title: Anatomic-manometric correlation of the upper esophageal sphincter: a concurrent US and manometry study.
abstract: BACKGROUND
  The pharyngoesophageal segment commonly referred to as the upper esophageal sphincter (UES) generates a high-pressure zone (HPZ) between the pharynx and the esophagus. However, the exact anatomical components of the UES-HPZ remain incompletely determined.
  
  
  OBJECTIVE
  To systematically define the US signature of various components of the pharyngoesophageal junction and to determine how these structures contribute to the development of the UES-HPZ.
  
  
  METHODS
  Prospective, experimental study.
  
  
  METHODS
  Tertiary Academic Medical Center.
  
  
  METHODS
  This study involved 18 healthy volunteers.
  
  
  METHODS
  We studied 5 participants by using a high-frequency US miniprobe (US-MP) and concurrent fluoroscopy and another 13 participants by using the US-MP and concurrent manometry.
  
  
  METHODS
  Relative contribution of various muscles in the UES-HPZ.
  
  
  RESULTS
  Manometrically, the UES-HPZ had a median length of 4.0 cm (range 3.0-4.5 cm). A C-shaped muscle, believed to represent the cricopharyngeus muscle, was observed for a median length of 3.5 cm (range 2.0-4.0 cm). The oval configuration representing the esophageal contribution to the UES was seen in 10 of 13 participants (77%) at the distal HPZ (esophagus to UES transition zone). The flat configuration of the inferior constrictor muscle was noted in 7 of 13 participants (54%) at the proximal HPZ (UES to pharynx transition zone). There were 4 to 5 wall layers versus 3 layers in the distal and proximal HPZ, respectively. The mean (+/- SD) muscle thickness was relatively constant along the length of the UES-HPZ.
  
  
  CONCLUSIONS
  Air artifacts in the UES-HPZ.
  
  
  CONCLUSIONS
  The configuration and layers of the UES-HPZ vary along its length. The upper esophagus is a significant contributor to the distal UES-HPZ.
authors.affiliation: Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Lyndon V
authors.initials: LV
authors.lastname: Hernandez
authors.forename: Kulwinder S
authors.initials: KS
authors.lastname: Dua
authors.forename: Sri Naveen
authors.initials: SN
authors.lastname: Surapaneni
authors.forename: Tanya
authors.initials: T
authors.lastname: Rittman
authors.forename: Reza
authors.initials: R
authors.lastname: Shaker
mesh_terms: D019160:Endosonography / Q000295:instrumentation*; D049631:Esophageal Sphincter, Upper / Q000033:anatomy & histology* / Q000502:physiology*; D005471:Fluoroscopy; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008365:Manometry; D011446:Prospective Studies; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted