Figure 7: Digitally captured fluoroscopic images are shown from a 2-year-old castrated male Cavalier King Charles Spaniel with pharyngeal weakness related to immune mediated polymyositis. (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. A small quantity of barium contrast medium is present in the oral cavity (black arrows) with some residual barium in the proximal esophagus from the previous swallow (*). Aspirated barium is also seen in the larynx (LA) and proximal trachea. UES = upper esophageal sphincter. (b) The dorsal pharyngeal wall (DP) contracts ventrally to meet the tongue base (TB) but bolus propulsion is lazy and incomplete. The upper esophageal sphincter (UES) opens in a timely manner in relation to pharyngeal contraction. (c) After the bolus passes through the UES and the swallow is complete a moderate quantity of barium remains in the oral cavity.