Inferior Pharyngeal Constrictor (Left) (Musculus constrictor pharyngis inferior)
Educational content only — not medical advice.
Anatomy
The inferior pharyngeal constrictor is the thickest and most powerful constrictor of the pharynx. Composed of two distinct components — the superior thyropharyngeus (oblique fibers) and the inferior cricopharyngeus (transverse fibers) — it forms the transitional sphincter between the pharynx and esophagus. The cricopharyngeus acts physiologically as the upper esophageal sphincter.
Origin & insertion
From the oblique line of the thyroid cartilage and lateral surface of the cricoid cartilage to the posterior median pharyngeal raphe (thyropharyngeal part) and continuous transverse fibers (cricopharyngeal part).
Action
Constricts the lower pharynx during swallowing; the cricopharyngeal component maintains tonic closure of the esophageal inlet and relaxes during bolus passage.
Innervation
Pharyngeal branch of the vagus nerve (cranial nerve X) via the pharyngeal plexus and recurrent laryngeal nerve.
Clinical notes
Killian dehiscence is an anatomical triangular area of weakness between the thyropharyngeal and cricopharyngeal fibers; increased intraluminal pressure can cause mucosal herniation through this triangle, resulting in a Zenker diverticulum.
Related structures
Educational references
FAQ
What is the role of the Inferior Pharyngeal Constrictor (Left)?
The inferior pharyngeal constrictor is the thickest and most powerful constrictor of the pharynx. Composed of two distinct components — the superior thyropharyngeus (oblique fibers) and the inferior cricopharyngeus (transverse fibers) — it forms the transitional sphincter between the pharynx and esophagus. The cricopharyngeus acts physiologically as the upper esophageal sphincter.
Why is the Inferior Pharyngeal Constrictor (Left) clinically important?
Killian dehiscence is an anatomical triangular area of weakness between the thyropharyngeal and cricopharyngeal fibers; increased intraluminal pressure can cause mucosal herniation through this triangle, resulting in a Zenker diverticulum.
Source & license
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