Canonical Question

Procedure – Bronchoscopy

V5 C1.i Historical V4 F1.i, X.v 2 appearances

Master answer

Tracheobronchial Tree

Trachea →
Primary main bronchi →
Lobar bronchi →
segmental bronchi (each supplies one bronchopulmonary segment) →
divide dichotomously→→→→
terminal bronchioles →
respiratory bronchioles →
2-11 alveolar ducts →
alveoli

Trachea

Midline. 10-12 cm long 15-20mm diameter.
From Cricoid (C6 level) to bifurcation (T4-T6 level)
16-20 C-shaped cartilage rings
- Vertical fibroelastic tissue, and posterior trachealis muscle
Arterial supply: Upper 2/3 – Inferior thyroid artery, Lower 1/3 Bronchial artery
Venous drainage: Inferior thyroid vein
Lymphatics: Drain into deep cervical, pre-tracheal, paratracheal lymph nodes
Nerve supply: Recurrent laryngeal nerve, Sympathetic fibres from middle cervical ganglion

Bronchi

Supplied by bronchial arteries which run along the bronchi (with vessels from pulmonary circulation)
Drains into bronchial veins
Similar innervation as trachea
A bronchopulmonary segment is a portion of lung supplied by a specific segmental bronchus and arteries.

Right main bronchus

2cm long, I.D. 10-16mm
Shorter, wider, more nearly vertical than left

Branches:

Right upper lobe
- Apical
- Anterior
- Posterior
Bronchus intermedius
- Middle lobe
  - Medial
  - Lateral
- Lower lobe
  - Superior
  - Medial basal
  - Anterior basal
  - Lateral basal
  - Posterior basal

Left main bronchus

4-5cm long, I.D. 8-14mm
Crosses anterior to the esophagus, which it indents.

Branches:

Left upper lobe
- Apicoposterior
- Anterior
Lingular
- Superior
- Inferior
Left lower lobe
- Superior
- Anterior basal
- Lateral basal
- Posterior basal

Lining Epithelium

Trachea → Terminal bronchioles: ciliated pseudostratified columnar epithelium

Respiratory bronchioles → alveolar ducts → alveoli: Non ciliated cuboidal epithelium

Sources: Nunn’s Applied Respiratory Physiology, West’s Respiratory Physiology, Berne and Levy Physiology

JC 2019

Answer by JC

Exam appearances

Exam	Exact wording	Relationship	Success
2019B Q05	Describe the anatomical course and relations of the trachea and bronchial tree (to the level of the segmental bronchi).	historical_member	—
2016B Q24	Outline the tracheal (60% of marks) and left and right main bronchial anatomy (40% of marks) in an adult.	historical_member	—