Esophagus and Mediastinum

Abstract

The esophagus is, from an endosonographer’s perspective, the window into the mediastinum, and it makes sense to consider both anatomic regions together. A good understanding of mediastinal anatomy is a prerequisite for competent image interpretation. After a basic review of cross-sectional and traditional anatomy, the endosonographer should approach mediastinal anatomy from the perspective of the ultrasound transducer in the esophagus. Numerous resources on the Internet allow familiarization of 3-dimensional anatomy of the mediastinum from every possible angle and vantage point, allowing structures and layers to be peeled away and added as desired (see Box 2.1). The number of possible cross sections that can be achieved with linear and radial endosonography probes vastly exceed those that can be reasonably expected to be represented in image collections even if they are dedicated to the topic (e.g., in an endoscopic ultrasound [EUS] anatomy atlas), although these collections are certainly helpful. Therefore, the endosonographer should make a point of identifying mediastinal structures every time an upper EUS exam is being conducted until such time when the mediastinum becomes a “second home.” There is an amusing little book called Flatland that can help condition the brain on how 3-dimensional reality might be reflected in a 2-dimensional plane (see Box 2.1).