Medial occipital artery

At a glance

English

Medial occipital artery

Latin (TA2)

Arteria occipitalis medialis

System

Artery

Region

Head

Side

Paired, left and right

About the medial occipital artery

The medial occipital artery is one of the two vessels into which the posterior cerebral artery divides near the back of the midbrain, in its final segment, which neurosurgeons and radiologists call P4. The other terminal branch is the lateral occipital artery, which turns to the under surface of the temporal and occipital lobes. The medial occipital artery stays on the inner face of the hemisphere and supplies the occipital lobe on its medial side.

From its origin near the splenium of the corpus callosum it runs backwards along the medial surface, in or close to the calcarine and parieto-occipital sulci. Along the way it gives off several named branches. The calcarine branch follows the calcarine sulcus towards the occipital pole, the parieto-occipital branch climbs in the sulcus of the same name towards the precuneus, and a dorsal branch to the corpus callosum curls forwards over the splenium. Smaller cuneal and precuneal branches spread over the medial cortex.

Its territory is functionally important. The cortex along the calcarine sulcus is the primary visual cortex, and the cuneus and lingual gyrus on either side of it receive visual information from the opposite half of the visual field of both eyes. The artery also supplies the precuneus and the back of the corpus callosum. At its edges its branches meet those of the anterior cerebral artery over the upper medial surface and of the middle cerebral artery near the occipital pole.

Blockage of the medial occipital artery or its calcarine branch, usually by an embolus that has travelled up the vertebrobasilar system, causes loss of vision in the opposite half of the visual field, a homonymous hemianopia. Central vision is often preserved because the macular area at the pole may also receive blood from the middle cerebral artery. Larger infarcts that involve the splenium can add problems with reading.

Course and supply

Arises from

The posterior cerebral artery, as its medial terminal branch in the P4 segment near the splenium of the corpus callosum.

Ends in

Divides into calcarine, parieto-occipital, cuneal and precuneal branches and a dorsal branch to the corpus callosum.

Supplies

Supplies the occipital lobe on its inner surface, including the visual cortex along the calcarine sulcus, the cuneus, the precuneus and the splenium of the corpus callosum.