What is the nerve supply of the cricopharyngeus (cricopharyngeal) muscle?

From the Guidelines

The cricopharyngeus muscle is primarily innervated by the pharyngeal branch of the vagus nerve (cranial nerve X) 1. This muscle forms the inferior portion of the inferior pharyngeal constrictor and constitutes the main component of the upper esophageal sphincter. The vagal fibers that supply the cricopharyngeus originate from the nucleus ambiguus in the medulla oblongata and travel through the pharyngeal plexus before reaching the muscle. Additionally, there may be some contribution from the glossopharyngeal nerve (cranial nerve IX) via the pharyngeal plexus, as seen in the context of oropharyngeal neurogenic dysphagia or oropharyngeal pain 2. The cricopharyngeus muscle plays a crucial role in swallowing by relaxing to allow food passage into the esophagus and contracting to prevent regurgitation and air entry into the esophagus during respiration. Understanding this innervation is important clinically when dealing with swallowing disorders, during procedures like cricopharyngeal myotomy, or when managing conditions like cricopharyngeal achalasia where the muscle fails to relax appropriately during swallowing. Key points to consider include:

• The vagus nerve's role in innervating the cricopharyngeus muscle 1
• The potential contribution of the glossopharyngeal nerve to the pharyngeal plexus 2
• The clinical significance of this innervation in swallowing disorders and related conditions.

From the Research

Nerve Supply of the Cricopharyngeus Muscle

• The cricopharyngeus muscle receives its nerve supply from the recurrent laryngeal nerve and the superior laryngeal nerve 3
• The recurrent laryngeal nerve supplies the posterior part of the muscular bundles of the cricopharyngeus muscle through its dorsal branch 3
• The superior laryngeal nerve supplies the anterior part of the cricopharyngeus muscle through its lateral branch 3
• This double vagal innervation of the cricopharyngeus muscle participates in the laryngo-pharyngeal coordination, especially for swallowing 3

Clinical Relevance

• Understanding the nerve supply of the cricopharyngeus muscle is important for the diagnosis and treatment of cricopharyngeal dysfunction 4, 5, 6, 7
• Botulinum toxin injections into the cricopharyngeus muscle have been shown to be effective in treating cricopharyngeal dysphagia 4, 5, 6, 7
• The efficacy of botulinum toxin injections can be assessed using various methods, including videofluoroscopic swallowing studies and functional oral intake scales 5, 7