Lung Auscultation Lecture Notes

Objectives

• Understand lung anatomy to know what you're listening to.
• Learn specific auscultation sites and landmarks.
• Differentiate between normal and abnormal breath sounds with audio examples.

Lung Anatomy

• Anterior Chest
  • Mostly upper lobes
  • Right lung: 3 lobes (upper, middle, lower)
  • Left lung: 2 lobes (upper, lower)
  • Important landmarks: clavicle, intercostal spaces
• Posterior Chest
  • Mostly lower lobes
  • Right lung: upper and lower lobes
  • Left lung: upper and lower lobes
  • Landmark: C7 to T10 for auscultation sites

Tips for Auscultation

• Use the diaphragm of the stethoscope directly on skin to avoid rustling sounds from clothes.
• Ensure female patients raise breasts for better sound quality.
• Listen to both the anterior and posterior chest.
• Compare sides for full inspiration and expiration cycles.
• Evaluate pitch, sound quality, duration, and any adventitious sounds.
• Start from the top and work downwards comparing sides.
• Patient should breathe through the mouth slowly.

Auscultation Sites

• Anterior Chest
  • Apex: slightly above clavicle
  • Upper lobes: 2nd intercostal space, mid-clavicular line
  • Right middle lobe: 4th intercostal space, mid-clavicular line
  • Lower lobes: 6th to 7th intercostal space, mid-axillary line
• Posterior Chest
  • Apex: above scapula
  • Upper lobes: C7 to T3
  • Lower lobes: T3 to T10

Normal Breath Sounds

• Bronchial
  • Location: Anteriorly over trachea
  • High pitch, loud
  • Inspiration shorter than expiration
• Bronchovesicular
  • Location: Anteriorly (1st/2nd intercostal space), Posteriorly (between scapula)
  • Medium pitch
  • Inspiration equals expiration
• Vesicular
  • Location: Throughout peripheral lung fields
  • Low pitch, soft
  • Inspiration longer than expiration

Abnormal Breath Sounds

• Continuous Sounds
  • High-pitched Polyphonic Wheeze
    • Mostly on expiration, sometimes on inspiration
    • High-pitched musical sounds
  • Low-pitched Monophonic Wheeze
    • Mainly on expiration
    • Low-pitched whistle or whine
  • Stridor
    • On inspiration, high-pitched whistling/gasp
    • Indicates airway obstruction
• Discontinuous Sounds
  • Coarse Crackles
    • Heard on inspiration, sometimes expiration
    • Low pitch wet bubbling sound
  • Fine Crackles
    • Heard on inspiration
    • High-pitched crackling sound, does not clear with cough
  • Pleura Friction Rub
    • Heard on inspiration and expiration
    • Low-pitched harsh grating sound
    • Differentiate from pericardial friction rub by having the patient hold their breath

Conclusion

• Review and practice identifying these sounds.
• Use the free quiz and additional resources for further learning.