The superior cerebellar artery (SCA) supplies blood to the upper surface of the cerebellum, parts of the pons, the cerebral peduncles, and the cerebellar peduncles. It is one of three paired arteries that feed the cerebellum, and its territory covers structures critical to coordination, balance, speech, and the relay of movement signals between the brain and body.
Where the SCA Originates and Travels
The SCA branches off the basilar artery near the top of the brainstem, just before the basilar splits into the two posterior cerebral arteries. From there, it curves around the brainstem, passing close to the oculomotor nerve, which controls most eye movements. Both the SCA and the nearby posterior cerebral artery help supply blood to this nerve in its early segment. The artery then wraps around and over the upper surface of the cerebellum, dividing into smaller branches that fan out across the top of the cerebellar hemispheres.
Structures the SCA Supplies
The SCA’s territory can be grouped into cerebellar and brainstem components.
On the cerebellar side, the artery feeds the entire upper (superior) surface of the cerebellum. This includes the outer cortex where fine-tuning of movement happens, as well as deep cerebellar nuclei, the clusters of neurons buried inside the cerebellum that serve as its main output centers. These nuclei are essential relay stations: they receive processed information from the cerebellar cortex and send corrective signals onward to the rest of the brain. The SCA also supplies the superior cerebellar peduncles, the thick bundles of nerve fibers that carry those output signals from the cerebellum up into the midbrain.
On the brainstem side, small perforating branches of the SCA supply portions of the upper pons and the cerebral peduncles, which are large fiber tracts in the midbrain that carry voluntary movement commands from the cerebral cortex down toward the spinal cord. By feeding both the cerebellar output pathways and the midbrain relay tracts, the SCA supports some of the brain’s most important circuits for coordinated, fluid movement.
How the SCA Fits With the Other Cerebellar Arteries
The cerebellum receives blood from three arteries on each side. The SCA covers the top, the anterior inferior cerebellar artery (AICA) covers the front-lower portion, and the posterior inferior cerebellar artery (PICA) covers the bottom and back. Each artery also feeds slightly different brainstem zones. Because of this division, a blockage in one artery tends to produce a recognizable pattern of symptoms, which helps clinicians identify which artery is involved.
What Happens When the SCA Is Blocked
When a clot or other obstruction cuts off blood flow through the SCA, the resulting stroke tends to cause a specific cluster of problems tied to the structures it supplies. The hallmark features are ataxia (loss of coordination affecting the limbs or trunk), dysarthria (slurred or poorly controlled speech), and nystagmus (involuntary, rhythmic eye movements). Many people with an SCA stroke have trouble walking because of the coordination loss.
Compared to strokes in the PICA or AICA territories, SCA strokes tend to produce more prominent ataxia and speech difficulty but less vertigo, headache, and vomiting. This pattern makes clinical sense: the upper cerebellum and deep nuclei that the SCA feeds are heavily involved in coordinating limb and speech movements, while the lower cerebellar regions supplied by PICA are more closely tied to balance-related dizziness and nausea signaling.
SCA strokes account for roughly 18% of all cerebellar infarcts, according to a study of vascular territory distribution. PICA strokes are more common at about 49%, and AICA strokes are least frequent at around 11%. Overall mortality for cerebellar strokes in that study was about 3%, though outcomes depend heavily on stroke size and whether dangerous swelling develops.
The SCA’s Role in Trigeminal Neuralgia
Beyond stroke, the SCA is clinically important because of its relationship to the trigeminal nerve, which carries sensation from the face. In many cases of trigeminal neuralgia, a condition that causes sudden, severe facial pain, the SCA is the offending vessel. As the artery loops near the brainstem, it can press against the trigeminal nerve at the spot where the nerve enters the brainstem (called the root entry zone). This compression, often on the upper or inner side of the nerve, damages the nerve’s insulating sheath over time and triggers the characteristic electric-shock-like pain.
When the SCA approaches the nerve from a different angle, running along the top or outer side instead of the inner side, the point of compression shifts to the middle portion of the nerve rather than the root entry zone. This anatomical detail matters for surgical planning. In microvascular decompression, a procedure used to treat severe trigeminal neuralgia, a surgeon places a small cushion between the SCA and the nerve to relieve the pressure. Understanding exactly where and how the artery contacts the nerve improves the precision and success of that operation.
Anatomical Variations
The SCA does not look identical in every person. It sometimes arises as two separate trunks from the basilar artery instead of one, a variation called duplication. Less commonly, it may share an origin with the posterior cerebral artery or follow an unusual looping path that brings it into closer contact with nearby nerves. These variations are generally harmless on their own, but they become relevant during brain imaging and surgery, where knowing the artery’s exact path helps prevent accidental injury and ensures accurate diagnosis of vascular problems.