2.1
Cricopharyngeal (CP) muscle dysfunction, also known as dysfunction of the upper oesophageal sphincter, occurs when the CP sphincter muscle fails to relax and open during swallowing. This may be caused by muscular or degenerative neurological disorders, or after head and neck surgery, or it may be idiopathic. Symptoms of CP muscle dysfunction include difficulty swallowing, painful swallowing, choking, regurgitation, cough, aspiration and weight loss.