Basilar artery
Arteria basilaris
The basilar artery is formed where the two vertebral arteries join at the junction of the pons and medulla. It runs up the front of the pons and divides at the level of the midbrain into the two posterior cerebral arteries.
Overview
The basilar artery is about 3 cm long. It lies in the shallow basilar groove on the front of the pons, in the prepontine cistern, close to the clivus. Along its length it gives off short and long branches that encircle the pons, plus paired cerebellar arteries. At its upper end, the oculomotor nerve (CN III) passes between the superior cerebellar and posterior cerebral arteries. An aneurysm here can therefore compress CN III.
Anatomy
- Branches
The anterior inferior cerebellar arteries (AICA), the labyrinthine arteries (often arising from AICA), the pontine arteries (paramedian and circumferential), the superior cerebellar arteries, and finally the posterior cerebral arteries.
Function
- Supplies the pons, much of the cerebellum, the inner ear and, through the posterior cerebral arteries, the midbrain, thalami and occipital lobes.
Clinical significance
Basilar artery occlusion
Basilar artery occlusion causes coma, paralysis of all four limbs or locked-in syndrome. In locked-in syndrome the front of the pons is infarcted on both sides: the patient is fully conscious but can move only the eyes vertically and blink. Without emergency treatment the mortality is very high. Clot retrieval (thrombectomy) can save lives.
AICA infarction
AICA infarction causes a lateral pontine syndrome with sudden hearing loss and vertigo, because the labyrinthine artery is also blocked.
Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.