Carina-the trachea (windpipe) divides into two main bronchi (also mainstem bronchi), the left and the right, at the level of the sternal angle at the anatomical point known as the carina. the right main bronchus is wider, shorter, and more vertical than the left main bronchus. the right main bronchus subdivides into three lobar bronchi, while the left main bronchus divides into two. the lobar bronchi divide into tertiary bronchi, also known as segmentalinic bronchi, each of which supplies a bronchopulmonary segment. a bronchopulmonary segment is a division of a lung separated from the rest of the lung by a connective tissue septum
