THE (SOPHAGUS 409 
Vessels and Nerves.—The arteries are derived from the common carotid, 
external carotid, and external maxillary arteries. The lymph vessels pass to the 
pharyngeal and anterior cervical lymph glands. The nerves are derived from the 
trigeminus, glosso-pharyngeus, and vagus. 
THE CSOPHAGUS 
The cesophagus 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. In 
its course it shows several changes of direction. It begins in the median plane above 
the anterior border of the cricoid cartilage of the larynx. At the fourth cervical 
vertebra it has passed to the left side of the trachea, and continues this relation 
as far as the third thoracie vertebra. Here it again gains the dorsal surface of the 
trachea, and, passing backward, crosses the aortic arch, by which it is pushed over 
to the right of the median plane. It continues in the mediastinum between the 
lungs, backward and a little dorsally, inclining gradually to the left, and reaches 
the hiatus cesophageus of the diaphragm. Passing through this it terminates at 
once at the cardiac orifice of the stomach, a little to the left of the median plane, 
and about four or five inches (ca. 10 to 12 cm.) ventral to the vertebral end of the 
fourteenth rib.t 
Viewed with reference to the horizontal plane, its course is downward and 
backward till it enters the thorax and passes upward to gain the dorsal face of 
the trachea. Then for a short distance (7. e., to the root of the lung) its direction is 
almost horizontal; behind this it passes somewhat upward to its termination. 
The cervical part (Pars cervicalis) of the tube is about four to six inches (10 to 15 
em.) longer than the thoracic part (Pars thoracalis), while the so-called abdominal 
part (Pars abdominalis) is about an inch (2 to 3 em.) long.” 
The principal relations of the cesophagus at its origin are: to the cricoid 
cartilage and dorsal crico-arytenoid muscles ventrally; to the guttural pouches 
and the ventral straight muscles dorsally; and to the carotid arteries laterally. 
In the middle of the neck the relations are: to the left longus colli muscle dorsally; 
to the trachea medially; to the left carotid artery, vagus, sympathetic, and recurrent 
nerves laterally. Near the thoracic inlet the cesophagus is usually in contact 
with the left jugular vein for a short distance. At its entrance into the thorax 
it has the trachea on its medial side; the first rib, the roots of the brachial plexus 
of nerves, and the left posterior cervical ganglion laterally. After gaining the 
dorsal surface of the trachea, it has the aorta on its left and the vena azygos and 
right vagus nerve on its right side. In its course through the posterior medias- 
tinum the cesophageal trunks of the vagus nerves lie above and below it, and the 
esophageal artery is dorsal to it. 
Structure.—The wall is composed of four coats: (1) A fibrous sheath termed 
the tunica adventitia; (2) the muscular coat; (3) a submucous layer; (4) the 
mucous membrane. The muscular coat is of the striped variety as far as the base 
of the heart, where it rapidly changes to the unstriped type. In addition to this 
change, the muscular coat becomes much thicker and firmer, while the lumen is 
diminished. Except at each end of the tube the muscular coat consists chiefly of 
a 
* The distance between the terminal part of the cesophagus and the vertebra varies. In 
formalin-hardened subjects it is most commonly as given above, but in soft specimens or in those 
which have been frozen without previous fixation it is usually nearer the spine. 
* Careful observations (especially on frozen subjects and those in which the organs haye been 
hardened in situ) show that there is no abdominal part of the cesophagus in the strict sense of the 
term. The stomach here lies directly on the diaphragm, so that the last inch or so of the cesopha- 
gus is placed obliquely in the hiatus cesophageus, and is covered on the right and ventrally by the 
pleura, but not by peritoneum. In soft subjects the weight of the stomach, or traction on it, draws 
part of the cesophagus into the abdomen, inclosed in a collar of peritoneum. 
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