The œsophagus is a musculo-membranous tube, about 50 to 60 inches (ca.
125 to 150 cm.) in length, which extends from the pharynx to the
stomach. It begins in the median plane above the cricoid cartilage of
the larynx. In its course it shows several changes of direction. At the
level of the fourth cervical vertebra it inclines to the left side of
the trachea, and continues this relation to the level of the third
thoracic vertebra. Here it again gains the dorsal surface of the
trachea, and passing backward, crosses the left bronchus, being here
almost in the median plane. It continues in the mediastinum between the
lungs backward, upward, and a little to the left, to reach the hiatus
œsophageus of the diaphragm. Passing through this it terminates at once
at the cardiac orifice of the stomach, at the level of the fourteenth
thoracic vertebra, a little to the left of the median plane, and about
four or five inches (ca. 10 to 12 cm.) ventral to the vertebral column.
Viewed with reference to the frontal plane, its course is downward and
backward till it enters the thorax and passes upward to gain the dorsal
face of the trachea. For a short distance (_i. e._, to the root of the
lung) its direction is almost horizontal; behind this it passes somewhat
upward to its termination. The =cervical part= of the tube is about four
to six inches (10 to 15 cm.) longer than the =thoracic part=, while the
so-called abdominal part is about an inch (2 to 3 cm.) long.[85]
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