The Trachea.
—The trachea or windpipe is a cartilaginous elastic, cylindrical tube, flattened posteriorly. It extends from the lower part of the larynx, on a level with the sixth cervical vertebra to opposite the body of the fourth dorsal, where it divides into two bronchi, one for each lung.
Fig. 17—The cartilages of the larynx; the trachea and bronchi. (Gray)
The trachea is in the median line of the body. It measures about four and one-half inches in length. The diameter is from three quarters to one inch, being always greater in the male than in the female.
The trachea is composed of imperfect cartilage rings, not coming quite together in the back.
The artery that supplies the trachea is the inferior thyroid artery.
The vein that withdraws the blood is the inferior thyroid vein.
The Right Bronchus.—The right bronchus is shorter, and wider than the left bronchus. It is about one inch in length. It enters the lung opposite the fifth dorsal vertebra.