Sonographic anatomy of the cervical esophagus

Although conventional sonography is used widely for evaluation of the gastroesophageal junction, its use in the cervical esophagus is still limited. The aim of this study was to assess the use of sonography to demonstrate this portion of the esophagus.

The cervical esophagi in 60 cadavers and 435 healthy volunteers were examined sonographically. Among the healthy subjects 182 were scanned with a transducer operating at 7.5 MHz, 183 with a 10.0-MHz transducer, and 70 with a 12.0-MHz transducer. Sonographic layer patterns were compared among the groups. Sonographic and histologic analyses were also performed on 3 cadaveric esophageal specimens to correlate the sonographic appearances with the anatomical findings.

Scans of the cadavers showed that the cervical esophagus lay between the trachea and vertebrae, with its origin at the midline; it gradually moved to the left as it descended toward the trunk. It moved to the right when the cadaver's head was turned to the left and the trachea was pushed gently to the left. Based on these anatomical characteristics, visualization of the cervical esophagus was optimized by scanning from both the left and the right lateral approaches, with manipulation of the trachea as needed. In scans of the 435 healthy subjects, the esophageal wall was shown as 5 layers in 423 (97.2%) and as 7 layers in the remaining 12 (2.8%). The demonstration rate of the 7-layer pattern was significantly higher for subjects scanned at 12.0 MHz than for those scanned at 10.0 and 7.5 MHz (p < 0.01). The layers demonstrated sonographically corresponded to histological structures evident on microscopy.

The left lateral approach is essential to sonography of the cervical esophagus. However, the right wall of the esophagus is best seen from the right. In transverse scans, the cervical esophagus wall usually appears to be composed of 5 layers, although 7 layers can also appear, especially as the transducer frequency is increased.