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Lateral canthal ligament

The lateral canthal ligament is a crucial fibrous structure located at the outer corner of the eye, anchoring the eyelids to the orbital rim. It maintains the position and stability of the lateral canthus (outer eyelid angle), playing a significant role in eyelid function and facial aesthetics. Understanding its anatomy and imaging features is vital for diagnosing trauma, tumors, and planning oculoplastic surgeries.

Synonyms

  • Lateral palpebral ligament

  • Lateral retinaculum of the eyelid

  • Canthal tendon (lateral)

Function

  • Secures the lateral commissure (outer angle) of the eyelids to the lateral orbital tubercle (Whitnall’s tubercle) on the zygomatic bone

  • Maintains eyelid tension and contour

  • Supports proper eyelid closure and blinking

  • Preserves horizontal palpebral fissure shape

  • Prevents eyelid laxity and ectropion (outward turning)

MRI Appearance

  • T1-Weighted Imaging:

    • Appears as a low-signal (dark) linear band adjacent to the lateral orbital rim

    • May blend with adjacent fat and muscle, requiring thin slices for visualization

  • T2-Weighted Imaging:

    • Also shows as a low-signal (dark) linear structure

    • Surrounded by higher signal orbital fat, helping to delineate the ligament

    • Sometimes challenging to differentiate from adjacent tissues due to thinness

  • STIR (Short Tau Inversion Recovery):

    • Ligament remains low signal (dark)

    • High-signal suppression of orbital fat enhances contrast, making ligament more conspicuous

    • Useful in detecting edema or inflammation (appears as increased signal in pathologic conditions)

CT Appearance

  • Appears as a thin, dense linear structure at the lateral canthal region

  • Best visualized on high-resolution, thin-section axial or coronal images

  • Shows as a soft tissue density anchoring the lateral eyelid margin to the lateral orbital wall

MRI images

Lateral Canthal Ligament MRI IMAGE