Posterior vascular anatomy of the encephalon: a comprehensive review.

PURPOSE: This article presents a comprehensive exploration of neurovascular anatomy of the encephalon, focusing specifically on the intricate network within the posterior circulation and the posterior fossa anatomy; enhancing understanding of its dynamics, essential for practitioners in neurosurgery and neurology areas. METHOD: A profound literature review was conducted by searching the PubMed and Google Scholar databases using main keywords related to neurovascular anatomy. The selected literature was meticulously scrutinized. Throughout the screening of pertinent papers, further articles or book chapters were obtained through additional assessment of the reference lists. Furthermore, four formalin-fixed, color latex-injected cadaveric specimens preserved in 70% ethanol solution were dissected under surgical microscope (Leica Microsystems Inc, 1700 Leider Ln, Buffalo Grove, IL 60089, USA), using microneurosurgical as well as standard instruments, and a high-speed surgical drill (Stryker Instruments 1941 Stryker Way Portage, MI 49002, USA). Ulterior anatomical dissection was performed. RESULTS: Detailed examination of the basilar artery (BA), a common trunk formed by the union of the left and right vertebral arteries, denoted a tortuous course across the basilar sulcus. Emphasis is then placed on the Posterior Inferior Cerebellar Artery (PICA), Anterior Inferior Cerebellar Artery (AICA) and Superior Cerebellar Artery (SCA). Each artery's complex course through the posterior fossa, its divisions, and potential stroke-related syndromes are explored in detail. The Posterior Cerebral Artery (PCA) is subsequently unveiled. The posterior fossa venous system is explained, categorizing its channels. A retrograde exploration traces the venous drainage back to the internal jugular vein, unraveling its pathways. CONCLUSION: This work serves as a succinct yet comprehensive guide, offering fundamental insights into neurovascular anatomy within the encephalon's posterior circulation. Intended for both novice physicians and seasoned neuroanatomists, the article aims to facilitate a more efficient clinical decision-making in neurosurgical and neurological practices.

Composition of encephalic arteries and origin of the basilar artery are different between vertebrates.

Intracranial arterial anatomy is lacking for most mammalian and non-mammalian model species, especially concerning the origin of the basilar artery (BA). Enhancing the knowledge of this anatomy can improve animal models and help understanding anatomical variations in humans. We have studied encephalic arteries in three different species of birds and eight different species of mammals using formalin-fixed brains injected with arterial red latex. Our results and literature analysis indicate that, for all vertebrates, the internal carotid artery (ICA) supplies the brain and divides into two branches: a cranial and a caudal branch. The difference between vertebrates lies in the caudal branch of the ICA. For non-mammalian, the caudal branch is the origin of the BA, and the vertebral artery (VA) is not involved in brain supply. For mammals, the VA supplies encephalic arteries in two different ways. In the first type of organization, mostly found in ungulates, the carotid rete mirabile supplies the encephalic arteries, the caudal branch is the origin of the BA, and the VA is indirectly involved in carotid rete mirabile blood supply. The second type of encephalic artery organization for mammals is the same as in humans. The caudal branch of the ICA serves as the posterior communicating artery, and the BA originates from both VAs. We believe that knowledge of comparative anatomy of encephalic arteries contributes to a better understanding of animal models applicable to surgical or radiological techniques. It improves the understanding of rare encephalic variations that may be present in humans.

A rare variant of accessory posterior cerebral artery.

BACKGROUND: The posterior cerebral artery (PCA) leaves from the distal end of the basilar artery (BA) and is joined to the internal carotid artery (ICA) by the posterior communicating artery (PComA). METHOD: The archived computed tomography angiogram of a 67 y.o. male patient was studied anatomically. RESULTS: Anatomically normal PCAs left the BA. Both anterior choroidal arteries were found but the right one was hyperplastic. As the latter distributed parieto-occipital and calcarine branches, it was regarded as an accessory PCA. It was laterally to the normal one, inferior to the vein of Rosenthal. CONCLUSION: The terms "accessory PCA" and "hyperplastic anterior choroidal artery" describe the same morphology. Rare anatomical variants could benefit from a homogenous terminology.

An Update on the Superior Cerebellar Artery Origin Type.

Background and Objectives: The microanatomy of the superior cerebellar artery (SCA) is clinically significant. We, thus, aimed at patterning unilateral and bilateral possibilities of SCA origin. Materials and Methods: In total, 205 archived records of computed tomography and magnetic resonance angiograms were used. There were defined types of SCA origin from the basilar artery (BA): "0"-absent SCA, "1"-preterminal, "2"-collateral SCA, with SCA appearing as a terminal branch of BA, and "3"-SCA from the posterior cerebral artery (PCA) of the cerebral type. Fenestrations and duplications of SCA were recorded. Bilateral combinations of types were recorded as follows: A (1 + 0), B (1 + 1), C (1 + 2), D (1 + 3), E (1 + duplicated SCA), F (2 + 2), G (2 + 3), H (3 + 3), I (3 + duplicated SCA), J (1 + fenestrated SCA). Results: Type 0 SCAs were found in 0.25%, type 1 in 71.29%, type 2 in 19.06%, and type 3 in 9.41%. Absent and fenestrated SCAs were each found in a single case. The most frequent combinations were B (58.05%), C (13.17%) and F (13.17%). Bilateral symmetrical types occurred in 70.7% of cases. Fetal types of PCA and the artery of Percheron modified the BA ends. Combinations of C, F, and G changed the BA ends or tips; thus, different subtypes resulted in five BA bifurcation patterns, including five BA trifurcations and one BA quadrifurcation. BA trifurcation was also found in cases with duplicated SCAs. Conclusions: The SCA has various anatomical possibilities of origin and bilateral combinations that are not presented in anatomical lectures. Details on the specific end of the BA should be gathered on a case-by-case basis.

Association between the vertebrobasilar artery geometry and basilar artery plaques determined by high-resolution magnetic resonance imaging.

BACKGROUND: Atherosclerotic plaques are often present in regions of arteries with complicated flow patterns. Vascular morphology plays important role in hemodynamics. In this study, we investigated the relationship between the geometry of the vertebrobasilar artery system and presence of basilar artery (BA) plaque. METHODS: We enrolled 290 patients with posterior circulation ischemic stroke. We distinguished four configurations of the vertebrobasilar artery: Walking, Tuning Fork, Lambda, and No Confluence. Patients were divided into multi-bending (≥ 3 bends) and oligo-bending (< 3 bends) VA groups. The diameter of the vertebral artery (VA) and the number of bends in the intracranial VA segment were assessed using three-dimensional time-of-flight magnetic resonance angiography. High-resolution magnetic resonance imaging was used to evaluate BA plaques. Logistic regression models were used to determine the relationship between the geometry type and BA plaque prevalence. RESULTS: After adjusting for sex, age, body mass index ≥ 28, hypertension, and diabetes mellitus, the Walking, Lambda, and No Confluence geometries were associated with the presence of BA plaque (all p < 0.05). Patients with multi-bending VAs in both the Walking (20/28, 71.43% vs. 6/21, 28.57%, p = 0.003) and Lambda group (19/47, 40.43% vs. 21/97, 21.65%, p = 0.018) had more plaques compared to patients with oligo-bending VAs in these groups. In the Lambda group, the difference in diameter of bilateral VAs was larger in patients with BA plaques than that in patients without BA plaques (1.4 mm [IQR: 0.9-1.6 mm] vs. 0.9 mm [IQR: 0.6-1.3 mm], p < 0.001). CONCLUSIONS: The Walking, Lambda, and No Confluence geometry, ≥ 3 bends in the VAs, and a large diameter difference between bilateral VAs are associated with the presence of BA plaque.

Microvascular decompression for trigeminal neuralgia attributable to the vertebrobasilar artery: decompression technique and significance of separation from the nerve root.

BACKGROUND: Separation of the vertebrobasilar artery (VBA) from the trigeminal nerve root in microvascular decompression (MVD) is technically challenging. This study aimed to review the clinical features of VBA involvement in trigeminal neuralgia and evaluate surgical decompression techniques in the long term. METHODS: We retrospectively reviewed the surgical outcomes of 26 patients (4.4%) with VBA involvement in 585 consecutive MVDs for TGN using a Teflon roll for repositioning the VBA. The final operative status of the nerve decompression was categorized into two groups: the separation group and the contact group. Separation of the VBA from the nerve root was completed in 13 patients in the separation group, and slight vascular contact remained in the remaining 13 patients of the contact group. The clinical features of VBA-related TGN were investigated and the operative results were analyzed. RESULTS: Multiple arteries are involved in neurovascular compression (NVC) in most cases. The anterior inferior cerebellar artery was the most common concomitant artery (69%). The site of the NVC varies from the root entry zone to the distal portion of the root. All patients were pain-free immediately after surgery and maintained medication-free status during the follow-up period, except for one patient (3.8%) who had recurrent facial pain 8 years after surgery. Postoperative facial numbness was observed in six patients (23%). Of these, one patient showed improvement within 3 months and the other five patients had persistent facial numbness (19.2%). Other neurological deficits include one dry eye, one diplopia due to trochlear nerve palsy, two decreased hearing (< 50 db), two facial weaknesses, and two cerebellar ataxia. Although most of them were transient, one dry eye, two hearing impairments, and one cerebellar ataxia became persistent deficits. Statistical analyses revealed no difference in surgical efficacy or complications in the long term between the two groups. CONCLUSIONS: Slightly remaining vascular contact does not affect pain relief in the long term. Our study indicated that once the tense trigeminal nerve is loosened, further attempts to mobilize the VBA are not necessary.

Increased tortuosity of basilar artery might be associated with higher risk of aneurysm development.

OBJECTIVES: We analysed tortuosity of basilar artery (BA) to determine its relationship with the presence of aneurysm. METHODS: We retrospectively analysed 71 patients with BA aneurysms along with 71 age- and risk factors-matched control patients without BA aneurysm. From patients' medical records, we obtained their history including previous and current diseases and medications. For each patient, we calculated relative length (RL), sum of angle metrics (SOAM), triangular index (TI), product of angle distance (PAD) and inflexion count metrics (ICM). We used t-test and Mann-Whitney U test for continuous variables and χ2 test for dichotomised variables. To find independent predictors of BA aneurysm, we employed logistic regression analysis. RESULTS: We found significant positive correlation between age and SOAM (R = 0.195, p = 0.02) and PAD (R = 0.199, p = 0.018). Our study also showed that patients with BA aneurysm had significantly higher SOAM (0.21 ± 0.16 vs. 0.11 ± 0.08; p < 0.01), PAD (0.30 ± 0.19 vs. 0.18 ± 0.11; p < 0.01), TI (0.23 ± 0.23 vs. 0.10 ± 0.16; p < 0.01) and ICM (0.20 ± 0.16 vs. 0.15 ± 0.11; p = 0.045). In multivariate logistic regression analysis, after adjustment for all possible confounders, SOAM (OR = 1.086; 95% CI 1.046-1.136; p < 0.01) and TI (OR = 1.004; 95%C: 1.002-1.006; p < 0.01) remained independently associated with higher risk of BA aneurysm. CONCLUSIONS: Increased tortuosity of BA is associated with higher risk of its aneurysm development. KEY POINTS: • Basilar artery sum of angle metrics and product of angle distance are correlated with age. • Basilar artery tortuosity is independently associated with higher risk of its aneurysm development. • Basilar artery tortuosity is positively correlated with its diameter and bifurcation angle.

The segmentation of the posterior cerebral artery: a microsurgical anatomic study.

There are still different descriptions of the segmentation of the posterior cerebral artery, although there is a radiological and anatomical consensus on the segmentation of the anterior and the middle cerebral artery. This study aims to define the most appropriate localization for origin and end points of the segments through reviewing the segmentation of the posterior cerebral artery. The segments and the cortical branches originating from those segments of the 40 posterior cerebral arteries of 20 cadaver brains were examined under operating microscope. In this research, the P1, P2, P3, P4, and P5 classification of the segmentation of the posterior cerebral artery is redefined. This redefinition was made to overcome the complexities of previous definitions. The P1 segment in this research takes its origin from the basilar tip and ends at the junction with the posterior communicating artery. The average diameter of this segment at the origin was 2.21 mm (0.9-3.3), and the average length was 6.8 mm (3-12). The P2 segment extends from the junction with the posterior communicating artery to the origin of the lateral temporal trunk. This point usually situates on one level of posterior of the cerebral peduncle. The average diameter of this segment at the origin was 2.32 mm (1.3-3.1), and the average length was 20.1 mm (11-26). The P3 segment extends from the origin of the lateral temporal trunk to the colliculus where both the posterior cerebral arteries are the nearest to each other (quadrigeminal point) and is located at the anterior-inferior of the splenium. The average diameter of this segment at the origin was 1.85 mm (1.2-2.7), and the average length was 16.39 mm (9-28). The P4 begins at the quadrigeminal point and ends at the top of the cuneus. The average diameter of this segment at the origin was 1.55 mm (1.1-2.2). While the P5 segment is named as the terminal branches of the major terminal branches of the posterior cerebral artery, no definite border was found between the P4 and the P5 segments. In this study, the segmentation of the posterior cerebral artery, developed by Krayenbühl and Yasargil, was redefined to be more appropriate for radiological and anatomical purposes.

Basilar Artery Diameter Is Inversely Associated with Fetal Type Circle of Willis.

BACKGROUND: The relationship between basilar artery (BA) diameter and Circle of Willis (CoW) configuration has been scarcely investigated. We aimed to assess this association in community-dwelling older adults. METHODS: MRAs of 346 individuals were reviewed. Using generalized linear models adjusted for demographics and cardiovascular risk factors, we assessed the relationship between BA diameter and fetal and non-fetal types CoW, as well as the impact of this relationship on BA ectasia prevalence. RESULTS: In the total population, the mean BA diameter was 3.13 ± 0.68 mm and 7 subjects (2%) had ectasia (BA diameter >4.5 mm). In 248 subjects with non-fetal types CoW, the mean BA diameter was 3.32 ± 0.62 mm, and 2.8% had ectasia. In 98 subjects with fetal type CoW, the mean BA diameter was 2.66 ± 0.58 mm, and no individual had ectasia. The BA diameter was smaller in subjects with fetal type CoW than in those with non-fetal types (ß 0.65; 95% CI 0.51-0.79; p < 0.001). Individuals with fetal type CoW have an 18% reduction in BA diameter compared to those with non-fetal types, independently of demographics and cardiovascular risk factors. CONCLUSION: This study shows an inverse relationship between the BA diameter and the presence of fetal type CoW.

A comparison of basilar artery diameters measured by T2WI and TOF MR angiography.

PURPOSE: The purpose of our study is to compare basilar artery diameters (BAD) measured by T2WI to diameters measured by TOF MR angiography (MRA). By doing this, we hope to understand how compatible these two methodologies are with each other. METHODS: We used data from 100 patients (59 females, 41 males) who underwent a session of both T2W MRI and TOF MRA at the same time (ages between 18 and 83). We measured BAD by both T2WI and TOF MRA in three different levels. We then compared these diameters measured by two different methodologies to each other. RESULTS: In an area between the vertebrobasilar junction and posterior cerebral artery, all data measured by T2WI and TOF MRA in three different levels were analyzed. Average diameters measured by T2WI and TOF MRA turned out to be 79.5% correlated with each other. As a result of our mathematical model that we came up with through regression analysis, we calculated that measurements taken by T2WI on mid-pontine levels could predict TOF MRA measures with 78.3% accuracy. In T2WI and TOF MRA, average diameters measured were 2.982 ± 0.4717 and 3.205 ± 0.4281 mm, respectively. Statistical analyses showed that images measured by T2W series were significantly smaller than those measured by TOF MRA (p < 0.05). CONCLUSION: Our study showed that BAD measured by T2WI were smaller than those measured by TOF MRA. We think that it will be beneficial to refer our results to avoid T2WI and TOF MRA mismatch when evaluating BAD.

Diversity among posterior thalamoperforating branches originated from P1 segment: systematic review.

BACKGROUND: The P1 segment of the posterior cerebral artery (PCA) begins at the termination of the basilar artery and ends at the origin of posterior commu-nicating artery, within the interpeduncular cistern. Perforating branches arising from this segment are called posterior thalamoperforating arteries (TPAs) and the main and biggest artery among those is called TPA. Perforating branches are a crucial component of cerebrovascular system supplying the posterior part of the thalamus, subthalamus, hypothalamus, substantia nigra, perforated substance, posterior part of internal capsule and the nucleus of III and IV cranial nerve. It is very important for neurosurgeon to know the anatomy of perforating branches because of their susceptibility to injury. The aim of this study is to determine the morphometry of posterior TPAs and allow a better understanding of their bran-ching patterns and relation to basilar artery. MATERIALS AND METHODS: An extensive search was undertaken in order to identify published literature related to the posterior cerebral circulation system and the anatomy of posterior TPAs using key words. Medline, Embase, Ovid and Google Scholar databases were searched for publications dated from 1970 until July 2016. We collected and analysed all the data describing the mean number of branches per P1 segment, range of branches, number of analysed PCA, largest diameter of TPA, mean diameter of TPA and average distance from the basilar artery bifurcation. RESULTS: Thirteen cadaver studies were analysed and the data was extracted. We focused on the mean number of branches arising from P1 segment, perforators range, mean diameter of perforating branches, largest diameter of perforating branches. CONCLUSIONS: Mean number of branches per hemisphere was 2.91 (min. 1.51, max. 4.1). In more than half of analysed studies, authors did not find any pre-sence of posterior TPAs. Mean diameter of those perforators was 0.51 mm (min. 0.125 mm, max. 0.8 mm). Average distance from basilar artery bifurcation was 2.29 mm (min. 1.93 mm, max. 2.75 mm). There were many branching patterns presented by different authors.

Lateral Thalamic Infarction and the Vascular Geometry of the Posterior Cerebral Artery.

BACKGROUND: The geometric properties of the parental artery affect the development of local atherosclerosis and perforator infarction. In this study, we aimed at investigating the association between vascular geometry of the posterior cerebral artery (PCA) and the development of isolated lateral thalamic infarction (LTI), the most frequent type of thalamic infarction. METHODS: The geometric properties of the corresponding PCA in LTI patients were assessed and they include the diameters of the distal basilar artery (BA) and proximal PCA, distal BA - PCA angle, first PCA angle (angle between P1 and P2), and the presence of the posterior communicating artery (Pcom). These parameters obtained from the ipsilesional PCA were compared with the contralesional PCA and the corresponding PCA in age- and sex-matched controls. RESULTS: Forty-five LTI patients were enrolled. The ipsilesional PCA in LTI patients demonstrated a greater ipsilesional P1 - P2 angle (81.4 ± 22.6 vs. 71.3 ± 23.2°, respectively; p = 0.04) and a higher prevalence of Pcom (42.2 vs. 13.3%; p = 0.002) when compared to control subjects. In comparison with the contralesional PCA, ipsilesional PCA demonstrated a smaller diameter, larger angle between P1 and P2 segment, and a higher prevalence of Pcom. The presence of hyperlipidemia (OR 3.548 (1.283-9.811); p = 0.02) and Pcom (OR 3.507 (1.104-11.135); p = 0.03) was a factor that was independently associated with LTI. CONCLUSIONS: Local hemodynamics in the PCA may be influenced by the P1 - P2 angle and the presence of Pcom, which are associated with the development of LTI.

Predisposing factors in posterior circulation infarcts: a vascular morphological assessment.

INTRODUCTION: The aim of the study is to assess the effect of shape, diameter, elongation and deviation criteria of basilar artery (BA), convergence angle and diameter variations of vertebral arteries, and concurrent chronic diseases on posterior circulation infarcts. METHODS: Between January 2010 and May 2013, 186 patients who underwent brain and diffusion magnetic resonance imaging (MRI) with suspected cerebrovascular accident and were diagnosed with posterior circulation infarct and 120 infarct negative control subjects were included in this case-control retrospective study. Vertebral artery (VA) and BA diameter, right (R) and left (L) VA angles at the level of bifurcation, and BA elongation-deviation, and shape of BA were assessed in a total of 306 subjects. Ischemic lesions in the posterior circulation were classified according to their anatomical location and vascular perfusion areas. RESULTS: No significant difference was noted between the control and patient groups with respect to BA diameter (p = 0.676). The most effective risk factors for posterior circulation infarcts were as follows: BA elongation of 2 or 3, BA transverse location of 2 or 3, increase in left VA angle, and history of hypertension, hypercholesterolemia, and diabetes mellitus. CONCLUSION: Our results suggest that prominent elongation and deviation, C and J shape of BA, and increased L VA angle may be the predictors of at-risk patients in posterior circulation infarcts. Reporting marked morphological BA and VA variations detected at routine brain MRI will aid in selection of patients. Timely detection and treatment of at-risk patients may be life-saving.

Persistent primitive trigeminal artery: analysis of anatomical characteristics and clinical significances.

PURPOSE: The purpose of this study was to evaluate the classification of persistent primitive trigeminal artery (PPTA) based on computed tomography (CT) angiography, magnetic resonance (MR) angiography, and cerebral angiography and to review the clinical significance. MATERIALS AND METHODS: Images obtained by CT angiography performed between January 2011 and August 2013, MR angiography between January 2005 and January 2013, and cerebral angiography between January 2003 and November 2012 were analyzed for the presence of a PPTA. The diagnostic criterion for a PPTA was an artery that arises from the cavernous internal carotid artery and then joins the basilar artery (BA). We classified each PPTA by two different methods. First, the PPTA was classified as type 1, 2, 3, or 4 according to Weon et al.'s classification. Second, the classification of the PPTA was also made according to Salas et al.'s proposal, as a medial or lateral type. RESULTS: Eighteen of 8,900 patients (0.2%) had a PPTA. Of all 18 patients with a PPTA, nine were classified as type 1, two as type 2, six as type 3, and one as type 4. Seventeen PPTAs were a lateral type, and one was a medial type. Regarding the degree of BA hypoplasia, no hypoplasia was seen in six cases, moderate hypoplasia was identified in six cases, and severe hypoplasia was seen in six cases. CONCLUSIONS: This study revealed four types of PPTA according to Weon et al.'s classification. The presence of a PPTA should be considered by both the clinician and the radiologist who interprets the CT angiography, MR angiography, and conventional angiograms.

[The specific features of the anatomical structure of the artery of labyrinth (an anatomical and topographical study)].

The objective of the present work was to study syntopy of the artery of labyrinth using block-preparations of the posterior cranial fossa, variants of its branching-off from the vertebro-basiliar basin (VBB), and peculiar features of its anatomical structure. A total of 12 block-preparations of the posterior cranial fossa were available for the investigation. They were preliminarily stained with red latex and fixed in a three-point system. These procedures were followed by retrosigmoid craniotomy, opening of dura mater in the supero-lateral part of the cerebellomedulllary cistern, traction of the cerebellum, and blunt separation of the basiliar artery (BA). Variants of branching of the antero-inferior cerebellar artery (AICA) and branching of the artery of labyrinth from AICA were studied. It was shown that the artery of labyrinth branches off from the antero-inferior cerebellar artery in 100% of the cases. The latter artery formed a loop in 14% of the cases (3 ears). The average diameter of the labyrinth artery was 0.32 mm and its mean area 0.06 sq.cm. The artery of labyrinth branched off from the posterior para-stem segment of the antero-inferior cerebellar artery in 42.6% of the cases (9 ears), and from the anterior para-stem segment of AICA in 14.2% of the cases (3 ears). Within the conventional «rhombus¼, the artery of labyrinth was straight in 76.2% of the cases (16 ears) and arc-shaped in 23.8% (4 ears).

Three-dimensional analysis of foramen magnum and its adjacent structures.

The goal of this effort is to evaluate the anatomy of the foramen magnum (FM) using 3-dimensional computed tomography (3D CT), and determine whether or not the anatomical features of vascular structures and condylar foramen (CF) affect the types of FM.The CT angiography records of 101 patients (44 men and 57 women) were retrospectively examined in this study. Details of the FM, CF, and the vertebral and basilar arteries were examined using maximum intensity projection and 3D rendering images. The average age of the 101 patients was 45.28 ± 16.3 years. The 8 types of FM, in order of their frequency of occurrence, are as follows: round (19 cases; 18.8%), 2 semicircles (18; 17.8%), egg-shaped (15; 14.9%), hexagonal (14; 13.9%), tetragonal (11; 10.9%), oval (11; 10.9%), pentagonal (9; 8.9%), and irregular (4; 4%). There was no statistically significant relationship between the anatomical features of the vertebral and basilar arteries and the CF with the different types of FM (P ≥ 0.05). In our study, the diameter of the anteroposterior (AP) FM was 34.7 ± 3.6 mm, and the transverse (T) diameter was 29.5 ± 2.5 mm. The AP and T diameters were significantly higher in men than in women (P = 0.006 and P ≤ 0.001, respectively).Our study revealed that 3D CT is a safe and easy method for visualizing the anatomical structure of the FM and neighboring structures. Furthermore, this study was the first to demonstrate that there is no correlation between the 8 types of FM and the vertebral artery, basilar artery, and CF.

Arterial supply of the lower cranial nerves: a comprehensive review.

The lower cranial nerves receive their arterial supply from an intricate network of tributaries derived from the external carotid, internal carotid, and vertebrobasilar territories. A contemporary, comprehensive literature review of the vascular supply of the lower cranial nerves was performed. The vascular supply to the trigeminal, facial, vestibulocochlear, glossopharyngeal, vagus, spinal accessory, and hypoglossal nerves are illustrated with a special emphasis on clinical issues. Frequently the external carotid, internal carotid, and vertebrobasilar territories all contribute to the vascular supply of an individual cranial nerve along its course. Understanding of the vasculature of the lower cranial nerves is of great relevance for skull base surgery.

Variations and morphometric analysis of the proximal segment of the superior cerebellar artery.

INTRODUCTION: The superior cerebral artery is a clinically significant vessel, but little is known about its radiological anatomy. The aim of this study was to describe the anatomical variations of the proximal segment of the superior cerebellar artery using Computed Tomography Angiography. MATERIALS AND METHODS: The study group consisted of 200 subjects (54.5% female, mean age ± SD 56.2 ± 17.2 years) that had undergone head Computed Tomography Angiography. Subjects with any intracranial pathologies were excluded. Images in Maximum Intensity Projections were used to study the anatomical anomalies of the superior cerebellar artery. RESULTS: In 200 subject 388 superior cerebellar arteries were found. Twelve (3.09%) SCAs were duplicated in 11 patients and all originated from the basilar artery. In 8 (4.00%) patients the superior cerebellar artery was absent. The origin of the SCA was most often bilateral, mainly from the basilar artery (76.29%). The superior cerebellar artery diameter, measured at the site of the origin, was statistically significantly different depending on the place of the origin: wider when originating from the basilar artery as a single vessel (1.48 ± 0.42 mm vs. 1.34 ± 0.52 mm; p=0.03) and narrower when originating as duplicated one (1.38 ± 0.48 mm vs. 1.46 ± 0.44 mm; p=0.55). CONCLUSION: Superior cerebellar artery usually originates bilaterally from the basilar artery as a single trunk. Its diameter is significantly wider in that type in comparison to other anatomical variations.

Variations in diameters of vertebro-basilar tree in patients with or with no aneurysm.

INTRODUCTION: The morphological anatomy of the posterior circulation is very complex and variable. Aims of this research were to document the morphological anatomy of the posterior circulation along with variations in the Bosnian population, in patients with or without aneurysm. Measurements of the outer diameters of the vertebral artery, basilar artery and posterior cerebral artery were taken. The second aim was to determine the possible relationship between diameters of the area with subsequent aneurysm formation. MATERIAL AND METHODS: The study involved 60 consecutive patients, adults of both sexes, treated in the UKC Tuzla. The patients were divided into two groups. One group consisted of the patients without aneurysm of basilar artery, and the other group of patients with aneurysm. All the 60 patients were treated by means of MRI angiography. RESULTS: The mean diameter of the vertebral artery was 2.43 mm; 3.61 mm on the right and 2.83 mm; 3.94 mm on the left. The diameter of the basilar artery varied from 3.8 mm; 3.43 mm. The diameter of the posterior cerebral arteries 2.5 mm; 2.52 mm on the right and 2.46 mm; 2.62 mm on the left. CONCLUSIONS: We have documented the various morphometry variations as well as the differences of the anatomy in this area in Bosnian population as compared to the medicine literature.

Anatomical Features of Posterior Cerebral Arteries and Basilar Artery in 170 Anatolian Fresh Cadavers: Implications for Surgical Planning and Intervention.

BACKGROUND: The posterior cerebral arteries (PCAs) are terminal branches of the basilar artery (BA) and are responsible for the primary supply of the occipital lobe. Saccular aneurysm is most commonly seen close to the bifurcation of the BA. Various surgical interventions are performed for aneurysms. Therefore, the anatomy and localization of the BA and PCA are crucial. The aim of this study was to determine the characteristics of these arteries in a large Anatolian population. METHODS: The study included 170 Anatolian fresh cadavers. The diameters of the BA and PCA were measured. Correlations according to sex and age groups were analyzed. The Q1, Q2, and Q3 angles between the right and left PCA, between the right PCA and BA, and between the left PCA and BA, respectively, were measured. The location of the PCA relative to the sulcus pontocruralis (pontocrural groove) was also evaluated. RESULTS: The diameter of the artery increased with age and was higher in males than in females. Q1 and Q2 diameters were larger in males, while the Q3 diameter was larger in females. The Q1 angle between the right and left PCAs was found to be higher in age range 40-59 years with a mean of 87.33 ± 17.91 mm. Finally, the bifurcation point of the PCA was most frequently located above the sulcus pontocruralis (pontocrural groove) and least frequently located on the sulcus pontocruralis (pontocrural groove). CONCLUSIONS: The findings of our study will contribute to the planning of surgical approaches, the development of endovascular devices, the success of invasive procedures, and the reduction of complications.