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Topic

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Cricoid cartilage

The cricoid cartilage is a complete ring of hyaline cartilage forming the inferior portion of the larynx, located just below the thyroid cartilage and above the first tracheal ring. It is shaped like a signet ring, with a broad posterior lamina and a narrower anterior arch. The cricoid cartilage provides structural support to the airway, maintains patency of the subglottic space, and serves as an attachment site for the cricothyroid and cricoarytenoid muscles, as well as the ligaments of the larynx. Its anatomical features make it the only complete cartilaginous ring in the upper airway, critical for maintaining airway stability and for phonation mechanics.

Synonyms

  • Cricoid ring

  • Cartilago cricoidea

  • Laryngeal ring cartilage

Function

  • Maintains airway patency in the subglottic region

  • Serves as a support structure for the larynx

  • Provides attachment for intrinsic laryngeal muscles involved in voice modulation

  • Anchors ligaments connecting thyroid, arytenoid, and tracheal structures

  • Participates in phonation and airway protection during swallowing

MRI Appearance

T1-weighted images:

  • Cricoid cartilage appears as intermediate signal intensity relative to muscle

  • Air within the subglottic lumen appears as a signal void (black), outlining the cartilage

  • Surrounding soft tissues and fat are hyperintense, providing contrast for visualization

  • Calcification (in older adults) may appear as low-signal foci within the cartilage

T2-weighted images:

  • Cartilage is intermediate signal, while airway lumen remains signal void

  • Edema or inflammation in adjacent tissues appears hyperintense, highlighting pathology

  • Useful for detecting inflammatory changes, tumors, or cartilage degeneration

STIR (Short Tau Inversion Recovery):

  • Suppresses fat signal, improving visualization of edema or soft tissue pathology

  • Normal cricoid cartilage remains intermediate to low signal, while inflamed or tumorous areas appear hyperintense

  • Particularly valuable for early inflammatory or neoplastic changes around the subglottic region

CT Appearance

  • Cricoid cartilage appears as a soft tissue density ring surrounding the air-filled subglottic lumen

  • Air within the lumen appears hypodense (black), providing natural contrast

  • Calcification, ossification, or trauma is easily visualized as hyperdense areas

  • Axial, coronal, and sagittal views allow evaluation of airway patency, cartilage integrity, and relation to adjacent laryngeal structures

MRI images

Cricoid cartilage mri axial image -img-00000-00000_00001