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Lamina of cricoid cartilage

The lamina of the cricoid cartilage is the broad, posterior plate of the cricoid cartilage, forming the back wall of the larynx. Unlike the anterior cricoid arch, the lamina is thicker and wider, providing attachment points for the posterior cricoarytenoid muscles, which are the primary abductors of the vocal cords. The lamina also forms the posterior boundary of the cricothyroid joint and contributes to the structural stability of the laryngeal framework, resisting deformation during swallowing, phonation, and airway pressure changes. It is quadrilateral in shape, with superior and inferior borders articulating with the thyroid and arytenoid cartilages, respectively.

Synonyms

  • Posterior plate of cricoid cartilage

  • Cricoid posterior lamina

  • Cricoid plate

Function

  • Provides attachment for intrinsic laryngeal muscles, including posterior cricoarytenoid and lateral cricoarytenoid muscles

  • Forms the posterior wall of the laryngeal airway, maintaining patency

  • Supports the cricothyroid joint, contributing to vocal cord tension control

  • Contributes to structural integrity and shape of the larynx

MRI Appearance

T1-weighted images:

  • Lamina appears as a hypointense (low signal) linear structure due to its cartilaginous composition

  • Surrounding paralaryngeal muscles and soft tissue show intermediate signal, while adjacent air within the laryngeal lumen appears as signal void (black)

  • Cartilage margins are clearly delineated against the low-signal background, and pathological changes such as ossification, degeneration, or tumors may alter the signal pattern

T2-weighted images:

  • Lamina remains low to intermediate signal, while surrounding soft tissue edema or fluid appears hyperintense

  • Air in the laryngeal lumen remains signal void, providing sharp contrast for evaluating posterior wall integrity

STIR (Short Tau Inversion Recovery):

  • Fat suppression removes paralaryngeal fat signal, allowing better visualization of edema or inflammatory changes

  • Lamina remains hypointense; pathological changes, such as inflammation, tumor infiltration, or cartilage injury, appear bright hyperintense

CT Appearance

  • Lamina appears as a hyperdense, slightly concave bony/cartilaginous plate forming the posterior wall of the larynx

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

  • Ossified cartilage is hyperdense, while non-ossified portions may appear slightly less dense than bone

  • Axial, coronal, and sagittal views clearly depict the lamina, its articulation with arytenoid and thyroid cartilages, and its contour

  • CT is particularly useful for evaluating trauma, ossification, neoplasms, and airway obstruction

MRI images

Lamina of cricoid cartilage mri axial image -img-00000-00000