Imaging of spaces of neck and mediastinum by endoscopic ultrasound.

Endoscopic ultrasound (EUS) of the mediastinum was pioneered by gastroenterologists, and it was taken up by pulmonologists when the smaller-diameter endobronchial ultrasound (EBUS) scope was designed after a few years. The pulmonologists' approach remained largely confined to entry from the trachea, but they soon realized that the esophagus was an alternative route of entry by the EBUS scope. The new generations of interventionists are facing the challenge of learning two techniques (EUS and EBUS) from two routes (esophagus and trachea). The International Association for the Study of Lung Cancer (IASLC) proposed a classification of mediastinal lymph nodes at different stations that lie within the boundaries of specific spaces. These interventionists need clear definitions of landmarks and clear techniques to identify the spaces. There are enough descriptions of spaces of the neck and the mediastinum in the literature, yet the topic mentioned above has never been discussed separately. The anatomical structures, landmarks, and boundaries of spaces will be important to interventionists in the near future during performances of endosonography. This article combines the baseline anatomy of the spaces with the actual imaging during EUS.