Figure 6: Digitally captured fluoroscopic images are shown from a 5-year-old female Golden Retriever with no evidence of dysphagia. (a) This image is taken as the dog laps barium that is placed into the mouth using a catheter tipped syringe but before swallowing is initiated. Barium contrast medium is present in the oral cavity (black arrows) with some residual barium in the proximal esophagus from the previous swallow (*). NP = nasopharynx; LA = larynx; SP = soft palate; UES = upper esophageal sphincter. (b) The dorsal pharyngeal wall (DP) contracts ventrally to meet the tongue base (TB) and propels the liquid contrast medium caudally toward the upper esophageal sphincter (UES). The UES is wide open in coordination with caudal bolus propulsion. (c) After the bolus passes through the UES and the swallow is complete, only minimal barium remains in the oral cavity. An esophageal wave will propel the bolus from the proximal esophagus to the stomach.