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Superior hypophyseal artery

The Superior Hypophyseal Artery is a small but crucial vessel in the brain’s vascular system, playing a vital role in supplying blood to the pituitary gland and adjacent structures. Emerging from the internal carotid artery, it is responsible for nourishing the anterior pituitary (adenohypophysis), pituitary stalk, and portions of the optic chiasm and infundibulum. Its anatomical significance extends to endocrinology, neurosurgery, and neuroimaging due to its proximity to key neurovascular and endocrine structures.

Synonyms

  • Superior pituitary artery

  • Arteria hypophysialis superior (Latin)

  • Superior hypophyseal branch

Origin

  • Arises from the cavernous or supraclinoid segment of the internal carotid artery (ICA), usually medial to the origin of the ophthalmic artery.

  • Typically, it originates as several small branches rather than a single trunk.

Course

  • The superior hypophyseal arteries pass medially and slightly inferiorly from the ICA towards the pituitary stalk (infundibulum).

  • They course along the inferior surface of the optic chiasm, often branching into multiple fine vessels.

  • They pierce the diaphragma sellae (a small dural fold covering the pituitary) to supply the upper part of the pituitary gland, the infundibulum, and the lower part of the optic chiasm.

Function

  • Supplies arterial blood to:

    • The anterior lobe of the pituitary gland (adenohypophysis)

    • Pituitary stalk (infundibulum)

    • Diaphragma sellae

    • Inferior part of the optic chiasm

  • Critical for providing oxygen and nutrients to the pituitary, supporting endocrine function.

MRI Appearance

  • Not directly visible on standard MRI sequences due to its small size.

  • High-resolution contrast-enhanced MR angiography (MRA) or 3D TOF (Time-of-Flight) MRA may sometimes delineate these arteries as tiny flow-void structures near the suprasellar region.

  • Indirect evidence includes:

    • Enhancement of the pituitary stalk and gland, indicating perfusion.

    • In cases of vascular pathology (e.g., aneurysm, hypophyseal infarct), abnormal signal or enhancement in the pituitary stalk or adjacent structures.

CT Appearance

  • Generally not visualized on routine non-contrast CT due to their small caliber.

  • CT angiography (CTA):

    • May depict as minute enhancing vessels adjacent to the supraclinoid ICA, above the pituitary fossa, especially with high-resolution techniques.

  • Indirect findings:

    • Opacification or enhancement of the pituitary region after contrast administration.

    • Rarely, small aneurysms or vascular malformations related to the superior hypophyseal arteries may be detected.

MRI image

Superior hypophyseal artery MRI 3T axial image

CT image

Superior hypophyseal artery CT coronal anatomy image -img-00001-00001