Killian's dehiscence (Killian's triangle) is a weak area in the posterior pharyngeal wall through which a pharyngeal pouch (Zenker's diverticulum) herniates. This dehiscence lies between which two muscular components?

• A Between the oblique fibers of the inferior constrictor (thyropharyngeus) and the horizontal cricopharyngeus (upper esophageal sphincter) ✓
• B Between the middle and inferior pharyngeal constrictors at the level of the hyoid bone
• C Between the superior and middle pharyngeal constrictors behind the tonsil
• D Between the palatopharyngeus and stylopharyngeus muscles at the pharyngeal isthmus

Explanation

Killian's dehiscence is the anatomical weak point in the posterior pharyngeal wall between the oblique thyropharyngeus fibers (upper portion of inferior constrictor) and the more horizontally oriented cricopharyngeus muscle (lower portion of inferior constrictor / upper esophageal sphincter). The mucosa herniates posteriorly through this dehiscence to form Zenker's diverticulum, a false (pulsion) diverticulum. Endoscopic Zenker's diverticulotomy divides the cricopharyngeus. The other gaps (Laimer-Haeckermann's triangle, between cricopharyngeus and esophagus) are separate posterior wall weaknesses.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.