Anatomy

Upper esophageal sphincter (UES / cricopharyngeus)

Also written as UES, cricopharyngeus, cricopharyngeal muscle, CP, pharyngoesophageal segment, PE segment.

The upper esophageal sphincter is a ring of muscle at the bottom of the throat that stays closed and opens to let a swallow into the food pipe.

The upper esophageal sphincter, usually shortened to UES, is a high-pressure area between the throat and the top of the esophagus (the food pipe). Its main muscle is called the cricopharyngeus, which is why some reports use that name, or just "CP," for the same place.

At rest this muscle stays squeezed shut. That keeps you from swallowing air down into the food pipe, and it helps keep what is in the esophagus from coming back up into the throat. When you swallow, it relaxes and is pulled open as your voice box moves up and forward, and the swallow passes through.

So a report describing the UES is describing a doorway: whether it opened, when it opened, and how much passed through.

Because this is the handoff point between the throat and the food pipe, clinicians look at whether it opens at the right moment in the sequence and wide enough for what was swallowed. Timing here is one of the things a moving X-ray study is designed to show. What any finding means for you is a discussion for your own medical team.