Vertebral artery

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Vertebral artery
Arteries of the neck. The vertebral arteries arise from the subclavian arteries and join to form the basilar artery
Details
SourceSubclavian artery
BranchesBasilar artery
Posterior spinal artery
Anterior spinal artery
Posterior inferior cerebellar artery
VeinVertebral vein
Identifiers
Latinarteria vertebralis
MeSHD014711
TA98A12.2.08.002
TA24538
FMA3956
Anatomical terminology

The vertebral arteries are major

subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline basilar artery. As the supplying component of the vertebrobasilar vascular system, the vertebral arteries supply blood to the upper spinal cord, brainstem, cerebellum, and posterior part of brain.[1]

Structure

The vertebral arteries usually arise from the posterosuperior aspect of the central subclavian arteries on each side of the body,

cervical vertebra.[1] Once they have passed through the transverse foramen of C1 (also known as the atlas), the vertebral arteries travel across the posterior arch of C1 and through the suboccipital triangle[citation needed] before entering the foramen magnum.[1]

Nunziante Ippolito, a Neapolitan physician, identified the "angle of Nunziante Ippolito" to find the vertebral artery, between the anterior scalene muscle and the longus colli muscle.[3]

Inside the skull, the two vertebral arteries join to form the

anterior spinal arteries
.

Segments of vertebral artery anterior projection

The vertebral artery may be divided into four parts:

Triangle

Triangle of the vertebral artery is a region within the root of the neck and has following boundaries:[4]

The vertebral artery runs from base to apex (prior to entering the transverse foramen of 6th cervical vertebra).[citation needed]

The carotid tubercle separates the vertebral artery which passes directly behind it from the common carotid artery which lies directly in front of it. The ideal site for palpating the carotid pulse is to gently press the common carotid artery against the carotid tubercle.[5]

Variation

There is commonly variations in the course and size of the vertebral arteries, usually on both sides artery diameters are asymmetrical.[6] For example, differences in size between left and right vertebral arteries may range from a slight asymmetry to marked hypoplasia of one side, with studies estimating a prevalence of unilateral vertebral artery hypoplasia between 2% and 25%.[7] In 3-15% of the population, a bony bridge called the arcuate foramen covers the groove for the vertebral artery on vertebra C1. Rarely, the vertebral arteries enter the subarachnoid space at C1-C2 (3%) or C2-C3 (only three cases have been reported) vertebral levels instead of the atlanto-occipital level.[8]

The portion of vertebral arteries located within the skull (intracranial) have diameters of 3.17 mm. The intracranial length for the left vertebral artery (32.4 mm) is longer than the right (31.5 mm). The angle where vertebral arteries meet the basilar artery (vertebrobasilar junction), is 46 degrees.[9]

Vertebral artery dominance

Vertebral artery dominance (VAD) is typically a normal congenital vascular variation of the vertebral arteries. It refers to the asymmetry of the VA diameters on both sides, with the larger diameter being the dominant side and the smaller diameter being the nondominant side.[6]

In one study, the left vertebral artery diameter dominance was present in 54% of cases, while the right diameter was dominant in 30%. In 16% of cases, the left and right arterial diameters were equal.[10]

Function

As the supplying component of the vertebrobasilar vascular system, the vertebral arteries supply blood to the upper spinal cord, brainstem, cerebellum, and posterior part of brain.[1]

Clinical significance

As the supplying component of the vertebrobasilar vascular system, the vertebral arteries supply blood to the upper spinal cord, brainstem, cerebellum, and posterior part of brain.[1] A stroke of the arteries may result in a posterior circulation stroke.[citation needed]

Chiropractic manipulation of the neck has the potential to cause a vertebral arterial dissection.[11][12][13]

Diagnostics

Sagittal section
of the right vertebral artery on Doppler ultrasound

The condition and health of the vertebral carotid arteries is usually evaluated using

(PC-MRI).

Typically, blood flow velocities in the carotid artery are measured in terms of peak peak systolic velocity (PSV) and end diastolic velocity (EDV).[14]

Normally, vertebral artery blood flow velocity can be 63.6 ± 17.5 cm/s during PSV and 16.1 ± 5.1 cm/s during EDV according to a study done by Kuhl et al.[15] Due to vertebral artery dominance, measurements can vary on both sides, for example, another study by Seidel et al. found that the right side had an average of 45.9 cm/s and the left side 51.5 cm/s during PSV, and 13.8 cm/s on the right side and 16.1 cm/s on the left side during EDV.[14][16]

Additional images

  • The arteries of the base of the brain (inferior view).
    The arteries of the base of the brain (inferior view).
  • Diagram of the arterial circulation at the base of the brain.
    Diagram of the arterial circulation at the base of the brain.
  • Relationship of the vertebral artery to the suboccipital muscles.
    Relationship of the vertebral artery to the suboccipital muscles.

References

  1. ^ .
  2. .
  3. ^ "Ippolito, Nunziante". Trecanni.
  4. .
  5. .
  6. ^ .
  7. .
  8. .
  9. .
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  11. .
  12. ^ "Stroke Risk Associated With Aggressive Chiropractic Neck Adjustments". healthblog.uofmhealth.org.
  13. ^ ucsf.edu/news/2003/05/97065/chiropractic-treatment-neck-can-be-risk-factor-stroke
  14. ^ a b Themes, U. F. O. (December 30, 2019). "Ultrasound Assessment of the Vertebral Arteries". Radiology Key. Retrieved March 8, 2024.
  15. PMID 10666977
    .
  16. .

External links