Intermediate bronchus
Bronchus intermedius
The short stretch of the right main bronchus between the upper-lobe branch and its division into middle and lower lobar bronchi.
At a glance
- English
- Intermediate bronchus
- Latin (TA2)
- Bronchus intermedius
- System
- Respiratory
- Region
- Thorax
- Side
- Right side
About the intermediate bronchus
The intermediate bronchus, or bronchus intermedius, exists only on the right. Soon after the right main bronchus leaves the carina it gives off the right superior lobar bronchus to the upper lobe. What remains continues downwards and slightly outwards in the same line as the main bronchus, and this continuation is the intermediate bronchus. It is a few centimetres long, typically around two and a half, and ends inside the hilum by splitting into the middle lobar bronchus, which runs forwards, and the inferior lobar bronchus, which carries on downwards and back.
Its position below the right pulmonary artery makes it the start of the hyparterial airways of the right lung. The artery, having crossed in front of the main bronchus, comes to lie in front of and then lateral to the intermediate bronchus as it descends into the lung. Behind it lies the posterior wall of the bronchus, which is in contact with lung tissue of the lower lobe and is seen as a thin stripe on a lateral chest X-ray.
The wall has the same structure as the main bronchus: plates and rings of hyaline cartilage, smooth muscle, glands and a ciliated lining with goblet cells. It conducts air and takes no part in gas exchange.
Several clinical points arise. Because the right side forms a straight path from the trachea, inhaled foreign bodies often lodge in the intermediate bronchus and can block both the middle and lower lobes at once. Thickening of its posterior wall on X-ray can be an early sign of fluid, tumour or enlarged lymph nodes. A rare accessory branch, the cardiac bronchus, may arise from its medial wall and end blindly or supply a small piece of lung.
Function and supply
- Begins at
- The right main bronchus, just below the origin of the right superior lobar bronchus.
- Ends at
- Divides within the hilum of the right lung into the middle and inferior lobar bronchi.
- Function
- Conducts air to and from the middle and lower lobes of the right lung.
- Nerve supply
- Pulmonary plexus (vagal and sympathetic fibres).
- Blood supply
- Right bronchial artery; venous blood to the azygos vein and pulmonary veins.
Anthromica
See the intermediate bronchus where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
