Vertebral artery

Vertebral artery
Arteries of the neck. The vertebral arteries arise from the subclavian arteries and join to form the basilar artery
Details
Source	Subclavian artery
Branches	Basilar artery Posterior spinal artery Anterior spinal artery Posterior inferior cerebellar artery
Vein	Vertebral vein
Identifiers
Latin	arteria vertebralis
MeSH	D014711
TA98	A12.2.08.002
TA2	4538
FMA	3956
Anatomical terminology [edit on Wikidata]

The vertebral arteries are major

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.^[4]

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

The vertebral artery may be divided into four parts:

• The first (preforaminal) part runs upward and backward between the
  cervical vertebra, the sympathetic trunk and its inferior cervical ganglion
• The second (foraminal) part runs upward through the transverse foramina of the C6 to C2 vertebrae, and is surrounded by branches from the inferior cervical sympathetic ganglion and by a plexus of veins which unite to form the vertebral vein at the lower part of the neck. It is situated in front of the trunks of the cervical nerves, and pursues an almost vertical course as far as the transverse process of the axis.
• The third (extradural or atlantic) part issues from the C2 foramen transversarium on the medial side of the
  posterior arch
  of the atlas.

• ligamentum denticulatum. At the lower border of the pons, it unites with the vessel of the opposite side to form the basilar artery

  .

Triangle of the vertebral artery is a region within the root of the neck and has following boundaries:[5]

• Medial border of anterior scalene muscle (lateral)
• Lateral border of longus colli muscle (medial)
• Carotid tubercle (apex)
• First part of subclavian artery (base)

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.^[6]

There is commonly variations in the course and size of the vertebral arteries, usually on both sides artery diameters are asymmetrical.^[7] 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%.^[8] 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.^[9]

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.^[10]

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.^[7]

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.^[11]

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]

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.^[12][13][14]

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

Typically, blood flow velocities in the carotid artery are measured in terms of peak systolic velocity (PSV) and end diastolic velocity (EDV).[15]

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.^[16] 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.^[15][17]

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

External links

Wikimedia Commons has media related to Vertebral artery.

• Anatomy photo:28:09-0201 at the SUNY Downstate Medical Center
• Vertebral Artery | neuroangio.org
• MedEd at Loyola Neuro/neurovasc/navigation/vert.htm
• Atlas image: n3a8p1 at the University of Michigan Health System
• lesson5 at The Anatomy Lesson by Wesley Norman (Georgetown University) (vertebralcolumnfromleftweb)
• "Anatomy diagram: 13048.000-1". Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on January 1, 2014.
• "Anatomy diagram: 13048.000-3". Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on January 1, 2014.