Vertebral Artery
The vertebral artery is among the main arteries which supplies the brain.
It is the first and largest branch of the very first part of the subclavian artery.
ORIGIN, COURSE AND CONCLUSION
the vertebral artery originates from the upper aspect of the
initial part of the subclavian artery, runs vertically upwards to goes into the
foramen transversarium of the transverse process of C6. Subsequently it goes through
the foramen transversaria of the upper 6 cervical vertebrae.
After
appearing from the foramen transversarium of C1, it winds backwards around the
lateral mass of the atlas and enters the cranial cavity via foramen
magnum.
In the cranial cavity, it
links together with the vertebral artery of the opposite side at the lower
border of the Pons to create the basilar artery.PARTS
The vertebral artery is split into 4 parts.
- First (cervical) part-goes from origin to
foramen transversarium of C6 vertebra. This part is located in the
scalenovertebral triangle.
- Second
(vertebral) part-is located inside the foramen transversaria of upper 6
cervical vertebrae.
- Third
(suboccipital) part-goes from foramen transversarium of C1 vertebra to the
foramen magnum of skull. This part is located inside the
suboccipital triangle.
- Fourth
(intracranial) part-goes from foramen magnum to the lower border of the
pons.
BRANCHES
In the neck (cervical branches).
- Spinal
branches: They originate from the second (vertebral) part and goes into
the vertebral canal via intervertebral foramina to supply
the upper 5 or 6 cervical parts of the spinal cord.
- Muscular
branches: They originate from the first and third parts of the vertebral
artery. Those from the first part, supply deep muscles of the neck and
those from the 3rd part, supply the muscles of the suboccipital triangle.
In the
cranial cavity (cranial branches).
They
originate from the 4th part. These are:
- Meningeal
branches.
- Posterior
spinal artery.
- Anterior spinal
artery.
- Posterior
inferior cerebellar artery.
- Medullary
branches.
CLINICAL SIGNIFICANCE
Subclavian
steal syndrome: If there’s obstruction of the subclavian artery proximal to the
origin of vertebral artery, some amount of blood from opposite vertebral artery
will pass in a retrograde manner to the subclavian artery of the affected side
via the vertebral artery of that side to supply the collateral circulation to
the upper limb on the side of lesion. So there takes place a kind of
larceny of blood of brain by the subclavian artery of the affected side. For
this reason, the name subclavian steal syndrome.
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