Posterior inferior cerebellar artery

Origin and location

The artery originates from the intradural (intracranial) segment of the vertebral artery (a. vertebralis). Its site of origin is located slightly distal to the point where the vertebral artery enters the subarachnoid space, immediately before the two vertebral arteries merge into a single basilar artery.

Next, the vessel travels toward the inferior surface of the cerebellum, forming multiple anastomoses along its path with other arteries supplying cerebellar structures.

Branches of the posterior inferior cerebellar artery

Along its course, the artery gives rise to several important branches supplying structures of the posterior cranial fossa:

• Choroid plexus branch of the fourth ventricle (r. choroideus ventriculi quarti) — runs toward the choroid plexus of the fourth ventricle.
• Lateral and medial medullary branches (rr. medullares laterales et mediales) — run toward the medulla oblongata.
• Tonsillar branch of the cerebellum (r. tonsillae cerebelli) — runs toward the cerebellar tonsil.

What does the PICA supply?

The vascularization zone encompasses both cerebellar structures and the brainstem.

In the cerebellum, the artery supplies:

• The basal part of the cerebellar hemispheres.
• The inferior part of the cerebellar vermis.
• Part of the cerebellar nuclei.

In the brainstem, the artery supplies:

• The dorsolateral (retroolivary) zone of the medulla oblongata. This region includes the inferior cerebellar peduncles and the spinal trigeminal tract.

Variant anatomy and hemodynamic balance

Cerebellar arteries are characterized by pronounced asymmetry and interchangeability. The size and vascular territory of the posterior inferior cerebellar artery are inversely related to the basin of the anterior inferior cerebellar artery (a. cerebelli inferior anterior).

If the posterior inferior cerebellar artery is of small caliber on one side, blood flow deficit in the basal cerebellum is compensated by the ipsilateral anterior inferior cerebellar artery or the larger contralateral posterior inferior cerebellar artery.

In congenital hypoplasia (underdevelopment) of the vertebral artery, it may not participate in the formation of the basilar artery, but continue solely into the posterior inferior cerebellar artery.

Clinical significance

Features of the artery's topography are of clinical significance:

• Aneurysms: The junction of the vertebral and posterior inferior cerebellar arteries accounts for approximately 3% of all cerebral saccular aneurysms. Due to the vessel's location, rupture of such an aneurysm leads to hemorrhage directly into the subarachnoid space (SAH).

Not to be confused with: Pica chlorotica

The abbreviation PICA stands for the posterior inferior cerebellar artery. However, medicine features the Latin term Pica chlorotica, which has no relation to vascular anatomy. It is a symptom of pica (perversion of appetite): craving for chalk, coal, and other non-food substances, which is a sign of sideropenic syndrome in iron deficiency anemia.

Class and exam questions

What else to study on this topic

• The vertebral artery and its branches
• Anterior inferior cerebellar artery
• Blood supply to the medulla oblongata
• Subarachnoid hemorrhage (SAH)

Other topics in the "Anatomical Structures" section

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