Vertebral 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 |
The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the 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]
The vertebral arteries usually arise from the posterosuperior aspect of the central subclavian arteries on each side of the body, [2] then enter deep to the transverse process at the level of the 6th cervical vertebrae (C6), [1] or occasionally (in 7.5% of cases) at the level of C7. They then proceed superiorly, in the transverse foramen of each 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 [3] 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. [4]
Inside the skull, the two vertebral arteries join to form the basilar artery at the base of the pons. The basilar artery is the main blood supply to the brainstem and connects to the Circle of Willis to potentially supply the rest of the brain if there is compromise to one of the carotids. At each cervical level, the vertebral artery sends branches to the surrounding musculature via the anterior spinal arteries.
The vertebral artery may be divided into four parts:
Triangle of the vertebral artery is a region within the root of the neck and has following boundaries: [5]
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 Doppler ultrasound, CT angiography or phase contrast magnetic resonance imaging (PC-MRI).
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]
In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck.
Articles related to anatomy include:
A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system.
The circle of Willis is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including humans. It is named after Thomas Willis (1621–1675), an English physician.
In human anatomy, the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax. On the left side of the body, the subclavian comes directly off the aortic arch, while on the right side it arises from the relatively short brachiocephalic artery when it bifurcates into the subclavian and the right common carotid artery.
The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation.
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products. The neurovascular unit regulates cerebral blood flow so that activated neurons can be supplied with energy in the right amount and at the right time. Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions.
Spondylosis is the degeneration of the vertebral column from any cause. In the more narrow sense it refers to spinal osteoarthritis, the age-related degeneration of the spinal column, which is the most common cause of spondylosis. The degenerative process in osteoarthritis chiefly affects the vertebral bodies, the neural foramina and the facet joints. If severe, it may cause pressure on the spinal cord or nerve roots with subsequent sensory or motor disturbances, such as pain, paresthesia, imbalance, and muscle weakness in the limbs.
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.
In tetrapods, cervical vertebrae are the vertebrae of the neck, immediately below the skull. Truncal vertebrae lie caudal of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The vertebral transverse processes of mammals are homologous to the cervical ribs of other amniotes. Most mammals have seven cervical vertebrae, with the only three known exceptions being the manatee with six, the two-toed sloth with five or six, and the three-toed sloth with nine.
The basilar artery is one of the arteries that supplies the brain with oxygen-rich blood.
In anatomy, the left and right common carotid arteries (carotids) are arteries that supply the head and neck with oxygenated blood; they divide in the neck to form the external and internal carotid arteries.
Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies the medulla, pons, midbrain, cerebellum and supplies the posterior cerebellar artery to the thalamus and occipital cortex. As a result, symptoms vary widely depending which brain region is predominantly affected.
The vertebral vein is formed in the suboccipital triangle, from numerous small tributaries which spring from the internal vertebral venous plexuses and issue from the vertebral canal above the posterior arch of the atlas.
The inferior thyroid artery is an artery in the neck. It arises from the thyrocervical trunk and passes upward, in front of the vertebral artery and longus colli muscle. It then turns medially behind the carotid sheath and its contents, and also behind the sympathetic trunk, the middle cervical ganglion resting upon the vessel.
Vertebral artery dissection (VAD) is a flap-like tear of the inner lining of the vertebral artery, which is located in the neck and supplies blood to the brain. After the tear, blood enters the arterial wall and forms a blood clot, thickening the artery wall and often impeding blood flow. The symptoms of vertebral artery dissection include head and neck pain and intermittent or permanent stroke symptoms such as difficulty speaking, impaired coordination, and visual loss. It is usually diagnosed with a contrast-enhanced CT or MRI scan.
The inferior cervical ganglion is one of the three cervical sympathetic ganglia. It is situated between the base of the transverse process of the last cervical vertebra and the neck of the first rib, on the medial side of the costocervical artery.
The following outline is provided as an overview of and topical guide to human anatomy:
The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal cord is hollow and contains a structure called the central canal, which contains cerebrospinal fluid. The spinal cord is also covered by meninges and enclosed by the neural arches. Together, the brain and spinal cord make up the central nervous system.
Each vertebra is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species.