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Crus helix of ear

The crus helix is an anatomical structure of the external ear (auricle), representing the superior and anterior extension of the helix as it curves inward above the opening of the external acoustic meatus. It forms a horizontal ridge just above the concha and contributes to the overall contour of the auricle, providing support and shape. The crus helix is composed of elastic cartilage covered by perichondrium and skin, and plays a role in directing sound waves into the external auditory canal.

Synonyms

  • Crus of helix

  • Helical crus

  • Superior helix root

  • Root of the helix

MRI Appearance of Crus Helix

PD (Proton Density) MRI Appearance

  • Appears as a thin, low signal intensity band due to dense cartilage composition.

  • Surrounding soft tissues and perichondrium may show slightly higher signal intensity.

  • Maintains a sharp outline against the adjacent fat of the auricular region.

STIR (Short Tau Inversion Recovery) MRI Appearance

  • Cartilage of the crus helix remains low signal (dark) due to low water content and suppression of fat.

  • Any edema, inflammation, or abnormality would appear as bright (high signal) in perichondrium or adjacent soft tissue.

  • Normally, no increased signal is seen in the cartilage itself.

T1-Weighted MRI Appearance

  • The crus helix shows low signal intensity (dark) compared to surrounding subcutaneous fat (which is bright).

  • The outline is well defined, with overlying skin being slightly higher in signal than the cartilage.

  • Helps differentiate cartilage from other auricular components, especially in trauma or tumor assessment.

MRI images

Crus helix of ear MRI images