The ESOPHAGUS

The esophagus, whether by reason of its deeply placed anatomical location or the scarcity of exact knowledge concerning its physiological activity, has been until recent years somewhat of an organ of mystery. Improvements in endoscopic methods of examination, the development of new surgical techniques, the advent of the antibiotic drugs, and the physiological approach to the understanding of normal and abnormal activity with the aid of intraluminal pressure studies and cineroentgenography, all have been of great importance in creating a better understanding of the function, both normal and abnormal, and the disease entities of this important structure.

While the organ is capable of marked distensibility as evidenced by the enormous boluses some people are able to swallow comfortably, it is also noted for its friability; its walls are thin and may disrupt easily, as has been demonstrated during esophagoscopy or the passage of a bougie. The absence of any pleural or peritoneal covering makes it difficult for the surgeon to place sutures in its wall. For this reason surgery of the esophagus demands an exceptionally meticulous technique.

For all practical purposes, the length of the esophagus and its various segments in the living subject is measured in terms of the distance from the upper incisor teeth as determined by esophagoscopy. Von Hacker’s original measurements are still accurate and apply clinically. In the average male patient, the distance from the incisor teeth to the cardia is 40 cm; from the incisor teeth to the upper end or mouth of the organ, the average distance is 15 cm; and from the incisor teeth to the level of the arch of the aorta, the distance is 26 cm. In the female, the organ is somewhat shorter. The general habitus of the patient has, in my experience, influenced the length of the organ. In tall individuals with long chests, the esophagus may reach a length of 42 cm to 45 cm.

Of interest to the roentgenologist, esophagoscopist, and the surgeon are the two major sites of constriction of the esophagus. The upper one is the cricopharyn – geal constriction caused by the cricopharyngeus muscle and the cricoid cartilage. This narrowest segment of the organ is treated with great respect by the endoscopists because of the frequency of instrumental perforation at this site. The other major constriction is located at the point where the esophagus passes through the hiatus in the diaphragm, the diaphragmatic pinchcock. Two lesser sites of constriction are caused by the indentation of the aortic arch and the left main bronchus, just below the former. These are of interest mainly to the roentgenologist.

The blood supply of the esophagus is of considerable importance to the surgeon, especially in the conduct of the operation of esophagectomy for carcinoma. In the main, the arterial supply is segmental in distribution with rather tenuous anastomoses between these segments. The cervical segment is supplied principally by branches of the inferior thyroid artery, with some additional nourishment coming from branches of the pharyngeal arteries and the esophageal artery of Luschka, a small branch from the subclavian artery. The supra-aortic thoracic segment is supplied by the lower end of the artery of Luschka and descending branches from the inferior thyroid artery. The midthoracic segment of esophagus is supplied by branches from the bronchial artery and occasionally by a small vessel originating from the undersurface of the aortic arch. In my experience, this latter is a rare source of blood supply. Anastomoses circumscribe the organ and connect the segmentally distributed vessels.

The lower thoracic segment is supplied by three or four branches coming directly from the descending aorta. The abdominal portion of the esophagus receives its blood supply from branches of the left gastric artery and the left inferior phrenic artery. These facts are important in the performance of total gastrectomy with esophagojejunal anastomosis. The integrity of the terminal esophagus must be assured before this type of anastomosis can be successfully consummated.

The venous drainage of the esophagus is mainly through the azygos system into the superior vena cava. This is of importance with respect to the interpretation of the azygogram, a recently developed roentgenographic examination which may be of considerable aid in determining operability of carcinomas in the middle third of the thoracic esophagus.

The lymphatic drainage of the esophagus is naturally of great importance in relation to cancer of the organ. One must remember that the esophagus is richly supplied with lymph channels, especially in the submucosa, which may become permeated by cancer cells, not obvious to the surgeon at the time of operation. This important anatomical fact must be constantly kept in mind while operating for malignant tumors. In general, the direction of lymphatic flow in the upper half of the esophagus is upward toward the neck, while the flow in the lower half is downward. One should not assume, however, that these directions of flow follow a regular pattern. As a matter of fact, in my experience, the exceptions are more common than what might be considered the regular or anatomical direction of lymphatic flow. More often than not, the nodes along the left gastric vessels will be found involved when the primary site is located in the middle third of the esophagus. This occurs in approximately 50 percent.

In general, lymph node metastases occur in the area of location of the primary tumor, i. e., the internal jugular nodes, the paratracheal, the peribronchial, and periesophageal nodes in the chest, and the paracardial nodes and those along the left gastric vessels below the diaphragm. An appreciation of the lymphatic drainage of the esophagus and the directions which lymphatic flow may take is of great importance to the surgeon who undertakes an operation for cancer of the esophagus.

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