THE INFERIOR ESOPHAGEAL SPHINCTER—ANATOMIC, ROENTGENOLOGIC AND MANOMETRIC CORRELATION, CONTRADICTIONS, AND TERMINOLOGY

1. The term "inferior esophageal sphincter" for a contractile ring at the end of the tubular esophagus was introduced into the radiologic literature as a result of the dissections and descriptions of Lerche. This correlation was based on observations in patients with small sliding hernias rather than on appearances in normal individuals. Subsequently, it was demonstrated that the normal antireflux mechanism is not a ringlike segment above the diaphragm but a zone about 4 cm. in length which straddles the hiatus. The term inferior esophageal sphincter is currently accepted for this region or zone of resting high pressure and therefore should not be used for a discrete ring at the end of the tubular esophagus.

2. There are two potential lower esophageal rings—one functional and the other static. The functional ring is located at the end of the tubular esophagus. The static ring is located more distally adjacent to the squamo-columnar mucosal junction.

3. A prominent or persistent contractile ring at the end of the tubular esophagus is an abnormal finding and frequently a manifestation of a small hernia. It is also a common feature of a variety of functional abnormalities. In the presence of herniation, it may serve as a rather ineffective antireflux mechanism but may also become "spastic" and cause periodic dysphagia.

4. The terms phrenic ampulla, submerged segment, cardia, cardiac canal, cardiac antrum, A and B levels, and vestibule are discussed.

5. Inconsistencies in the use of the term "sphincter" both roentgenologically and manometrically are pointed out.

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