Chapter 80

The complaints of dysphagia, odynophagia, or ingested foreign body immediately implicate the esophagus. The esophagus also is often the site of pathology in patients presenting with chest pain, upper GI bleeding (see Chapter 78, Upper Gastrointestinal Bleeding), malignancy, and mediastinitis. Many diseases of the esophagus can be evaluated over time in an outpatient setting, but several, such as esophageal foreign body and esophageal perforation, must be addressed emergently.

### Pathophysiology

The esophagus is a muscular tube approximately 20 to 25 cm long. The majority of the esophagus is located in the mediastinum, posterior and slightly lateral to the trachea, with smaller cervical and abdominal components as well, as shown in Figure 80-1. There is an outer longitudinal muscle layer and an inner circular muscle layer. The upper third of the esophagus is made up of striated muscle. From the lower half down, the esophagus is all smooth muscle (including the lower esophageal sphincter). The esophagus is lined with stratified squamous epithelial cells that have no secretory function.

###### Figure 80-1.

Anatomic relations of the esophagus (seen from the left side). The esophagus is about 25 cm (10 in.) long. The distance from the upper incisor teeth to the beginning of the esophagus (cricoid cartilage) is about 15 cm (6 in.); from the upper incisors to the level of the bronchi, 22 to 23 cm (9 in.); and to the cardia, 40 cm (16 in.). Structures contiguous to the esophagus that affect esophageal function are shown.

Two sphincters regulate the passage of material into and out of the esophagus. The upper esophageal sphincter prevents air from entering the esophagus and food from refluxing out of the esophagus into the pharynx. The lower esophageal sphincter regulates the passage of food into the stomach and prevents stomach contents from refluxing into the esophagus. The upper sphincter is composed primarily of the cricopharyngeus muscle. Additional tone is variably provided by the inferior pharyngeal constrictor muscle and the cervical esophagus.1 The upper sphincter has a resting pressure of around 100 mm Hg. The lower sphincter is not discretely identifiable on an anatomic basis. The smooth muscle of the lower 1 to 2 cm of the esophagus, in combination with the skeletal muscle of the diaphragmatic hiatus, functions as the sphincter, with a resting pressure of 25 mm Hg. The pressure within the resting lower sphincter is a major source of esophageal symptoms and is discussed below under Gastroesophageal Reflux Disease.

Three major anatomic constrictions exist within the adult esophagus and are important when there is an esophageal foreign body or food bolus impaction: at the cricopharyngeus muscle (C6), at the level of the aortic arch (T4), and at the gastroesophageal junction (T10 to T11). The pediatric esophagus has two additional areas of constriction: the thoracic inlet (T1) and the tracheal bifurcation (T6). ...

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