Basilar artery

The two vertebral arteries and the basilar artery are known as the vertebral basilar system, which supplies blood to the posterior part of the circle of Willis and joins with blood supplied to the anterior part of the circle of Willis from the internal carotid arteries.

Structure

The diameter of the basilar artery range from 1.5 to 6.6 mm.

Origin

The basilar artery arises from the union of the two vertebral arteries at the junction between the medulla oblongata and the pons between the abducens nerves (CN VI).

Course

It ascends along the basilar sulcus of the ventral pons. It divides at the junction of the midbrain and pons into the posterior cerebral arteries.

Branches

Its branches from caudal to rostral include:

• anterior inferior cerebellar artery
• labyrinthine artery (<15% of people, usually branches from the anterior inferior cerebellar artery)
• pontine arteries
• superior cerebellar artery