Anatomy and variations of the carina and its cartilaginous makeup: a cadaveric study

The carina, located at the bifurcation of the trachea, has been regarded as a part of the trachea. Although clinically useful as an anatomical landmark, studies of its detailed morphology are lacking in the literature.

The distal trachea and left and right main bronchi were harvested from 32 cadavers and the carina studied using microsurgical dissection, endoscopy, micro-CT, and histology.

The right bronchial cartilages were most commonly involved in forming the carina (72.41%), and the left bronchial cartilages were the second most commonly involved (37.93%). The carinal cartilages were slightly deviated to the left of midline in 4.37%. Micro-CT clearly identified the contributions to the carinal cartilages.

Although the carina has been regarded as a part of the distal trachea, the present study found that most of the carinal cartilages were composed of the most inferior tracheal ring or bronchial cartilage(s). The right main bronchial cartilage was the most common contributor, and the left main bronchus was the second most common contributor. Additional knowledge of this structure can benefit patient care.