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Topic

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Thyroid cartilage

The thyroid cartilage is the largest of the laryngeal cartilages, forming the anterior and lateral framework of the larynx. It consists of two quadrilateral laminae that fuse anteriorly at the laryngeal prominence (Adam’s apple), with superior and inferior cornua projecting respectively upward and downward. The posterior edges remain open, articulating with the cricoid cartilage via the inferior horns, forming the cricothyroid joint, which permits movement critical for voice modulation. The thyroid cartilage provides structural support to the larynx, protects the vocal folds, and serves as an attachment site for laryngeal muscles and ligaments, including the thyrohyoid membrane, vocal ligaments, and extrinsic laryngeal muscles.

Synonyms

  • Adam’s apple

  • Laryngeal cartilage

  • Thyroid laminae

Function

  • Provides rigid support and protection to the laryngeal structures

  • Serves as an attachment point for vocal ligaments and laryngeal muscles

  • Plays a key role in phonation by adjusting vocal fold tension via the cricothyroid joint

  • Maintains shape and integrity of the laryngeal framework

MRI Appearance
T1-weighted images:

  • Thyroid cartilage appears as intermediate-to-low signal intensity, with ossified regions showing slightly higher signal

  • Surrounded by hypointense soft tissue and hyperintense fat, which helps delineate the cartilage margins

  • Non-ossified regions may appear slightly hypointense relative to ossified areas

  • Pathology such as fractures, tumors, or inflammation appears as disruption or abnormal signal intensity

T2-weighted images:

  • Cartilage generally remains intermediate to low signal, while surrounding soft tissue edema or inflammation appears hyperintense

  • Useful for evaluating trauma, inflammatory lesions, or tumor infiltration

STIR (Short Tau Inversion Recovery):

  • Fat suppression enhances visualization of edema or inflammatory changes in surrounding tissues

  • Normal cartilage remains low signal, whereas pathology appears hyperintense

CT Appearance

  • Thyroid cartilage appears as a well-defined, curvilinear bony or cartilaginous structure, depending on the degree of ossification

  • Surrounding air within the laryngeal lumen appears hypodense, providing excellent contrast for the anterior and lateral walls

  • Ossified portions are hyperdense, non-ossified cartilage is less dense but still distinguishable from soft tissue

  • CT is ideal for fracture assessment, calcification evaluation, and preoperative planning for laryngeal surgery

MRI images

Thyroid cartilage mri coronal image -img-00000-00000