Gross morphology of the bridges over the vertebral artery groove on the atlas (original) (raw)
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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)
Anatomical Variations of the Vertebral Artery in the Upper Cervical Spine
Regional Anesthesia and Pain Medicine, 2018
Background and Objectives: Accidental breach of the vertebral artery (VA) during the performance of cervical pain blocks can result in significant morbidity. Whereas anatomical variations have been described for the foraminal (V2) segment of the VA, those involving its V3 portion (between the C2 transverse process and dura) have not been investigated and may be of importance for procedures targeting the third occipital nerve or the lateral atlantoaxial joint. Methods: Five hundred computed tomography angiograms of the neck performed in patients older than 50 years for the management of cerebrovascular accident or cervical trauma (between January 2010 and May 2016) were retrospectively and independently reviewed by 2 neuroradiologists. Courses of the VA in relation to the lateral aspect of the C2/C3 joint and the posterior surface of the C1/C2 joint were examined. For the latter, any medial encroachment of the VA (or one of its branches) was noted. The presence of a VA loop between C1 and C2 and its distance from the upper border of the superior articular process (SAP) of C3 were also recorded. If the VA loop coursed posteriorly, its position in relation to 6 fields found on the lateral aspects of the articular pillars of C2 and C3 was tabulated. Results: At the C1/C2 level, the VA coursed medially over the lateral quarter of the dorsal joint surface in 1% of subjects (0.6% and 0.4% on the left and right sides, respectively; P = 0.998). A VA loop originating between C1 and C2 was found to travel posteroinferiorly over the anterolateral aspect of the inferior articular pillar of C2 in 55.5% of patients on the left and 41.9% on the right side (P < 0.001), as well as over the SAP of C3 in 0.4% of subjects. When present in the quadrant immediately cephalad to the C3 SAP, VA loops coursed within 2.0 ± 1.5 and 3.3 ± 2.5 mm on the left and right sides, respectively, of its superior aspect (P < 0.001). Conclusions: The VA commonly travels adjacent to areas targeted by third occipital nerve procedures and more rarely over the access point for lateral atlantoaxial joint injections. Modifications to existing techniques may reduce the risk of accidental VA breach.
Neurospine
Objective: Vertebral artery injuries during posterior cervical foraminotomy are rare, but can be fatal. Therefore, we investigated the anatomical correlation between the lateral recess and the vertebral artery. Methods: On axial cuts of cervical magnetic resonance imaging from 108 patients, we measured the distance between the vertebral arteries and the medial border of the facet joints. The anatomical vertebro-facet distance (AVFD), surgical vertebro-facet distance (SVFD), and vertebro-facet angle (VFA) were measured. Results: The mean AVFD values on the right side at the C3-4, C4-5, C5-6, and C6-7 levels showed statistically significant differences. On the right side, the mean SVFD values were equivalent to the AVFD values. The mean values of the VFA on the right side at all levels showed statistically significant differences. For all measurements, the greatest differences were seen between the C5-6 and C6-7 levels, and higher levels were associated with smaller distances from the lateral recess. The mean values of the AVFD on the right and left sides showed statistically significant differences at all levels, and the distances on the left were smaller than those on the right. Conclusion: The vertebral artery is closer to the lateral recess at higher cervical levels than at lower cervical levels. The largest distances were found at the C5-6 and C6-7 levels, and the left vertebral arteries were closer to the lateral recess than the right vertebral arteries.
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.
Variation of the Groove in the Axis Vertebra for the Vertebral Artery
The Journal of Bone and Joint Surgery, 1997
Transarticular screws at the C1 to C2 level of the cervical spine provide rigid fixation, but there is a danger of injury to a vertebral artery. The risk is related to the technical skill of the surgeon and to variations in local anatomy. We studied the grooves for the vertebral artery in 50 dry specimens of the second cervical vertebra (C2). They were often asymmetrical, and in 11 specimens one of the grooves was deep enough to reduce the internal height of the lateral mass at the point of fixation to ≤2.1 mm, and the width of the pedicle on the inferior surface of C2 to ≤2 mm. In such specimens, the placement of a transarticular screw would put the vertebral artery at extreme risk, and there is not enough bone to allow adequate fixation. Before any decision is made concerning the type of fixation to be used at C2 we recommend that a thin CT section be made at the appropriate angle to show both the depth and any asymmetry of the grooves for the vertebral artery.
Vertebral artery in relationship to C1-C2 vertebrae: an anatomical study
Neurology India, 2004
Ten randomly selected adult cadaveric specimens were dissected to analyse the anatomy of the vertebral artery during its course from the C3 transverse process to its entry into the spinal dural canal at the level of C1. In addition, 10 dry cadaveric C1-C2 bones were studied. The course of the artery and the parameters relevant during surgery in the region are evaluated. Ten adult cadaveric specimens and 10 adult dry cadaveric C1 and C2 bones were studied. In five cadaveric specimens, the arteries and veins were injected with coloured silicon. The artery during its course from the transverse process of C3 to the transverse process of C2 was labelled as V1 segment, the artery during its course from the C2 transverse process to the C1 transverse process was labelled as V2 segment and the segment of the artery after its exit from the transverse foramen of C1 to the point of its dural entry was labelled as V3 segment. The relationship of the artery to the C1-2 joint and facets, distance ...
Surgical and Radiologic Anatomy, 2005
The vertebral artery (VA) is often involved in the occurrence of complications after spinal manipulative therapy. Due to osteophytes compressing the VA anteriorly from the uncinate process or posteriorly from the facet complex, the VAs are susceptible to trauma in the transverse foramina. Such altered anatomical configurations are of major clinical significance, as spinal manipulations may result in dissection of the VA with serious consequences for the blood supply to the vertebrobasilar region. The purpose of this study is to describe numerous structural features of the third to seventh cervical vertebrae in order to contribute to the understanding of pathological conditions related to the VA. The minimal and maximal diameter of 111 transverse foramina in dry cervical vertebrae were studied. The presence of osteophytes and their influence on the VA were evaluated at the vertebral body and at the superior and inferior articular facets. The diameter of the transverse foramina increased from C3 to C6, while the transverse foramina of C7 had the smallest diameter. At all levels the mean dimensions of the left foramina were greater than those of the right side. Osteophytes from the uncinate process of C5 and C6 vertebrae were found in over 60% of dry vertebrae. Osteophytes from the zygapophyseal joints were more frequent at C3 and C4 vertebrae. About half of the osteophytes of the uncinate and of the superior articular process partially covered the transverse foramina. This was less common with those of the inferior articular facets. Osteophytes covering the transverse foramen force the VAs to meander around these obstructions, causing narrowing through external compression and are potential sites of trauma to the VAs potentially even leading to dissection. We strongly advocate that screening protocols for vertebrobasilar insufficiency (VBI) be used prior to any manipulation of the cervical spine and should include not only extension and rotation but any starting position from which the planned manipulation will be performed.
Evaluation of the groove for vertebral artery using CT angiography
Anatomy
Objectives: Groove for vertebral artery (sulcus arteriae vertebralis) is located on the posterior arch of the first cervical vertebra (atlas) where the vertebral artery passes over to reach the foramen magnum. The bony process between the posterior arch and the superior articulating process of the atlas is a common variation usually detected by lateral radiographies. This bony bridge is most commonly named as the ponticulus posticus. The aim of this study was to evaluate the existence of the ponticulus posticus and morphological features of the groove for vertebral artery. Methods: We performed a retrospective analysis of the groove for vertebral artery from 347 head and neck CT angiographies (694 bilaterally
Morphometric study of vertebral artery groove in dry human cervical vertebra in Pakistani population
Journal of Rawalpindi Medical College, 2021
Introduction: Vertebral artery passes through vertebral artery groove present on the posterior arch of atlas; free movement of which is required during rotation of the neck. This artery can be compressed if the vertebral groove is converted into arcuate foramina due to the projection of bony ponticuli over the grove. This compression can cause vertebra-basilar insufficiency, headache, or neck-shoulder pain of unknown origin. Objective: This study aims to provide data regarding vertebral artery groove and its morphology to help surgeons and clinicians in the local Pakistani population as no data is available in this population. Materials and Methods: A total of sixty adult dry human atlas vertebrae were taken from the Anatomy museum of King Edward medical university. Quantitative and qualitative data were taken for analysis. Quantitative data include the distance of medial and lateral edges of vertebral artery groove from the midline of the posterior arch, the distance of the medial ...
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.