Intracranial region of the vertebral artery: morphometric study in the context of clinical usefulness (original) (raw)
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Scientific Reports, 2021
The intracranial segment of the vertebral artery (VA) is the unique part of the artery where the two VAs join to form a single vascular channel, viz. the basilar artery. In addition to this typical description, anatomical variations have been described; the presence of anatomical variation has been associated with some pathological processes, neurological complications, and the risk of vascular diseases in the posterior circulatory territory. We evaluated the typical anatomical features and variations of the VA4 component of the VA in a South African population to provide useful data on the prevalence of variation and morphometry of the distal VA. The study is an observational, retrospective chart review of 554 consecutive South African patients (Black, Indian, and Caucasian) who had been examined with multidetector computed tomography angiography (MDCTA) from January 2009 to September 2019. We observed various anatomical variations in the VA4 segment of the VA. We report the incidence of VA hypoplasia, hypoplastic terminal VA, and atresia. Fenestration and duplicate posterior inferior cerebellar artery (PICA) origin were also observed. The left intracranial VA was significantly larger than the right. Our study shows that anatomical variation of the intracranial VA is common in the population studied, with a total prevalence of 36.5%. Understanding the patterns of anatomical variations of the VAs will contribute significantly to the interpretation of ischemic areas and diagnosis of various diseases in the posterior circulatory territory.
Folia Morphologica
Background: The current study aimed to determine the origin of vertebral artery (VA) on both sides and the levels of entry into respective foramen transversarium (FT), to evaluate possible effects of sex on the entry levels, and to investigate the frequency of vertebral artery dominance (VAD) and vertebral artery hypoplasia (VAH) based on the vertebral artery V2 segment. Materials and methods: For this study, archived images of patients undergoing MDCT (Multidetector Computed Tomography) examination of the chest and head-neck for various reasons at Gaziantep University Medical Faculty Hospital were reviewed retrospectively. Three-dimensional reconstructions were performed for a total of 644 VA images from 322 patients using Horos software, and VA origin, the level of entry to FT and transverse diameters of both VA and FT were measured at the point of entry. Results: It was found that, among males, the VA originated from the truncus brachiocephalicus on the right side in only 1 patient and from the aortic arch in 2 patients on the left side. Left VA emerging from the aortic arch was observed in 2 females. The right vertebral artery was found to enter the FT at C3 in 1 male, at C4 in 6 patients (5 males, 1 female), at C5 in 19 patients (3 males, 16 females), and at C6 in 300 patients (141 males, 159 females. The left artery entered the FT at C5 in 23 patients (9 males, 14 females) and at C6 in 298 patients (141 males, 157 females). Looking at the relationship between variations of VA origin and the levels of entry to the FT, it was observed that only one of the left VAs originating from the arcus aorta entered the FT at C6 and at C5 in all others. On the right side, there was only one VA originating from the truncus brachiocephalicus, which entered the FT at C3. Of the remaining 248 vertebral arteries originating from the subclavian artery, 5 VAs entered the FT at C4, 14 VAs at C5 and 229 VAs at C6. The measurements of VA diameters showed right VA hypoplasia in 14 patients and left VA hypoplasia in 17 patients. Also, the right VA dominance was found in 110 patients and the left VA dominance in 128 patients. A moderate, positive correlation was observed between VA and FT diameters in both sides. A regression analysis showed that a 1 mm change in the right VA diameter was associated with a 75% change in the FT diameter and a 1 mm change in the left VA diameter caused a 72% change in the FT diameter. Conclusions: An understanding of VA variations and FT morphometry is crucial for informed clinical practice. This will clearly affect the success rates of physicians in the diagnosis and treatment of pathologies involving cervical region. The presence of any VA variation in a patient should be investigated on CT or MRI images prior to surgery.
Anatomic and radiologic analysis of the atlantal part of the vertebral artery
Journal of Clinical Neuroscience, 2009
The horizontal third segment (V3h) of the vertebral artery (VA) in 7 cadavers (14 sides) was dissected and the anatomical measurements recorded. Measurements from 24 healthy individuals (48 sides) were taken for comparison using multislice CT scanning. The distance between the medial tip of the VA V3h and the line passing through the mid point of the posterior tuberculum of the atlas was marked as length A. The distance between the medial tip of the VA V3h and the point penetrating the dura mater was classified as length B. The angle between these lines was the alpha (a) angle. Measurements were taken when the head was in a neutral position, as well as in maximum right and left rotation, extension and flexion. In cadavers, the mean a angle (±S.D.) was 82.42 ± 10.34°and 83.21 ± 10.81°on the right and left side, respectively. On multislice CT scanning, the mean a angle was 81.64 ± 10.15°on the right and 83.77 ± 10.65°on the left. These angles varied with the position of the head.
Purpose:The Vertebral arteries (VA) nourishes the posterior circulation supplying the brain. These variant patterns can be correlated to their development and such embryological variants should be well known before diagnosing or planning interventions in the head and neck regions. Methods: After due ethical clearence, CT angiography of 70 subjects were studied for variations of VA under, V1 – From origin to entrance into the FT (foramen transversarium), V2- Part inside FT, V3- from its exit from FT till it pierces the cranial Dura mater, V4- Intracranial part. Further, VA was observed for its origin, dominance, level of entry in FT, and any associated anomalies. Results:The VA was found mostly to be codominant. There was an opposite directional relationship between the BA curvature and the dominance of VA. The association of ischemic events with hypoplastic VA was more on the left side (66.67%). Left VA originated from Aorta in 4.3% subjects. 1.4% cases presented with dual origin of...
A study of variations in the origin of vertebral artery and its clinical significance
Objectives: An understanding of anatomy is essential to surgeons and knowledge of variations is of practical importance. The anatomic and morphologic variations of great vessels are significant for diagnostic and surgical procedures in the neck and thorax region. Vertebral artery is a branch of subclavian artery, generally arising from the first part of subclavian artery on both the sides. Multiple variations in the origin of vertebral artery have been reported in the literature, most common being directly from the arch of aorta, as a branch of thyrocervical trunk, as a branch of common carotid or external carotid artery. Material and methods: Study was carried out among 30 formalin fixed cadavers procured from Dr. D.Y. Patil Medical College, to note down the variations in the origin of vertebral artery. Results: Origin of right vertebral artery was normal in all the cases while the left vertebral artery showed varied origin. Conclusions: Anomalous vertebral artery origins may predisposes an individual to cerebrovascular disorders.
Morphometric analysis of the vertebral artery groove of the first cervical vertebra (atlas)
Pan Arab Journal of Neurosurgery, 2009
Background: Variations in the morphometry of the vertebral artery groove which presents on the superior surface of the posterior arch of the atlas behind its lateral mass may complicate surgical procedures in craniovertebral junction surgery. This necessitates preoperative information about the vertebral artery groove. Objective: The present study aimed at assessment of the quantitative and qualitative anatomy of the vertebral artery groove of the atlas on 76 dry specimens with comprehensive analysis. Methods: This included the study of different linear parameters of the vertebral artery groove such as the distance from the midline, the thickness, the depth of the lateral and medial entrances, the depth of the transverse foramen and the width of the transverse foramen. In addition, the different forms of posterior and lateral bridging over the groove and their percentages were assessed. Results: It was found that the minimum distance from the midline to the medial most edge of the vertebral artery groove in the inner and outer cortex of the posterior arch were 5 and 15 mm respectively. These data suggested that dissection of the posterior aspect of the posterior arch should remain 5 and 15 mm on the inner and outer cortex from the midline. It was also found that 44 (57.96%) of the examined specimens presented with a bridge formation which projects over the vertebral artery groove. From these 44 atlas presented with a bridge formation, 42 (55.26%) presented with partial bridges and 2 (2.63%) presented with complete posterior bridges. These bridges may interfere with the normal function of vertebral artery. Conclusion: It was concluded that before any craniovertebral intervention is performed, collection of the morphometric data of the vertebral artery groove must be carried out. (p66-71)
Bilateral Variation in the Origin of Vertebral Artery
During routine dissection we encountered variations in relation to origin of vertebral artery bilaterally. On right side vertebral artery arise from brachiocephalic trunk and on left side vertebral artery arises from arch of aorta. Vertebral artery is an important part of the circle of willis and it is important to posterior cerebral circulation. Abnormal origin of vertebral artery ''may favor cerebral disorders because of alterations in cerebral hemodynamics. An understanding of the variability of vertebral artery remains most important in angiography and surgical procedures where an incompatible knowledge of anatomy can lead to complications.
Variation in the Course of Vertebral Artery: A Case Report
2014
The study demonstrate a case of a cadaver in which right vertebral artery had an unusual course. It originates from the right subclavian artery and enters the foramen transversarium of the fourth cervical vertebra, while the left vertebral artery had normal course. The morphometric measurements of the arteries were performed. Anatomic and morphological variations of the vertebral artery are of immense importance in surgery, angiography and all non-invasive procedures.