Cricopharyngeus muscle (1 of 4)
Close-up view of the cricopharyngeus muscle. When contracted like this, the muscle squeezes shut the entrance to the esophagus. When a person swallows, the muscle relaxes, and the entrance to the esophagus opens dramatically to let food or liquid enter.

Cricopharyngeus muscle (2 of 4)
Same image as photo 1, but a small solid oval marks the center-point of the muscle’s grip, when contracted, and a larger dotted oval shows roughly how large the opening becomes when the muscle relaxes. Also, a yellow dotted line indicates the line of incision used when performing a cricopharyngeal myotomy (not needed in this patient).

Cricopharyngeus muscle (3 of 4)
More distant view of the cricopharyngeus muscle, as the camera has retracted upward and is now sitting in the postcricoid part of the hypopharynx, looking downward.

Cricopharyngeus muscle (4 of 4)
Much more distant view yet of the cricopharyngeus muscle, now framed within the hypopharyngeal inlet to the esophagus, at the top-center of the photo. Also now in view are the arytenoid mounds, at the bottom of the photo. Incidentally, this patient’s hypopharyngeal inlet to the esophagus is abnormally narrowed, due to post-surgery scarring; black dotted lines indicates the normal size of this inlet.