Читать книгу The Esophagus - Группа авторов - Страница 125

The UES “relaxes” with SPG‐controlled cessation of tonic vagal excitation, with a decrease in UES pressure within 0.2 s of swallow initiation [105]. The UES opens about 0.1 s later when it is pulled by the hyoid bone moving upward and forward during swallowing [91, 106]. The degree of opening is higher with larger boluses because of the higher intrabolus pressure generated by tongue thrust and descending pharyngeal contraction [67, 74, 77, 105]. UES opening is synchronous with laryngeal vestibule closure, both occurring earlier with a larger bolus despite similar pharyngeal propagation velocity. Augmentation of UES opening can be achieved with forceful voluntary prolongation of laryngeal excursion, termed the Mendelsohn maneuver [107]. Concurrent with arrival of the descending pharyngeal contraction, the UES closes just prior to the laryngeal vestibule opening [71].

The 1 s oropharyngeal swallowing stage includes only about 0.5 s of UES opening [75]. Oropharyngeal dysphagia can occur if the sphincter fails to open adequately when the UES is hypertrophic and/or fibrotic with a “cricopharyngeal bar” on videofluoroscopy [106]. Paralysis or weakness of oropharyngeal musculature following stroke or Parkinson’s disease can compromise pharyngeal bolus [108–111] and/or prevent hyoid movement that opens the UES.

Figure 5.6 Upper esophageal function by high‐resolution manometry. The left side of the figure shows the high‐resolution picture of the timing and pressures of a swallow event, with upper esophageal (UES) and lower esophageal sphincter (LES) relaxation. (A) Typical UES relaxation and opening with a swallow, and its closure with the arrival of the pharyngeal contraction that then propagates through the striated portion of the upper esophagus. (B) UES opening during belching. During a transient LES relaxation (TLESR), a common gastroesophageal cavity develops that leads to UES opening and gas venting. A pharyngeal contraction is absent.

Source: Reproduced from Kahrilas PJ, Pandolfino JE. Esophageal motor function. In: Yamada T, ed. Textbook of Gastroenterology, 5th ed.Hoboken, NJ: Wiley‐Blackwell; 2008.

Figure 5.7 Three‐dimensional pressure profile of the upper esophageal sphincter (UES). The pressures are higher in the anterior and posterior positions and lower on the sides. UESP, UES pressure.

Source:Welsh RW, Gray JE. Influence of respiration on recordings of lower esophageal sphincter pressure in humans. Gastroenterology1982; 83:590–594. © 1982, American Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.