Lobar bronchus to right cranial lobe

The lobar bronchus for the right cranial lobe is the secondary bronchus that provides ventilation to the right cranial lung lobe. Its anatomical origin is a major distinguishing characteristic between species.

In certain species such as ruminants (cattle, sheep), this bronchus, then called the tracheal bronchus, branches directly from the right side of the trachea, upstream from the main tracheal bifurcation.

In other species such as the cat, dog and horse, it originates more classically from the right main bronchus, just after the tracheal bifurcation.

This variation is of critical clinical importance, particularly in endoscopy, as the visualization of its opening before the carina is a key anatomical landmark in dogs and ruminants. Once emitted, it divides into segmental and subsegmental branches to distribute air throughout the parenchyma of the right cranial lobe.