The two vertebral arteries rise from the subclavian arteries, climb the neck through holes in the neck vertebrae (C6 up to C1), enter the skull through the foramen magnum and run up the front of the medulla oblongata, where they join at the lower edge of the pons to form the basilar artery. [1]
The 3D brain needs JavaScript. The text below still says where the vertebral artery is and what it does.
Opens with the blood-supply layer on (about 0.8 MB) and a side (sagittal) slice down the midline, so the two arteries are seen low on the front of the brainstem, below the pons, where they curve in to meet. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Lit: the left and right vertebral arteries from the foramen magnum (the lowest point of the medulla) up, curving inward over the front of the medulla to where they meet at the lower edge of the pons — only the part inside the skull. The part in the neck is cut off in this model, and the basilar artery they form is not lit (it has its own page). Every other artery shows in a darker colour. [2][1]
Each usually arises from the top of the subclavian artery at the root of the neck and enters the transverse foramen of the sixth cervical vertebra. [1]
It climbs through the transverse foramina of the neck vertebrae, crosses the back arch of the atlas (C1) and enters the skull through the foramen magnum. [1]
Inside the skull (its fourth, intracranial part) it pierces the dura, turns inward to the front of the medulla oblongata between the hypoglossal nerve and the first cervical nerve root, and at the medullopontine sulcus joins its partner to form the basilar artery. [1]
Of the two arteries that bring blood into the skull on each side, it is the back one: it enters through the foramen magnum, while the internal carotid enters through the carotid canal. [3]
What it does
As the source of the vertebrobasilar system, the vertebral arteries supply the upper spinal cord, the brainstem, the cerebellum and the back of the brain. [1]
Its largest branch, the posterior inferior cerebellar artery, supplies the back and side of the medulla oblongata, the choroid plexus of the fourth ventricle and the underside of the cerebellum. [4][5]
The anterior spinal artery, formed from both vertebrals, supplies the whole inner part of the medulla, and direct branches of the vertebral supply the strip between that and the posterior inferior cerebellar artery’s territory. [5]
Through the basilar artery and the posterior cerebral arteries it forms, its blood reaches the circle of Willis from behind. [1][6]
Other names
Latin: arteria vertebralis. It is described in four parts: V1 (preforaminal), V2 (foraminal, in the neck vertebrae), V3 (atlantic, round the atlas) and V4 (intracranial), the only part drawn here. [1]
Size
Inside the skull each is about 3.2 mm across and about 32 mm long (left 32.4 mm, right 31.5 mm in one study), and they meet the basilar at about 46°. [1]
The two often differ in width: in one study the left was the wider in 54% of people, the right in 30%, and they were equal in 16%; a markedly narrow vertebral on one side was estimated in 2–25%. [1]
On this model the left and right vertebral arteries (inside the skull) fit in a box about 28 mm front to back, 67 mm side to side and 39 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.