Bronchopulmonary Segments

Anatomically, the trachea extends from the cricoid cartilage (level of C6/C7) to the carina (T4/T5) and is reinforced anteriorly by approximately 20 semicircular, cartilaginous rings. The trachea divides into the right and left mainstem bronchi which further divide into secondary bronchi (RUL, RML, RLL, LUL, and LLL). Of note, the bronchus intermedius (BI) is a continuation of the right mainstem bronchus distally.

  • Right mainstem
    • Right upper lobe (RUL)
      • Apical
      • Anterior
      • Posterior
    • Right middle lobe (RML)
      • Lateral
      • Medial
    • Right lower lobe (RLL)
      • Superior (common site for aspiration in supine position)
      • Medial-basal
      • Lateral-basal
      • Anterior-basal
      • Posterior-basal (common site for aspiration in standing position)
  • Left mainstem
    • Left upper lobe (LUL)
      • Apicoposterior (combined segments)
      • Anterior
      • Lingular segments
        • Superior lingular
        • Inferior lingular
    • Left lower lobe (LLL)
      • Apical
      • Anteromedial basal (combined segments)
      • Lateral basal
      • Posterior basal

Each of the secondary bronchi give rise to several bronchopulmonary segments – the functional anatomic unit of the lung parenchyma. The right and left lung each have ten of these segments which, in turn, each have a tertiary bronchus, pulmonary artery, and bronchial artery supply. These segments can be identified radiographically and often constitute the boundaries for surgical resection.

It’s important to understand this anatomy during bronchoscopy and airway instrumentation, so we know exactly where we are in the tracheobronchial tree and can communicate the location of our findings more precisely with colleagues.

Drop me a comment below with questions! 🙂

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2 Comments
  1. Sharon says

    I ❤️ you Rishi! I could’ve really used this, and you when I was in school. I love the way you’ve explained it. Makes perfect sense. Simply put, and perfection ????

    1. Rishi says

      Thanks so much for the sweet comment, Sharon! Glad it helped! 🙂