papillary Muscles: Anchor chordae tendineae.
• Fossa Ovalis: Remnant of fetal foramen ovale.
• Opening of Coronary Sinus

Right Ventricle

• Pulmonary Semilunar Valve: Prevents backflow from pulmonary trunk.
• Trabeculae Carneae: Muscle lining.

Left Atrium

• Mitral Valve (Bicuspid Valve): Separates left atrium and ventricle.
• Openings for Pulmonary Veins

Left Ventricle

• Aortic Semilunar Valve: Prevents backflow from aorta.
• Interventricular Septum: Wall between ventricles.

Heart Wall and Layers

• Myocardium: Cardiac muscle tissue.
• Endocardium: Lines the inner chambers and valves.
• Epicardium (Outer Layer): Made of mesothelium.

Special Structures

• Ligamentum Arteriosum: Remnant of fetal ductus arteriosus.
• Pectinate Muscles: Found in the walls of atria.

Anastomoses

• Provide collateral routes for blood flow between different arteries, ensuring oxygen delivery despite blockages.
• Examples:
  • Between marginal artery and posterior interventricular artery.
  • Between circumflex artery and posterior interventricular artery.

Conclusion

An understanding of the heart's anatomy, circulation, and structure provides insight into its function and the importance of its components in maintaining efficient blood flow and oxygen delivery throughout the body.