Overview

Length≈2.5 cm

Angle from vertical≈25°

The right main bronchus diverges from the vertical by only ≈25° (vs ≈45° on the left), is wider and is about half the length of the left. Within ≈2 cm of the carina, before entering the hilum, it gives off the right superior lobe bronchus, which arises above the right pulmonary artery — the eparterial bronchus. The continuation, the bronchus intermedius, passes below the artery and divides into the middle and inferior lobe bronchi.

The arch of the azygos vein hooks over it from behind to reach the SVC, and the right pulmonary artery lies at first below and then in front of it.

Location: From the carina to the right hilum, entering the lung at ≈T5.

Parts & subdivisions

Right superior lobe bronchus
Eparterial; arises outside the hilum close to the carina.
Bronchus intermedius
Short segment between the upper lobe bronchus and the origin of the middle lobe bronchus.

Anatomy

Relations: Superiorly/posteriorly: arch of the azygos vein; anteriorly: right pulmonary artery, SVC and ascending aorta; posteriorly: right vagus nerve and oesophagus (medially).

Function

Conducts air to the right lung (≈55% of total ventilation).

Clinical significance

Aspiration

Inhaled foreign bodies and gastric contents enter the right lung more often. Upright: posterior basal segment of the right lower lobe. Supine: superior segment of the right lower lobe or posterior segment of the right upper lobe. Right-sided: lateral recumbent position favours the right middle and upper lobe posterior segments. Aspiration pneumonia and lung abscess cluster in these segments (alcohol use, reduced consciousness, dysphagia).

Endobronchial intubation

An over-advanced tracheal tube usually enters the right main bronchus, causing collapse of the left lung and possibly the right upper lobe; auscultate both sides and confirm with radiography.

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