Tracheal bifurcation - Bifurcatio tracheae
The carina of trachea is a cartilaginous ridge within the trachea that runs antero-posteriorly between the two primary bronchi at the site of the tracheal bifurcation at the lower end of the trachea (usually at the level of the 5th thoracic vertebra, which is in line with the angle of Louis, but may raise or descend up to two vertebrae higher or lower with breathing). This ridge lies to the left of the midline.
This definition incorporates text from the wikipedia website - Wikipedia: The free encyclopedia. (2004, July 22). FL: Wikimedia Foundation, Inc. Retrieved August 10, 2004, from http://www.wikipedia.org