Vessel
Posterior inferior cerebellar artery (PICA)
A variable route around medulla and cerebellar tonsil
High-yield
PICA contributes to lateral medullary supply, but a lateral medullary infarct can also follow vertebral-artery disease. The syndrome should not be equated automatically with an isolated PICA occlusion.
Overview
PICA commonly arises from the intracranial vertebral artery and follows a winding course around the medulla and cerebellar tonsil. Relations to IX, X and XI rootlets vary. Perforating, choroidal and cortical branches reach medullary and inferior cerebellar territories. Its size, origin and distribution complement neighboring cerebellar arteries.
Reference facts
- Origin
- Most commonly intracranial vertebral artery; extracranial, basilar, shared-trunk and other variants occur.
- Course
- Passes around the medulla near lower cranial-nerve roots, often loops caudally around the tonsil and then reaches the inferior cerebellar surface; the exact route varies.
- Branches
- Medullary perforators, fourth-ventricular choroidal branches and variable tonsillar, vermian and hemispheric cortical branches.
- Supplies
- Variable parts of lateral medulla, inferior cerebellar hemisphere/vermis, tonsil and fourth-ventricular choroid plexus.
Clinical correlation
Lateral medullary injury may combine same-sided facial and opposite-sided body pain-temperature loss with vertigo, ataxia, Horner syndrome, hoarseness or swallowing difficulty. Limb strength is often preserved in a restricted lateral lesion, but extensions can involve motor pathways.
Frequently asked questions
Where does the posterior inferior cerebellar artery (PICA) originate?
Most commonly intracranial vertebral artery; extracranial, basilar, shared-trunk and other variants occur.
What does the posterior inferior cerebellar artery (PICA) supply?
The posterior inferior cerebellar artery (PICA) supplies the variable parts of lateral medulla, inferior cerebellar hemisphere/vermis, tonsil and fourth-ventricular choroid plexus.
What are the branches of the posterior inferior cerebellar artery (PICA)?
Medullary perforators, fourth-ventricular choroidal branches and variable tonsillar, vermian and hemispheric cortical branches.
What is the course of the posterior inferior cerebellar artery (PICA)?
Passes around the medulla near lower cranial-nerve roots, often loops caudally around the tonsil and then reaches the inferior cerebellar surface; the exact route varies.