Lateral Chest X-Ray Analysis by Rishi Agarwal

Introduction

• Aim: Overview of how to read a lateral chest x-ray.
• Focus: Basics rather than exhaustive anatomy.
• Importance: Often, abnormalities are more visible on frontal views, but lateral views are crucial for localization.

Key Areas of Focus

Hylar Area

• Hyla: Right and left hyla superimposed.
• Lucency: Central area = left upper lobe bronchus, important as a landmark for anatomical structures.
  • Structures:
    • Right Pulmonary Artery: Anterior to left upper lobe bronchus (9 o'clock position).
    • Left Pulmonary Artery: Arching over the left upper lobe bronchus (10 to 3 o'clock).
• Infrahylar Window: Lucent area inferior to the left upper lobe bronchus.
  • Pathology: Opacity indicates hylar or mediastinal lymphadenopathy.

Clear Spaces

1. Retro-sternal Clear Space

   • Location: Behind the sternum.
   • Abnormalities: Airspace disease in upper lobes, anterior mediastinal mass.

2. Retrotracheal Clear Space (Rader’s Triangle)

   • Location: Behind the trachea, bordered by spine, aortic arch, and trachea.
   • Abnormalities: Vascular anomalies, esophageal issues.

3. Retrocardiac Clear Space

   • Location: Behind the heart; ill-defined superior border.
   • Abnormalities: Lower lobe consolidation, masses, hiatal hernia.

Heart Assessment

• Right Ventricle: Sits about a third of the way up the sternum (normal).
  • Signs of Hypertrophy: Encroaching upon retrosternal clear space.
• Left Ventricle: Posterior border visible.
  • Signs of Hypertrophy: Retrocardiac clear space smaller.
• Main Pulmonary Artery & Ascending Aorta: Poor visibility due to superimposition.
  • Aortic Enlargement: Common, especially in older patients.

Bones Evaluation

• Spine: Check for vertebral compression deformities.
• Sternum: Assess for fractures (often missed in frontal view).
• Ribs and Scapula: Not primary focus, but may identify fractures.

Diaphragm Inspection

• Location: Diaphragm visible in the lateral view.
• Costophrenic Angles: Check for blunting, indicating pleural effusion.
  • Sensitivity: Lateral view is better for detecting small pleural fluid amounts.

Conclusion

• Final Checks: Look below the diaphragm for upper abdominal abnormalities.
• Engagement: Viewers encouraged to ask questions in comments.