Overview
The first branch of the subclavian artery, the paired
vertebral arteries course superiorly to merge within the cranium as the basilar
artery where they contribute to the posterior cerebral circulation.
Gross Anatomy
Arises from posterosuperior aspect of 1st part of subclavian
artery, and ascends pyramidal space between longus colli and anterior scalene, posterior
to internal carotid artery.
Enters foramen in transverse process of C6 and ascends
through foramina C6-C1
Passes out of C1 posteriorly, turning medially over the
posterior arch of C1.
Pierces dura and subarachnoid to enter the cranium via the foramen
magnum then courses supero-medially anterior to the medulla (passing anterior
to the roots of Hypoglossal nerve (CN XII)).
Joins with the vertebral artery from the opposite side at the
lower border of the pons to form the basilar artery.
Key branches:
Posterior inferior cerebellar artery
Anterior spinal
Posterior spinal (occasionally
arises from PICA)
Meningeal branches
Supplies:
Cervical spinal cord
Cranial meninges
Cerebellum
Anterior medulla
Posterior cerebral circulation
Gives off vertebral & muscular
branches in the neck
Clinical Anatomy
Vertebral artery
dissection; arises from tear in intimal layer of artery. Rarely spontaneous,
more often due to trauma. Less common than carotid artery dissection. Expanding
haematoma forms between intima and media, resulting in stenosis of vertebral
artery. This can lead to posterior circulation infarct.
Quick Anatomy
Key Facts
Aide-Memoire
Summary
The vertebral artery follows a relatively straightforward
course superiorly through the neck to supply spinal cord, cranial meninges and
posterior cerebrum and cerebellum. It is vulnerable to injury which can lead to
symptoms of a cerebrovascular accident / transient ischaemic attack.