Quiz- neck:

 

Can anyone identify the structure (arrowed) in this ultrasound video of the neck. What does it show and what is the event that is happening?  You may send your replies in the comments section, below.
OK folks- the answer is out: this sonographic video clip shows peristaltic activity within the cervical esophagus (the part of the esophagus extending from the glottis to the thorax). One can see echogenic (bright) particles (air bubbles and fluid) going down the lumen of the esophagus as the patient swallows.
In addition, further ultrasound video imaging shows (see below) some degree of reflux as fluid from the fundus of stomach (the upper part), regurgitates upwards into the lower part of the food pipe (esopahgus).

 This lady had undergone a total thyroidectomy (surgical removal of the entire thyroid). Hence, the thyroid gland is not visualized in these clips.