The basilar artery is a single artery in the midline on the front of the brainstem. It forms where the two vertebral arteries join at the junction of the medulla and pons, climbs the groove (basilar sulcus) on the front of the pons, and divides at the junction of the pons and midbrain into the two posterior cerebral arteries. [1]
Lit: three arteries — the basilar artery and the left and right vertebral arteries, each vertebral from the foramen magnum up to where it joins the basilar (the part inside the skull). Every other artery shows in a darker colour. [2][1][3]
The 3D brain needs JavaScript. The text below still says where the basilar artery is and what it does.
Slice
Opens with the blood-supply layer on (about 0.8 MB), seen from the front and right: the basilar climbs the front of the brainstem from where the two vertebrals join, low in the middle of the view. The Side button slices down the midline. Tap a name under “The arteries lit here” to light the basilar or the vertebrals alone. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
It lies in the midline at the front of the brainstem, in the basilar sulcus on the front (ventral) face of the pons. [1]
It begins where the two vertebral arteries merge, at the junction of the medulla and pons, between the two abducens nerves, and ends at the junction of the pons and midbrain by dividing into the posterior cerebral arteries. [1]
Each vertebral artery climbs through the neck, enters the skull through the foramen magnum and runs up the front of the medulla oblongata to the medullopontine sulcus, where it joins its partner. [3]
What it does
Together the vertebral arteries and the basilar supply the upper spinal cord, the brainstem, the cerebellum and the back of the brain; the basilar is the main blood supply to the brainstem. [3]
The basilar feeds the pons and the upper and lower faces of the cerebellum through its pontine and cerebellar branches, and the inner ear through the labyrinthine artery. [1]
At its top it ends by splitting into the two posterior cerebral arteries, which join the circle of Willis — so it is the back (vertebral–basilar) source of the ring. [1][4]
Other names
Latin: arteria basilaris. With the two vertebral arteries it forms the vertebrobasilar system, the back of the brain’s two blood supplies. [1][3]
Size
The basilar artery ranges from 1.5 to 6.6 mm across. Inside the skull the vertebral arteries are about 3.2 mm across and about 32 mm long (left 32.4 mm, right 31.5 mm in one study), meeting the basilar at about 46°; the left was the wider in about 54% of people, the right in 30%, and they were equal in 16%. [1][3]
On this model the basilar and the two vertebral arteries (inside the skull) fit in a box about 39 mm front to back, 67 mm side to side and 65 mm top to bottom (the box they fit in, not their volume). [2]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.