Complex sentence: The right main bronchus (or right primary bronchus, or right principal bronchus), wider, shorter, and more vertical in direction than the left, is about 2.5 cm. long, and enters the right lung nearly opposite the fifth thoracic vertebra.
Split into simpler sentences: The right main bronchus (or right primary bronchus, or right principal bronchus) is a bronchus of the respiratory system. It is about 2.5 cm. long, and enters the right lung nearly opposite the fifth thoracic vertebra.