Cardiothoracic Surgery: Anatomy

Pulmonary Anatomy

Lung Structure

  • Right Lung (55%)
    • 3 Lobes:
      • Right Upper Lobe (RUL)
      • Right Middle Lobe (RML)
      • Right Lower Lobe (RLL)
    • Minor/Horizontal Fissure: Separates Upper from Middle Lobes
    • Major/Oblique Fissure: Separates Upper/Middle Lobes from the Lower Lobe
  • Left Lung (45%)
    • 2 Lobes:
      • Left Upper Lobe (LUL) – Includes the Lingula
      • Left Lower Lobe (LLL)
    • Oblique Fissure: Separates the Two Lobes

Lung Anatomy 1

Pulmonary Arteries

  • Supply Deoxygenated Blood to Become Oxygenated
  • From the Right Ventricle

Bronchial Arteries

  • Supply Oxygenated Blood
  • Higher Pressure – 600% of Pulmonary Arteries
  • Anatomical Variations (Cauldwell Types):
    • Type 1: 1 Right & 2 Left (41% – Most Common)
    • Type 2: 1 Right & 1 Left (21%)
    • Type 3: 2 Right & 2 Left (20%)
    • Type 4: 2 Right & 1 Left (10%)
  • Most Common Source:
    • Left – From the Aorta
    • Right – From a Common Trunk with the Posterior Intercostal Artery

Bronchial Artery Variations; Type 1-4 (Left-to-Right) 2

Mediastinal Anatomy

Mediastinum Contents

  • Anterior Mediastinum:
    • Thymus
  • Middle Mediastinum:
    • Heart
    • Trachea
    • Ascending Aorta
    • SVC
    • Pulmonary Trunk
  • Posterior Mediastinum:
    • Esophagus
    • Descending Aorta
    • Azygous
    • Thoracic Duct
  • Superior Mediastinum:
    • Esophagus & Trachea
    • Aortic Arch & Branches
    • Brachiocephalic Vein

Mediastinum 1

Cardiac Vasculature

  • Primary Branches
    • Left Coronary Artery (LCA)
      • Left Anterior Descending (LAD)
      • Left Circumflex (LCX)
    • Right Coronary Artery (RCA)
      • Posterior Descending Artery (PDA)
        • Determines Dominance
        • 90% from RCA
  • Nodal Branches
    • SA Node: 50% from RCA
      • Located at Junction of Right Atrium & SVC
    • AV Node: 90% from RCA

Coronary Arteries 3

Thoracic Vasculature

Thoracic Duct

  • Origin: Cisterna Chyli at L1-2
  • Enters Chest Through: Aortic Hiatus; Along Right Side
  • Crosses Midline: T4-5
  • Drains Lymph into the Left Subclavian Vein Near IJ Junction
  • Flow: 1.5-2.5 L/Day
    • Increases with Oral Fat Intake (Especially Long-Chain Triglycerides)

Nerves

Tracheal Blood Supply 4

Thoracic Duct 1

Phrenic & Vagus Nerves 1

Lymph Node Stations

Supraclavicular

  • Station 1: Low Cervical, Supraclavicular & Sternal Notch

Superior Mediastinal Nodes

  • Station 2: Paratracheal – Upper
  • Station 3: Prevascular & Retrotracheal
  • Station 4: Paratracheal – Lower

Aortic Nodes

  • Station 5: Subaortic (Aortopulmonary Window)
  • Station 6: Para-aortic

Inferior Mediastinal Nodes

  • Station 7: Subcarinal
  • Station 8: Paraesophageal – Below Carina
  • Station 9: Pulmonary Ligament

N1 Nodes

  • Station 10: Hilar
  • Station 11: Interlobar
  • Station 12: Lobar
  • Station 13: Segmental
  • Station 14: Sub-Segmental

Thoracic Lymph Node Stations 5

References

  1. Gray H. Anatomy of the Human Body (1918). Public Domain.
  2. Pourdowlat G, Varasteravan H, Kashani BS, Bagheri A. A 58-year-old woman with recurrent hemoptysis after successful bronchial artery embolization. Tanaffos. 2014;13(1):57-60. (License: CC BY-NC-3.0)
  3. Haggstrom M. Wikimedia Commons. (License: CC BY-SA-3.0)
  4. Allen MS. Surgery of the Trachea. Korean J Thorac Cardiovasc Surg. 2015 Aug;48(4):231-7. (License: CC BY-NC-3.0)
  5. Pultrum BB, van der Jagt EJ, van Westreenen HL, van Dullemen HM, Kappert P, Groen H, Sietsma J, Oudkerk M, Plukker JT, van Dam GM. Detection of lymph node metastases with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging in oesophageal cancer: a feasibility study. Cancer Imaging. 2009 Apr 6;9(1):19-28. (License: CC BY-4.0)