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Approach: nasal/oral (if not intubated) or via ETT/LMA/tracheostomy tube.


Indications: therapeutic/diagnostic/intubation aid.


The airways follow a branching tree pattern of approximately 23 generations from the trachea to the alveolar sacs. Only four to five can be visualized via bronchoscopy.

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Segmentation of the Lungs
Right lungLeft lung
Lobes (3)Segments (10)Lobes (2)Segments (8)
Upper lobeApicalUpper lobeApicoposterior
Middle lobeMedialSuperior lingula
LateralInferior lingula
Lower lobeSuperiorLower lobeSuperior
Medial basalAnteromedial basal
Anterior basal
Lateral basalLateral basal
Posterior basalPosterior basal

The lingula on the left corresponds to the right middle lobe. There are multiple variations, especially within the basal segments.

Figure 202-1. Upside-Down Schematic of the Tracheobronchial Tree
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Reproduced with permission from Doherty GM. Current Diagnosis & Treatment: Surgery. 13th ed. New York: McGraw-Hill; 2010. Figure 18-7. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.

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Bronchoscopic View of the Tracheobronchial Tree
  • From the inferior margin of the cricoid cartilage to the main carina
  • Dimensions: length–newborns ˜5.7 cm; adults ˜11 cm for males and 10 cm for females
  • Diameter–newborns ˜4–5 mm; adults ˜2.5 cm
  • Anterior wall (cartilaginous)–18–24 incomplete cartilaginous rings, open posteriorly
  • Posterior wall (membranous)–trachealis muscle

Figure 202-2

Image not available.

Main carinaSharp anteroposterior cartilaginous ridge at the bifurcation of the trachea

Figure 202-3

Image not available.

Right mainstem bronchus
  • Short, approximately 2 cm, runs more vertically than the left mainstem bronchus, it diverges at a 25–30° angle from midline
  • A foreign body will most likely enter here
Right upper lobe
  • The first branch off the lateral side of the right mainstem bronchus
  • It quickly trifurcates into three segments: apical, anterior, and posterior

Figure 202-4

Image not available.

Bronchus intermedius
  • The distal continuation of the right mainstem bronchus past the origin of the RUL
  • It runs for 2 cm and it bifurcates into the RML and RLL

Figure 202-5

Image not available.

Right middle lobe
  • It originates from the anterior and medial wall of the distal bronchus intermedius
  • It further bifurcates into the middle and lateral segments

Figure 202-6

Image not available.

Right lower lobe
  • Its superior segment takes off from the distal bronchus intermedius, on the posterior aspect, opposite from the origin of the RML
  • Descending past the superior segment, you will encounter the four basilar segments. First the medial basal segment (medial origin), and the other three segments on the lateral side in the A–L–P order: anterior, lateral, and posterior basal

Figure 202-7

Image not available.

Left mainstem bronchus
  • Diverges at a 45° angle from the midline
  • It is longer (4–5 cm) and narrower than the right mainstem bronchus
  • Distally, there is the left mainstem carina, which marks the bifurcation into the LUL and LLL

Figure 202-8

Image not available.

Left upper lobe
  • Appears superior to the left mainstem carina
  • It further subdivides ...

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