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Supratrochlear artery

The supratrochlear artery is a small but important terminal branch of the ophthalmic artery, which itself is a branch of the internal carotid artery. This artery travels through the superior medial part of the orbit, emerges above the trochlea of the superior oblique muscle, and continues to supply blood to the forehead and scalp. Its superficial course and relationship to key facial structures make it significant in both clinical anatomy and imaging.

Synonyms

  • Frontal artery (sometimes used interchangeably, though technically a branch)

  • Arteria supratrochlearis (Latin)

  • Supra-trochlear branch of the ophthalmic artery

Function

  • Supplies oxygenated blood to the skin, muscles, and periosteum of the lower part of the forehead.

  • Contributes to the vascular network of the upper face and forehead, providing collateral circulation with branches of the angular and supraorbital arteries.

Imaging Appearance

MRI Appearance

  • T1-weighted images:

    • The supratrochlear artery appears as a flow void (black linear structure) due to the rapid flow of blood, with surrounding soft tissue demonstrating normal signal intensity.

  • T2-weighted images:

    • The artery typically also appears as a flow void (dark line or dot, depending on the plane). Adjacent soft tissues may appear brighter than on T1.

  • STIR (Short Tau Inversion Recovery):

    • The vessel itself remains a flow void; STIR suppresses fat signal, making the artery more conspicuous against the background of the suppressed bright orbital fat.

CT Appearance

  • Non-contrast CT:

    • The supratrochlear artery is not directly visualized unless it is calcified or abnormally enlarged. It appears as a small, tubular, soft-tissue density structure.

  • Contrast-enhanced CT:

    • The artery enhances brightly with contrast, appearing as a thin, enhancing structure along the superior-medial orbit and extending toward the forehead.

    • Best appreciated in high-resolution, thin-slice images.

MRI images

Supratrochlear artery mri image