Volume 121, Issue 2, Pages 420-426 (August 2001) Dysphagia in a patient with lateral medullary syndrome: Insight into the central control of swallowing  Rosemary Martino, Norah Terrault, Frances Ezerzer, David Mikulis, Nicholas E. Diamant  Gastroenterology  Volume 121, Issue 2, Pages 420-426 (August 2001) DOI: 10.1053/gast.2001.26291 Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig.1 MRI 7 months after presentation.(A) T1- and (B) T2-weighted axial images and a (C) T1-weighted sagittal image show an infarct cavity confined to a small region of the dorsolateral medulla just anterior to the floor of the fourth ventricle and rostral to the obex. Gastroenterology 2001 121, 420-426DOI: (10.1053/gast.2001.26291) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig.2 Esophageal motility recording with 6-lumen perfused catheter system.The proximal recording site is 2 cm below the UES, and the distal site is 2 cm above the LES.Note absence of contraction just below the UES and presence of a peristaltic contraction through the distal two thirds of the esophagus.Sw, swallow. Gastroenterology 2001 121, 420-426DOI: (10.1053/gast.2001.26291) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig.3 Esophageal motility study with a 6-lumen perfused catheter system having a sleeve positioned in the UES.The proximal recording site is 3 cm above the sleeve.Note absence of relaxation and contraction in the UES and absence of contraction in the striated muscle of the pharynx just above the UES and the esophageal body just below the UES.Normal motor function is present in the esophageal body and LES below.Sw, swallow. Gastroenterology 2001 121, 420-426DOI: (10.1053/gast.2001.26291) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig.4 Cross-section of human brain stem and proposed site of lesion.Functionally, the lesion is positioned to spare the dorsomedial structures that would contain the CPG for swallowing in the NTS and the neighboring reticular formation, the dorsal motor nucleus of the vagus (DMNV), which serves the smooth muscle esophagus and LES, and perhaps the NA, which serves the striated muscle of the pharynx, UES, and upper esophagus.However, the lesion is positioned to interrupt the connections between the CPG circuitry and the NA serving these latter regions.XII, hypoglossal nucleus; Vn, trigeminal nucleus; Vt, trigeminal tract. Gastroenterology 2001 121, 420-426DOI: (10.1053/gast.2001.26291) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig.5 Overview of brain stem control mechanism for swallowing and proposed site of lesion.Functionally, the lesion is positioned to interrupt the connections between the CPG circuitry for swallowing in the NTS and the neighboring reticular formation and the NA region, which serves the striated muscle of the pharynx, UES, and upper esophagus.The CPG and its series of subnuclei within the NTS, the NA, and the dorsal motor nucleus of the vagus (DMNV), which serves the smooth muscle esophagus and LES, are largely unaffected. Gastroenterology 2001 121, 420-426DOI: (10.1053/gast.2001.26291) Copyright © 2001 American Gastroenterological Association Terms and Conditions