The cricopharyngeus is the lower part of the inferior pharyngeal constrictor that forms the upper oesophageal sphincter (UOS), maintaining tonic contraction at rest to prevent air entering the oesophagus during breathing and to prevent reflux of oesophageal contents into the pharynx. It must relax precisely in coordination with the swallowing sequence for the food bolus to enter the oesophagus, and failure of this relaxation (cricopharyngeal dysfunction) causes the pressure build-up that herniates through Killian's dehiscence to form a Zenker diverticulum.
| Origin | Lateral surface of the cricoid cartilage |
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| Insertion | Loops horizontally around the back of the pharyngoesophageal junction to the opposite side of the cricoid arch, without a median raphe |
| Nerve Supply | Pharyngeal plexus (CN X); Recurrent laryngeal nerve (CN X) |
| Blood Supply | Inferior thyroid artery |
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The coordinated relaxation of the cricopharyngeus requires intact vagal reflexes and brainstem swallowing centre function, explaining why neurological conditions affecting the brainstem produce cricopharyngeal dysfunction before peripheral pharyngeal muscle weakness.
The cricopharyngeus is the main component of the upper oesophageal sphincter, together with the lowest fibres of thyropharyngeus and the upper oesophageal muscle. Above it, between the oblique thyropharyngeus and the horizontal cricopharyngeus, lies a weak triangular area (Killian dehiscence) through which a Zenker (pharyngeal pouch) diverticulum herniates when the sphincter fails to open normally. Cricopharyngeal myotomy, open or endoscopic (for example stapler or laser division of the wall between pouch and oesophagus), treats Zenker diverticulum and cricopharyngeal dysfunction causing dysphagia. Botulinum toxin injection into the muscle is used as a diagnostic and therapeutic alternative. Videofluoroscopy and manometry assess the timing of sphincter opening relative to airway closure.
Not accessible to external palpation. Assessed by videofluoroscopic swallow study showing the UOS opening pattern.
Failure of UOS relaxation producing transfer dysphagia and aspiration managed with cricopharyngeal myotomy or Botulinum toxin injection.
