Upper esophageal sphincter (also called pharyngoesophageal sphincter) within the hypopharynx
Esophageal cancer | Esophageal motility disorder | Upper esophageal sphincter | External sphincter muscle of male urethra | External sphincter muscle of female urethra | esophageal cancer | Esophageal atresia | Esophageal | Bladder sphincter dyssynergia |
It may promote acid reflux, also known as GERD, by relaxing the lower esophageal sphincter muscle.