Which of the following statements about esophageal anatomy is true?

A. The arterial blood supply of the mid-esophagus arises primarily from an ascending branch of the left gastric artery and a descending branch of the thyrocervical trunk.
B. The esophagus is normally narrowest where it passes through the diaphragm.
C. Lymphatics of the mid-esophagus drain both cranially to the jugular chain and caudally to the cisterna chyli.
D. Striated muscle extends to the distal third of the esophagus.
E. The Z-line marks the lower esophageal sphincter.

Answer C

The esophagus is a musculocutaneous tube that extends from the cricopharyngeus muscle to the stomach. Measurements from endoscopic procedures offer an important reference. The average distance from the incisor teeth to the cricopharyngeus is 15 cm in men and 14 cm in women. From the incisors to the cardia of the stomach is 38-40 cm in men and 2 cm shorter in women. In men, the length of the esophagus from the cricopharyngeus muscle to the cardia ranges from 23 to 30 cm with an average of 25 cm. In women the range is 20-26 with an average of 23 cm. Three portions are identified: the cervical esophagus, measuring 3-5 cm in length and associated with the C8 through T1 vertebral bodies; the thoracic esophagus, measuring 18-22 cm in length and extending from the T1 to T10 vertebral bodies; and the intra-abdominal esophagus which measures 3-6 cm in length and overlaps the 10th and 11th thoracic vertebral bodies. 

There are three normal anatomic regions of esophageal narrowing (as detected on contrast radiography and endoscopy: (1) the esophageal introitus at the level of the cricopharyngeus muscle; (2) at the left main bronchus and aortic arch; (3) the diaphragmatic hiatus. Of these three areas, the esophagus is narrowest at its inlet. 

The blood supply of the esophagus is regional. In the neck, the arterial blood supply arises primarily from branches of the inferior thyroid artery, a branch of the thyrocervical trunk. The intrathoracic esophagus derives its blood supply from bronchial arteries and small arteries arising directly from the aorta. The distal esophagus is supplied primarily from branches of the left gastric and inferior phrenic arteries. Due to a dense network of fine vessels within the wall of the esophagus, the mobilized esophagus retains an excellent blood supply over a long distance. 

The lymphatic drainage of the esophagus is to regional lymph nodes in the periesophageal connective tissue. Although firm anatomic data is lacking, clinical observation suggests that the lymphatics of the esophagus above the tracheal bifurcation drain cranially to the paratracheal nodes, jugular nodes, and thoracic duct. Lymphatic drainage of the lower esophagus is primarily to celiac nodes and the cysterna chyli. In spite of this, studies of three-field lymphadenectomy specimens show a small but significant incidence of cervical node metastases of lower third esophageal cancers without celiac axis metastasis. 

Microscopically, the esophagus consists of a mucosal layer, a submucosa, a muscular layer, and an adventitial layer but no serosa. The esophageal musculature consists of striated muscle in the upper esophagus with a complete transition to smooth muscle by the carina. The mucosa of the esophagus is stratified squamous epithelium. The transition to columnar epithelium, known as the Z-line, typically occurs at, or just above, the gastroesophageal junction. The anatomic Z-line and the lower esophageal sphincter (determined by manometry) are variably related.

Altorki NK, Skinner DB. Occult cervical nodal metastasis in esophageal cancer: preliminary results of three-field lymphadenectomy. J Thorac Cardiovasc Surg 1997;113:540-4.
The extent of lymphadenectomy for carcinoma of the thoracic esophagus remains debatable. A prospective study was initiated in August 1994 to evaluate the patterns of nodal spread after esophagectomy with three-field lymph node dissection. The hospital mortality rate was 3.3%. Nodal metastases occurred in 73% (22/30) of patients. The most commonly affected nodal groups were the lesser curvature nodes (35%). Cervical nodal metastasis occurred in 10 patients (35%) irrespective of tumor location or T status. The cervical field of dissection was as likely as the mediastinum to be site of nodal disease. These findings should be considered when the operative strategy for esophageal carcinoma is planned.

Isono K, Onoda S, Okuyama K, et al. Recurrence of intrathoracic esophageal cancer. Jpn J Clin Oncol 1985;15:49-60.
We have investigated the site of recurrence after resection of esophageal cancer in a total of 147 cases, which were examined and classified according to the site as follows: lymph nodes, organs, local sites, remnant of the esophagus, and peritoneum. The highest incidence of recurrence was 40% in both lymph nodes and organs. Recurrence was found frequently in the cervical and upper mediastinal lymph nodes. Careful examination should be made in the abdominal para-aortic lymph nodes. As for recurrence in organs, high rates were observed in lung, liver and bone; 70% of the recurrences in these organs were combined with simultaneous metastasis in other organs. In our examination of autopsied cases with local recurrence, the cancer was revealed as a tumor mass covering extensively each side of the posterior mediastinum. At the same time pleural dissemination was frequently observed. In the cases involving recurrence in the remnant esophagus, the disease-free interval was about 18 months--longer than the interval before recurrence in any other site. Peritoneal recurrence appeared in the patients with middle thoracic esophageal cancer. The prognosis following recurrence was extremely bad, with only a few exceptions; the survival period after recurrence was 8 months if it was in the lymph nodes, and an average of 4 months for other types of recurrence. The survival period was only 2 months after peritoneal recurrence.