Middle lobar bronchus
Bronchus lobaris medius
The forward-running branch of the right intermediate bronchus that supplies the middle lobe of the right lung.
At a glance
- English
- Middle lobar bronchus
- Latin (TA2)
- Bronchus lobaris medius
- System
- Respiratory
- Region
- Thorax
- Side
- Right side
About the middle lobar bronchus
The middle lobar bronchus exists only in the right lung, which alone has a middle lobe. It arises from the front wall of the intermediate bronchus inside the hilum, at almost the same level as the superior segmental branch of the lower lobe arises from the back wall. From there it runs forwards, downwards and slightly outwards for one to two centimetres before splitting into two segmental bronchi, the lateral and the medial, for the two segments of the middle lobe.
The middle lobe is the wedge of lung bounded by the horizontal fissure above and the oblique fissure below and behind. It lies against the front of the chest wall and the right border of the heart, so its bronchus points forwards towards the sternum rather than downwards like the lower-lobe airways. Its counterpart on the left is the lingular bronchus of the upper lobe.
The wall follows the bronchial pattern of cartilage plates, smooth muscle and ciliated mucosa. What makes it different is its shape: it is long and narrow compared with its neighbours, it leaves the parent airway at a sharp angle, and it is ringed by lymph nodes at its origin.
These features explain the middle lobe syndrome, in which the lobe repeatedly collapses or becomes infected. Swollen lymph nodes, mucus or a small growth can easily block the narrow bronchus, and the lobe gets little collateral ventilation from its neighbours because its fissures are usually complete. On a frontal chest X-ray disease here blurs the right heart border, a useful sign for locating it.
Function and supply
- Begins at
- The anterior wall of the intermediate bronchus within the hilum of the right lung.
- Ends at
- Divides into the lateral and medial segmental bronchi of the middle lobe.
- Function
- Conducts air to and from the middle lobe of the right lung.
- Nerve supply
- Pulmonary plexus (vagal and sympathetic fibres).
- Blood supply
- Right bronchial artery.
Anthromica
See the middle lobar 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.
