primary bronchus

pri·mar·y bron·chus

the main bronchus arising at the tracheal bifurcation and extending into the developing lung of the embryo.

primary bronchus

one of the two main air passages that branch from the trachea and convey air to the lungs as part of the respiratory system. The right primary bronchus enters the right lung nearly opposite the fifth thoracic vertebra. The left primary bronchus divides into bronchi for the superior and anterior lobes of the lung. The bronchi, like the trachea, are composed of rings of hyaline cartilage, fibrous tissue, mucous membrane, and glands. The right primary bronchus has a more direct extension of the trachea than the left. Hence foreign objects entering the trachea usually drop into the right bronchus rather than the left. See also bronchial tree.

mainstem bronchus

Either of two (right and left) bronchi which continue from the trachea and in turn give rise to lobar (secondary) bronchi.
References in periodicals archive ?
The question posed was whether this mass could be ascribed to metastatic supraglottic carcinoma or if it was indeed a metachronous primary bronchus carcinoma, as the treatment of these two malignancies differs significantly.
Videothoracoscopic echinococcectomy was conducted by one lung ventilation with intubation of the right or left primary bronchus.
Bronchi: a single tube branching off from the trachea called the primary bronchus serves each lung.