CorpusHuman Anatomy
RespiratoryOrgan part

Bronchopulmonary segments

Segmenta bronchopulmonalia

Also known as: lung segments, pulmonary segments

Pyramidal, independently ventilated and perfused subdivisions of the lobes, each supplied by a segmental bronchus and artery — the anatomical basis of segmentectomy and of localising disease.

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Overview

A bronchopulmonary segment is the largest subdivision of a lobe. It is pyramid-shaped, with its apex towards the hilum and its base on the pleural surface, and is separated from adjacent segments by connective tissue septa. Each segment has its own segmental bronchus and segmental branch of the pulmonary artery running centrally, while tributaries of the pulmonary veins and lymphatics run in the intersegmental planes, draining adjacent segments.

Because a segment is a self-contained bronchovascular unit, a diseased segment can be removed with little bleeding or air leakage (segmentectomy), and aspiration, abscesses and tumours can be localised to specific segments radiologically and bronchoscopically. The right lung has 10 segments; the left has 8–10, depending on whether the apical and posterior (B1+2) and anterior and medial basal (B7+8) segments are counted separately.

Location

Throughout both lungs.

Parts & subdivisions

  1. Right superior lobe
    1 Apical, 2 Posterior, 3 Anterior.
  2. Right middle lobe
    4 Lateral, 5 Medial.
  3. Right inferior lobe
    6 Superior, 7 Medial basal, 8 Anterior basal, 9 Lateral basal, 10 Posterior basal.
  4. Left superior lobe
    1+2 Apicoposterior, 3 Anterior, 4 Superior lingular, 5 Inferior lingular.
  5. Left inferior lobe
    6 Superior, 7+8 Anteromedial basal, 9 Lateral basal, 10 Posterior basal.

Function

  • Independent units of ventilation and perfusion.
  • Surgical units for resection.

Clinical significance

Segmentectomy

Small peripheral lung cancers and localised bronchiectasis can be removed by anatomical segmentectomy, dissecting along the intersegmental veins.

Postural drainage

Physiotherapy positions patients so that each affected segmental bronchus points downwards, draining secretions in bronchiectasis and cystic fibrosis.

Mnemonics

Right lung segments

"A Pig Ate Lots of Mice; Super Mice Are Like Pigs" — Apical, Posterior, Anterior (upper); Lateral, Medial (middle); Superior, Medial basal, Anterior basal, Lateral basal, Posterior basal (lower).

Compiled from standard anatomy and physiology references — see the Respiratory System sources. For education only; not medical advice.