Question: An 82 year old male is referred to you for dysphagia. He brings with him a videofluoroscopic swallow study showing an upper esophageal diverticulum. You elect to perform an external diverticulotomy and cricopharyngeal myotomy (given a history of cervical spine fusion) suspecting a Zenker's diverticulum. To your surprise, the diverticulum sac is protruding through a muscular diastasis caudal to the cricopharyngeus. What kind of diverticulum is this? [Answer will be posted with next week's new question]

Answer to last week's question, Turn it Up (March 7, 2016):

Rollover. While neither particularly sensitive or specific to retrocochlear pathologies, this phenomenon is often seen in audiometric testing of an ear with a vestibular schwannoma.