[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Chest](https://durgical.com/en/anatomy/region/chest/) › Segmental bronchi [Respiratory system](https://durgical.com/en/anatomy/system/respiratory-system/) · [Chest](https://durgical.com/en/anatomy/region/chest/) # Segmental bronchi The segmental bronchi are the airways that carry air to each lung segment; doctors number them to find their way during bronchoscopy. Official name: Segmental bronchus [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=thorax&select=segmental_bronchi&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The branches to each bronchopulmonary segment, numbered B1 to B10. ## What it does Carry air to each segment; bronchoscopists navigate by these numbers. ## Key points - Right lung, B1 to B10: upper lobe apical, posterior, anterior; middle lobe lateral, medial; lower lobe superior, then medial, anterior, lateral and posterior basal - The left lung often has 8 or 9 segmental bronchi because apical and posterior (upper lobe) and anterior and medial basal (lower lobe) share a trunk - Aspiration by position: lying on the back, posterior segment of the upper lobe and superior segment of the lower lobe; upright, the basal segments of the [right lower lobe](https://durgical.com/en/anatomy/inferior-lobe-of-right-lung/) ## Key facts **Where** Tertiary bronchi numbered B1–B10: 10 on right, 8–10 on left **Blood supply** Bronchial arteries (left from [thoracic aorta](https://durgical.com/en/anatomy/thoracic-aorta/); right usually from 3rd right posterior intercostal artery) **Nerve** Pulmonary plexus: vagus (bronchoconstriction, secretion); upper thoracic sympathetic (bronchodilation) **Function** Each aerates one bronchopulmonary segment; landmarks for bronchoscopy and segmentectomy ## Relations **Course** Each enters the centre of its bronchopulmonary segment with the segmental branch of the pulmonary artery alongside, then divides into subsegmental bronchi and bronchioles; the cartilage is in irregular plates, not rings ## How to find it Found at bronchoscopy, where each opening is named by its number. Postural drainage places the target segmental bronchus so that gravity carries secretions toward the [trachea](https://durgical.com/en/anatomy/trachea/), which is why the segment map matters in [chest](https://durgical.com/en/anatomy/region/chest/) physiotherapy. ## On imaging On thin-section CT each segmental bronchus runs beside its artery, both of about the same calibre; a bronchus clearly wider than its artery (signet ring sign) means bronchiectasis. Segmental consolidation or infarction is wedge-shaped, with its apex toward the hilum. ## Common problems - Narrowing after a long time with a breathing tube. - Inhaled objects, especially in children. ## How it is diagnosed CT, bronchoscopy. ## Treatment - Bronchoscopy to remove objects; stents or surgery for narrowings. ## Clinical notes - Segmentectomy removes one bronchopulmonary segment with its own bronchus and artery, sparing lung in small peripheral tumours or when lung reserve is low - Lung abscess after aspiration typically sits in the posterior segment of the [right upper lobe](https://durgical.com/en/anatomy/superior-lobe-of-right-lung/) or the superior segment of the right lower lobe - Post-tuberculous bronchiectasis favours the apical and posterior segments of the upper lobes, a pattern seen often where tuberculosis is still common, as in Colombia ## Development By about week 7 the lobar buds have branched into tertiary (segmental) buds, ten on the right and eight to ten on the left; each one, with the mesenchyme around it, becomes a bronchopulmonary segment. Branching then continues well beyond this level until the respiratory bronchioles form. ## Memory aid Right lung in order, B1 to B10: A P A, L M, S M A L P (Apical, Posterior, Anterior; Lateral, Medial; Superior, Medial, Anterior, Lateral, Posterior basal). ## Related conditions - [Hydrocarbon ingestion and aspiration](https://durgical.com/en/conditions/hydrocarbon-ingestion-and-aspiration/) - [Aspergillosis](https://durgical.com/en/conditions/aspergillosis/) - [Bronchiolitis (RSV)](https://durgical.com/en/conditions/bronchiolitis/) - [Meconium aspiration syndrome](https://durgical.com/en/conditions/meconium-aspiration-syndrome/) - [Bronchopulmonary dysplasia](https://durgical.com/en/conditions/bronchopulmonary-dysplasia/) - [Cystic fibrosis](https://durgical.com/en/conditions/cystic-fibrosis/) - [Hypersensitivity pneumonitis](https://durgical.com/en/conditions/hypersensitivity-pneumonitis/) - [Allergic bronchopulmonary aspergillosis (ABPA)](https://durgical.com/en/conditions/allergic-bronchopulmonary-aspergillosis/) - [Asthma](https://durgical.com/en/conditions/asthma/) - [Chronic obstructive pulmonary disease (COPD)](https://durgical.com/en/conditions/chronic-obstructive-pulmonary-disease/) - [Bronchiectasis](https://durgical.com/en/conditions/bronchiectasis/) ## Test yourself Think of the answer, then tap the question to see it. ## How are the segmental bronchi of the right lung numbered from B1 to B10? Upper lobe apical, posterior, anterior; middle lobe lateral, medial; lower lobe superior, then medial, anterior, lateral and posterior basal. ## What is the signet ring sign on thin-section CT of a segmental bronchus? A bronchus clearly wider than its accompanying artery; it means bronchiectasis. ## Which segments do post-tuberculous bronchiectasis favour? The apical and posterior segments of the upper lobes. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/segmental-bronchus/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** bronchus segmentalis TA2 3230 **Official Spanish (DeCS)** Bronquios segmentarios DeCS D001980 **English (TA2)** Segmental bronchus **Also called** tertiary bronchus ## Related - [Lobar bronchi](https://durgical.com/en/anatomy/lobar-bronchus/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=2010); [Anatomy, Thorax, Tracheobronchial Tree](https://www.ncbi.nlm.nih.gov/books/NBK556044/); [Anatomy, Thorax, Bronchial](https://www.ncbi.nlm.nih.gov/books/NBK537353/); [22.7 Embryonic Development of the Respiratory System](https://openstax.org/books/anatomy-and-physiology-2e/pages/22-7-embryonic-development-of-the-respiratory-system) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/segmental-bronchus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/segmental-bronchus/