Definition
The esophageal hiatus is an opening in the muscular diaphragm through which the esophagus passes from the thoracic cavity into the abdominal cavity, allowing the continuation of the gastrointestinal tract into the stomach.
Overview
Located at the level of the tenth thoracic vertebra (T10), the esophageal hiatus is a key component of the diaphragmatic aperture system, which also includes the aortic and caval openings. The hiatus is bounded by the right crus of the diaphragm, a muscular structure that forms a fibrous ring encircling the esophagus. This anatomical configuration facilitates the transmission of peristaltic movements from the esophagus to the stomach while maintaining the integrity of the diaphragmatic seal that separates the thoracic and abdominal compartments. The surrounding musculature, particularly the crural fibers, contributes to the functional lower esophageal sphincter (LES), helping to prevent gastro‑esophageal reflux.
Etymology/Origin
The term combines “esophageal,” derived from the Greek esophagos (ḗsophagos) meaning “to swallow,” referring to the esophagus, and “hiatus,” a Latin word meaning “opening” or “gap.” Together they denote the opening for the esophagus.
Characteristics
- Anatomical Position: Situated posteriorly within the diaphragm at the vertebral level T10.
- Boundaries: Formed primarily by the right crus of the diaphragm; the left crus contributes minimally.
- Dimensions: Typically 2–3 cm in diameter in adults, allowing passage of the esophagus and associated structures such as the vagus nerves and esophageal branches of the left gastric vessels.
- Physiological Role: The surrounding crural fibers augment LES pressure, providing a secondary barrier against reflux.
- Clinical Significance: Enlargement or weakening of the hiatus can lead to hiatal hernia, where part of the stomach protrudes into the thoracic cavity. Surgical repair (e.g., Nissen fundoplication) often involves reinforcement of the hiatus.
- Variations: Congenital anomalies such as a diaphragmatic eventration may alter the shape or size of the hiatus.
Related Topics
- Diaphragm (muscular respiratory partition)
- Lower esophageal sphincter (LES)
- Hiatal hernia
- Crus of the diaphragm (right and left)
- Gastroesophageal reflux disease (GERD)
- Nissen fundoplication (surgical procedure)
- Thoracoabdominal anatomy
- Vagus nerve (cranial nerve X) and its esophageal branches