In cricopharyngeal dysfunction, regurgitation occurs due to impairment of which structure?

• A. Lower esophageal sphincter dysfunction.
• B. Esophageal motility disorder.
• C. Impaired relaxation of the upper esophageal sphincter leading to stasis and regurgitation.
• D. Pyloric sphincter spasm.

Answer: (C)

The main concept is that regurgitation in cricopharyngeal dysfunction comes from the upper esophageal sphincter failing to relax. The cricopharyngeus muscle forms this sphincter, and it normally relaxes in coordination with swallowing to let the bolus pass from the pharynx into the esophagus. When relaxation is impaired or the sphincter is overly tight, material collects above the sphincter (stasis). That trapped content can then be expelled backward into the pharynx or mouth, producing regurgitation. This proximal mechanism is distinct from lower esophageal sphincter problems or gastric outlet issues like pyloric spasm. An esophageal motility disorder could affect swallowing, but the specific regurgitation in cricopharyngeal dysfunction is due to impaired relaxation of the upper esophageal sphincter.