Download Vertebral artery

Chapter 21
The Vertebral Artery
Overview
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The first studies of the vertebral artery
were recorded as far back as 1844
Since that time the importance of the
vertebral artery has grown
considerably in stature, and is now
discussed in more detail than any
other artery by physical therapists
Anatomy
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The vertebral artery appears during the fifth
to sixth week of intra-uterine development,
from a posterior costal anastomosis
between the upper six cervical and
posterior-lateral intersegmental arteries
Along its course, the artery can be viewed
as four portions: the proximal, transverse,
suboccipital and intracranial portions
Anatomy
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The Proximal Portion
– This portion runs from the origin of the artery to
its point of entry to the cervical spine
– The vertebral artery usually originates from the
posterior surface of the subclavian artery, but it
can also originate from the aortic arch and
common carotid artery
– It runs vertically, slightly medial and posteriorly,
lateral to the longus colli and medial to the
anterior scalene, to reach the transverse
foramen of the lower cervical spine, although its
exact direction is dependent on its exact point of
origin
Anatomy
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Proximal portion
– Tortuosity and compression of this portion
of the artery is common
– The tortuosity and compression can be
congenital, muscular (due to compression
by the longus colli and scalene) or
because of advancing years
Anatomy
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Transverse Portion
– The transverse portion of the vertebral artery
runs from the point of entry at the spinal column
to the transverse foramen of C 2
– Throughout this section of the spinal column,
the artery travels vertically, in a true canal called
the transverse canal
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The transverse canal is formed by the bony transverse
foramina at each spinal level, the overlying anterior
and posterior intertransverse muscles, and the scaleni
and longus coli muscles
Anatomy
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Transverse portion
– Tortuosity of this portion of the artery can also
occur due to an abnormal origin of the artery
from the aorta
– The tortuosity is characterized by looping within
the intervertebral foramina, to the extent of
causing pedicle erosion, and a widening of the
intervertebral foramen with nerve root
compression, and even a fracture of the neural
arch
Anatomy
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Suboccipital Portion
– This portion of the artery extends from its
exit at the axis to its point of penetration
into the spinal canal
– The vertebral artery is most vulnerable to
compression and stretching at the C1-C2
level because of the amount of cervical
rotation that can occur at the atlantoaxial
joint
Anatomy
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The Intracranial Portion
– This portion of the vertebral artery runs from its
penetration of the dura mater into the arachnoid
space at the level of the foramen magnum, to
the formation of the basilar artery by the midline
union of the two arteries at the lower border of
the pons
– A major change in the structure of the artery
occurs as it becomes intracranial
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The tunica adventitia and tunica media become
thinner, and there is a gross reduction in the number of
elastic fibers in these coats
Anatomy
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Intracranial portion
– Due to these structural changes the
intracranial portion of the artery is prone
to mechanical obstructions to the artery,
including atherosclerotic plaques or
stenosis
Pathology
– Damage and occlusion of the vertebral arteries is
felt to occur because of the close proximity of
the vertebral artery and the bony and
ligamentous structures of the cervical spine
– Trauma to this area may lead to thrombosis,
dissection, transection, transmural hematoma,
pseudoaneurysm, and spasm of the vertebral
artery
– Vertebral artery compromise may also occur
because of atherosclerotic involvement of the
artery, sickle cell disease, rheumatoid arthritis,
arterial fibroplasias, an arteriovenous fistula, and
a number of congenital syndromes
Examination
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Clinicians need to be aware of the
signs and symptoms and consider
vertebral artery dissection early in the
differential diagnosis because of the
potential devastating neurological
consequences and in order to
decrease morbidity and mortality
Examination
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The testing of the vertebral artery has been
a routine part of patient screening by
manual therapists for many years, being
first described by Maitland in 1968
Traditionally, clinicians have relied solely on
existing manual pre-manipulative tests to
determine the appropriateness of a Grade V
technique, although it is not clear how
sensitive these tests are
Examination
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In those cases where the clinician is to
perform cervical mobilizations of Grade
I-IV, rather than a Grade V thrust
technique, the Australian
Physiotherapy Association’s Protocol
for Pre-manipulative Testing of the
Cervical Spine is recommended
Examination
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A positive vertebral artery test is one
in which signs or symptoms change,
especially if the changes evoked
include upper motor neuron signs
and/or symptoms
Examination
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Upper motor neuron signs and symptoms
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Dysphasia
Diplopia
Hemianopia
Ataxia
Hyperreflexia
Babinski response
Positive Hoffman or Oppenheim test
Examination
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Other UMN signs and symptoms
– Flexor withdrawal
– Nystagmus
– Quadrilateral paresthesia
– Bilateral upper limb paresthesia
– Peri-oral anesthesia
– Drop attacks
– Wallenberg syndrome
Intervention
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Following a positive vertebral artery test, or
positive responses in the history, the patient
must be handled very carefully, and further
intervention, particularly manipulation of the
cervical spine should not be delivered
The patient should not under any
circumstance, be allowed to leave the clinic
until their physician has been contacted,
and until the necessary arrangements have
been made for the safe transport of the
patient to an appropriate facility