is a muscular tube measuring about 25 cm (40 cm from the incisor teeth) extending from the pharynx at the cricoid cartilage to the cardia of the stomach. It pierces the left crus of the diaphragm and has an intraabdominal portion of about 1.5 to 2.5 cm in length.

consists of a nonkeratinizing squamous epithelium, lamina propria extending into the basal layer as rete pegs, and muscularis mucosa, which is sparse and thin in the upper portion but thicker near the gastroesophageal junction.

contains mucous glands and an extensive lymphatic plexus in a connective tissue network.

Between the submucosa and muscularis propria are the cell bodies of secondary neurons forming the Auerbach’s plexus.

The muscularis propria, the main muscle layers of the esophagus, is composed of inner circular and outer longitudinal coats. In the upper part, these are striated. There is a gradual change to smooth muscle in the middle. In the lower third of the esophagus, both of these coats are entirely composed of smooth muscle.

Between the muscle layers, the myenteric plexus contains the cell bodies of other secondary neurons.

The esophagus does not have a serosal layer.

The distal 3 to 4 cm of the esophagus constitutes a zone of increased resting pressure in an asymmetric fashion. This area, called the lower esophageal sphincter (LES), behaves both physiologically and pharmacologically as a distinct entity from the esophageal smooth muscle immediately adjacent to it. Basal LES pressure is normally 10 to 25 mmHg higher than intragastric pressure and drops promptly (within 1-2 seconds) with swallowing. The LES control remains poorly understood but is thought to involve the complex interaction of neural, hormonal, and myogenic activities.

begins when a liquid or solid bolus is propelled to the back of the mouth into the pharynx by the tongue. The upper esophageal sphincter (UES), the cricopharyngeus, which is just below the pharynx, relaxes, allowing the bolus to pass into the upper esophagus. In response to swallowing, an orderly, progressive contraction of the esophageal body occurs (primary peristalsis), propelling the bolus down the esophagus. When the esophagus is distended by a bolus (i.e., with regurgitation), secondary peristaltic contractions are initiated. The LES relaxes as the bolus reaches the lower esophagus, allowing passage of the food into the stomach.

are initiated by the voluntary act of swallowing, controlled by the swallowing center in the brainstem and the fifth, seventh, ninth, tenth, eleventh, and twelfth cranial nerves. These nerves coordinate the movement of the bolus to the hypopharynx,
closure of the epiglottis, relaxation of the UES, and contraction of the striated muscle of the upper esophagus. The sequential nature of this function is due to progressive activation of nerve fibers carried in the vagus nerve controlled through a central mechanism.

is regulated by activation of neurons located in the myenteric plexus with cholinergic neural transmission. The vagi innervate the upper esophagus in its striated muscle portion only. If the vagi are cut below the level of mid esophagus, peristalsis in the lower half of the esophagus and the function of the LES remain intact.

is difficulty in swallowing. Clinically, it includes the inability to initiate swallowing and/or the sensation that the swallowed solids or liquids stick in the esophagus.

refers to pain with swallowing. In some disorders, odynophagia may accompany dysphagia.

describes the sensation of the presence of “a lump in the throat” that is relieved momentarily by swallowing.

These patients usually cough and expel the ingested food through their mouth and nose or aspirate when they attempt to swallow. Their symptoms are worse with liquids than with solids. They may have a “wet” voice quality, reduced cough, upper airway congestion, and aspiration pneumonitis.

a. Central nervous system conditions. Cerebral vascular accidents (bulbar or pseudobulbar palsy), multiple sclerosis, amyotrophic lateral sclerosis, Wilson’s disease, Parkinson’s disease, Friedreich’s ataxia, tabes dorsalis, brainstem tumors, paraneoplastic disorders, reaction to drugs or toxins, other congenital and degenerative disorders of the central nervous system.

b. Peripheral nervous system conditions. Poliomyelitis (bulbar), diphtheria, rabies, botulism, diabetes mellitus, demyelinating diseases, Guillain-Barré syndrome.

c. Disorders of the myoneural junction. Myasthenia gravis, Eaton-Lambert syndrome.

d. Muscular disorders. Dermatomyositis, muscular dystrophies, myotonic disorders, congenital myopathies, metabolic myopathies (thyrotoxicosis, hypothyroidism, hyperthyroidism, steroid myopathy), collagen vascular diseases, amyloidosis.

e. Toxins. Tetanus, botulism, tic paralysis, arsenic, lead, mercury poisoning.

f. Local structural lesions. Conditions involving the mouth, pharynx, and hypopharynx.

i. Infection or inflammation. Abscess; tuberculosis; syphilis; viral, bacterial, and fungal infections; Lyme disease; diphtheria; rabies.

ii. Space-occupying lesions. Neoplasms, congenital webs, Plummer-Vinson syndrome.

iii. Extrinsic compression. Cervical spine spurs, lymphadenopathy, thyromegaly, Zenker’s diverticulum.

iv. Trauma. Surgical repair, foreign body ingestion, caustic injury.

g. Motility disorders of the upper esophageal sphincter. Hypertensive UES, hypotensive UES with esophagopharyngeal regurgitation, abnormal
UES relaxation (incomplete relaxation: cricopharyngeal achalasia, premature closure, delayed relaxation).

are usually caused by a discrete lesion such as a neoplasm, stricture, or extrinsic compression that interferes with the transport of the swallowed bolus. Initially, dysphagia is noted with solid foods. However, as the lumen narrows with enlarging lesions, passage of liquids also becomes impaired.

a. Tumors (see also Chapter 23)

i. Squamous carcinoma accounts for approximately one third of all esophageal cancers. Excessive alcohol intake and cigarette smoking seem to increase the risk. Other predisposing factors include head and neck cancer, Plummer-Vinson syndrome (anemia and esophageal web), tylosis, achalasia, and lye stricture.

ii. Adenocarcinoma of the esophagus constitutes about two thirds of esophageal cancers. It is thought to arise from extension of gastric cardia carcinoma, from the esophageal glands or, more commonly, from the columnar metaplasia of the esophagus (Barrett’s epithelium).

iii. Kaposi’s sarcoma, lymphoma, melanoma, and metastatic tumors from the lungs, pancreas, breasts, and other structures may also involve the esophagus.

iv. Benign tumors of the esophagus are rare and account for less than 10% of esophageal tumors. These tumors most commonly arise from neuromesenchymal elements. Leiomyomas that arise from esophageal smooth muscle are the most common. These intramural lesions are covered by normal squamous epithelium of the esophagus. They protrude into the lumen, eventually causing narrowing of the passage. Other lesions such as fibroadenomas, though rare, may become very long and large and may cause obstruction.

i. Peptic strictures. Most esophageal strictures are found in the distal or mid esophagus and are the result of chronic inflammation caused by gastroesophageal reflux. Peptic strictures are usually benign, but those associated with Barrett’s epithelium may be malignant.

ii. Burns caused by ingestion of corrosive substances (e.g., strong alkali and acids) may result in esophageal strictures in single or multiple locations of the esophagus.

iii. Some drugs in tablet form may lodge in a segment of the esophagus and cause local inflammation, ulceration, and stricture.

iv. Foreign bodies (e.g., coins or button batteries) may be swallowed and cause obstruction or injury of the esophagus.

c. Rings and webs are usually thin, circumferential mucosal shelves that protrude into the esophageal lumen and cause intermittent dysphagia, especially to solids. Webs occur in the upper esophagus and may be associated with iron-deficiency anemia (Plummer-Vinson syndrome).

Rings (Schatzki) are most often found at the gastroesophageal junction. Schatzki’s rings seem to be related to chronic gastroesophageal reflux. Most of these contain only mucosal elements; however, thicker ones may also contain a thickened muscle layer.

d. Eosinophilic esophagitis is an inflammatory condition of the esophagus anatomically characterized by the presence of multiple concentric firm rings
throughout the entire length of the esophagus. It is also referred to as corrugated esophagus, ringed esophagus, corrugated ringed esophagus, and congenital esophageal stenosis occurring in children and young adults, especially males.