Lung Auscultation: Normal and Abnormal Breath Sounds

Objectives

• Understand lung anatomy, crucial for accurate auscultation.
• Learn specific auscultation sites and their corresponding lung lobes.
• Differentiate between normal breath sounds and abnormal breath sounds.

Lung Anatomy Overview

Anterior Chest

• Upper Lobes: Predominantly in the anterior part.
• Landmarks:
  • Clavicle and intercostal spaces are key for identifying lobes.
  • Right Lung:
    • Three lobes: right upper, middle, and lower lobes.
    • Horizontal and oblique fissures separate these lobes.
  • Left Lung:
    • Two lobes: left upper and lower lobes.
• Trachea: Branches into bronchi and further into bronchioles where gas exchange occurs.

Posterior Chest

• Lower Lobes: Predominantly in the posterior part.
• Landmarks:
  • C7 to T10 vertebrae are key for auscultation.
  • Difficult to assess the right middle lobe posteriorly.

Tips for Auscultation

• Use the diaphragm of the stethoscope directly on the skin for clear sounds.
• Special Considerations for Women: Raise the breast to properly auscultate.
• Method:
  • Full cycle of inspiration and expiration.
  • Note the pitch, sound quality, and duration.
  • Compare sides systematically from apex to base.
• Patient Position:
  • Sitting up for access to front and back.
  • Arms forward to separate shoulder blades for better access.

Auscultation Sites

Anterior Chest

• Apex: Above clavicle.
• Upper Lobes: Second intercostal space, midclavicular line.
• Right Middle Lobe: Fourth intercostal space, midclavicular line.
• Lower Lobes: Sixth intercostal space, midaxillary line.

Posterior Chest

• Apex to Upper Lobes: Above scapula to T3.
• Lower Lobes: T3 to T10.

Normal Breath Sounds

Types of Normal Breath Sounds

• Bronchial:

  • Heard anteriorly, over the tracheal area.
  • High pitched, loud, with shorter inspiration than expiration.

• Bronchovesicular:

  • Heard both anteriorly and posteriorly.
  • Medium pitch, equal inspiration, and expiration.

• Vesicular:

  • Heard throughout peripheral lung fields.
  • Low pitch, soft, with longer inspiration than expiration.

Abnormal Breath Sounds

Continuous Sounds (>2 seconds)

• High-Pitch Polyphonic Wheeze: High pitched, musical, mainly on expiration.
• Low-Pitch Monophonic Wheeze: Low pitch, whistle-like, mainly on expiration.
• Stridor: High pitch, harsh, on inspiration due to airway obstruction.

Discontinuous Sounds (<2 seconds)

• Coarse Crackles: Low pitch, wet bubbling sound, mainly on inspiration.

• Fine Crackles: High pitch, crackling, fire sound, mainly on inspiration.

• Pleural Friction Rub: Low pitch, harsh grating sound, on both inspiration and expiration.

  • Differentiate from cardiac rubs by having the patient hold their breath.

Additional Resources

• Access free quizzes and additional videos for further learning.