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Persistent primitive trigeminal artery, lateral type. An incidentally discovered persistent primitive trigeminal artery (PTA) originating from the left internal carotid artery (ICA) in a patient who underwent clipping surgery for a ruptured anterior communicating artery aneurysm. Left ICA angiogram in AP (A) and lateral (B) views demonstrates a prominent PTA first coursing posterolaterally, then posteromedially to communicate with the upper basilar artery. CT-like axial image reconstruction of the three-dimensional rotational angiogram (3DRA) shows the PTA coursing near the apex of the petrous bone, reaffirming the lateral type PTA. Note that a small branch to the pons is originating from the PTA near the petrous apex in a magnified thin slice reconstructed axial 3DRA (arrow).
Source publication
The primitive carotid-vertebrobasilar anastomoses are primitive embryonic cerebral vessels that temporarily provide arterial supply from the internal carotid artery to the longitudinal neural artery, the future vertebrobasilar artery in the hindbrain. Four types known are the trigeminal, otic, hypoglossal, and proatlantal intersegmental arteries. T...
Contexts in source publication
Context 1
... sinus. Intracav- ernously, the PTA takes either a lateral/petrosal or a medial/sphenoidal course, and categorized as lateral or medial type. The lateral type PTA arises from the posterolateral aspect of the C4 segment of the ICA, courses lateral to the abducens nerve, and pierces the dura just medial to the sensory root of the trigeminal nerve (Fig. 4). 18) The medial type originates from the posteromedial aspect of the C4 ICA, courses medial to the abducens nerve, and pierces the dura of the dorsum sellae. 18) After piercing the dura, the PTA joins the distal third of the basilar artery. The frequency of the lateral and medial types had been reported to be approxi- mately equal for ...
Context 2
... the fact that the eighth cranial nerve remains in the petrous bone, and that the phylo- genic evidence showing dorsal aorta to longitudinal neural artery anastomosis at this level is lacking. 6) A rational diagnostic criteria set by Lie is as follows. (1) The POA should arise in the lateral portion of the petrous canal, close to the medial turn (Fig. 6, compare with Fig. 4). (2) The POA should run through the internal auditory meatus. (3) The POA should join the basilar artery at a caudal point. 36) Many previous reports have misdiagnosed a low-lying PTA or a stapedial artery remnant 37) as the POA. Using modern diagnostic modalities such as MRI/MRA and three-dimensional rotational angio- gram, more ...
Citations
... Carotid-basilar anastomoses are embryonic communications between the precursors of the carotid and vertebrobasilar circulations that supply blood to the hindbrain. While these primitive vessels are only present for a short period of time, from the 3-4 mm embryonic stage to the 7-12 mm stage [1], some anastomoses can persist into the adult period. A persistent trigeminal artery (PTA), derived from the embryonic primitive trigeminal artery, is the most common persistent primitive carotid-vertebrobasilar anastomosis, with historical and contemporary studies placing its incidence at approximately 0.5-0.7% ...
... The pathophysiology behind incomplete regression of the PTA remains poorly understood. Early embryonic development, starting at the 3-4 mm embryo stage (Carnegie stages 11 and 12), is characterized by the connection between the carotid arteries and the precursor to the vertebrobasilar circulatory system [1]. Four primitive anastomoses exist in total: trigeminal, otic, hypoglossal, and proatlantic intersegmental arteries; these transient vessels serve to temporarily supply oxygenated blood to the longitudinal neural artery, a forerunner of the vertebrobasilar artery, and eventually to the embryonic hindbrain. ...
... Basilar lesions, such as injury due to arterial wall dissection can lead to a broad assortment of gravely severe outcomes, ranging from many brainstem alternate syndromes to the dreaded Lockedin Syndrome [10,12,16]. The BA has also an utmost importance when treating stroke or aneurysms via endovascular procedures [26,32]. ...
... Also referred to as pre-communicating segment, it extends from the basilar tip to the point in which the PCA is joined by the PCommA. An anatomic variant in 1/3 of hemispheres is known as fetal configuration, in which P1 has a smaller diameter than the PCommA (or even more, completely absent) and the PCA emerges from the ICA, hence supplying blood flow as well to the posterior circulation [26]. ...
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.
... These vessels exist in the very early period of cerebral arterial development and rapidly involute within a week. Occasionally, persistence of the carotid to vertebrobasilar anastomosis is discovered in the adult period, and is considered a vestige of the corresponding primitive embryonic vessel [30]. ...
... In the petrous ICA it has also been described a thick "carotid cuff" [44], formed by connective tissue around the artery and a venous plexus. The origin of two branches can be identified from this portion, the caroticotympanic artery (which is inconsistent) and the pterygoid branch (present in approximately 30%) [30]. Additionally, it is worth noting that roughly in more than 80% of cases, there is a dorsal (endocranial) dehiscence of the petrous carotid canal, which can have critical clinical implications [16,34]. ...
Purpose
Knowledge of neurovascular anatomy is vital for neurosurgeons, neurologists, neuro-radiologists and anatomy students, amongst others, to fully comprehend the brain’s anatomy with utmost depth. This paper aims to enhance the foundational knowledge of novice physicians in this area.
Method
A comprehensive literature review was carried out by searching the PubMed and Google Scholar databases using primary keywords related to brain vasculature, without date restrictions. The identified literature was meticulously examined and scrutinized. In the process of screening pertinent papers, further articles and book chapters were obtained through analysis and additional assessing of the reference lists. Additionally, 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 documented in microscopic images.
Results
Encephalic circulation functions as a complex network of intertwined vessels. The Internal Carotid Arteries (ICAs) and the Vertebral Arteries (VAs), form the anterior and posterior arterial circulations, respectively. This work provides a detailed exploration of the neurovascular anatomy of the anterior circulation and its key structures, such as the Anterior Cerebral Artery (ACA) and the Middle Cerebral Artery (MCA). Embryology is also briefly covered, offering insights into the early development of the vascular structures of the central nervous system. Cerebral venous system was detailed, highlighting the major veins and tributaries involved in the drainage of blood from the intracranial compartment, with a focus on the role of the Internal Jugular Veins (IJVs) as the primary, although not exclusive, deoxygenated blood outflow pathway.
Conclusion
This work serves as initial guide, providing essential knowledge on neurovascular anatomy, hoping to reduce the initial impact when tackling the subject, albeit the intricate vasculature of the brain will necessitate further efforts to be conquered, that being crucial for neurosurgical and neurology related practice and clinical decision-making.
... 8 In the posterior circulation, the proximal vertebral artery (VA) originates from seventh dorsal cervical segmental arteries, while the rostral portion originates from the bilateral longitudinal neural arteries. 9 The boundary between these two regions is near the site where the extracranial VA transitions to the intracranial vertebrobasilar system. 10 In addition, the endothelial cells of the intracranial arteries are of neural crest origin, whereas those of the extracranial ICA and the vertebrobasilar system, up to the superior cerebellar artery, are of mesodermal origin. ...
Intracranial arterial disease (ICAD) is a heterogeneous condition characterized by distinct pathologies, including atherosclerosis. Advances in magnetic resonance technology have enabled the visualization of intracranial arteries using high-resolution vessel wall imaging (HR-VWI). This review summarizes the anatomical, embryological, and histological differences between the intracranial and extracranial arteries. Next, we review the heterogeneous pathophysiology of ICAD, including atherosclerosis, moyamoya or RNF213 spectrum disease, intracranial dissection, and vasculitis. We also discuss how advances in HR-VWI can be used to differentiate ICAD etiologies. We emphasize that one should consider clinical presentation and timing of imaging in the absence of pathology-radiology correlation data. Future research should focus on understanding the temporal profile of HR-VWI findings and developing quantitative interpretative approaches to improve the decision-making and management of ICAD.
... The fourth rhombomere (r4) will migrate to the second pharyngeal arch, while the sixth and seventh rhombomeres (r6 and r7) will populate the third, fourth, and sixth arches. Third and fifth rhombomere cells (r3 and r5) do not form part of any specific arch, as these are not involved in cell migration 13,14 (Fig. 2). Although the neural crest plays an essential role in the patterning, distribution, and development of the oropharyngeal apparatus, 14,15 recent studies have shown pharyngeal development can occur in the absence of NCC and that differentiation starts even before the neural crest migration. ...
The pharyngeal arches form the cornerstone of the complex anatomy of the face and neck. These embryologic structures are the foundation of face and neck development, and anomalous growth can result in craniofacial abnormalities. Surgeons who manage head and neck pathology and pathoanatomy will invariably encounter conditions associated with aberrant pharyngeal arch anatomy, and a thorough understanding of the normal and pathological development of these important structures is paramount to accurate diagnosis and treatment.
This manuscript is the first of a three-part educational series that addressed the pharyngeal/branchial arch embryology, development, nomenclature, and normal anatomy (Part I), pathologic anomalies of ear and neck derived from abnormal development of the arches (Part II), and different types of orofacial clefts, including Tessier clefts (Part III).
... Persistent proatlantal artery (PPA), which represents a primitive carotid-vertebrobasilar anastomosis (CVA), is extremely rare, with an incidence of 0.02%. 1) The PPA typically originates from the common carotid artery (CCA), internal carotid artery (ICA), or external carotid artery (ECA) and connects with the vertebral artery (VA) at the suboccipital space. 2) Although the PPA is the main blood supply for the vertebrobasilar system in these cases, acute ischemic stroke (AIS) due to basilar artery (BA) occlusion in patients with a PPA is extremely rare, and only three such cases have been reported previously, [3][4][5] only one of which was treated by mechanical thrombectomy (MT). 5) This report presents a case of AIS due to BA occlusion via a PPA who presented with disturbance of consciousness, quadriparesis, and anisocoria, which were treated by contact aspiration thrombectomy. ...
... On the other hand, a type 2 PPA originates from the ECA, passes through the C1-2 interspace and the transverse foramen of the atlas, and joins the extracranial VA before entering the foramen magnum. 2,8) In this case, since the PPA ascended to the suboccipital space without passing through the transverse foramen of the atlas and coursed between the atlas and occipital bone to enter the foramen magnum (Fig. 4), it was diagnosed as a type 1 PPA. Although many cases of PPA have been found incidentally, there are only a few reports of cases in which the PPA was directly related to the disease. ...
Objective: Persistent proatlantal artery (PPA) is a primitive carotid-vertebrobasilar anastomosis (CVA); acute ischemic stroke due to basilar artery (BA) occlusion via a PPA is extremely rare.
Case Presentation: An 84-year-old female developed disturbance of consciousness (Glasgow Coma Scale E2V1M5) and quadriparesis with a National Institutes of Health Stroke Scale score of 35. Head CT revealed early ischemic changes in the right temporal lobe, and a hyperdense vessel sign in the BA. Cerebral angiography showed that the left vertebral artery (VA) did not originate from the left subclavian artery or aortic arch. A left common carotid artery angiogram showed the presence of the left PPA originating from the left external carotid artery. Mechanical thrombectomy (MT) with contact aspiration using a Penumbra 5MAX ACE 60 aspiration catheter was performed, and successful recanalization was achieved after clot retrieval in the first attempt (thrombolysis in cerebral infarction scale 2b). MRI performed the following day, however, revealed a newly developed large hemorrhagic infarction in the pons, with no improvement in her symptoms (modified Rankin Scale score of 5 at 90 days).
Conclusion: Although MT achieved successful recanalization of the BA via the PPA, her clinical symptoms did not improve, probably because of poor collateral circulation or the long length of the occlusion. In patients with acute vertebro-BA occlusion, if the VA does not originate from the subclavian artery or aortic arch, the presence of a primitive CVA should be considered.
... The TA is the largest of the four anastomoses and the longest in existence [3,14]. The first evidence of the TA is found at the 3 mm embryonic stage [2,3]. ...
Purpose
The purpose of this study is to investigate the anatomical characteristics of persistent trigeminal artery (PTA) detected by computed tomography angiography (CTA) and magnetic resonance angiography (MRA), propose a modified classification and a novel grading system for basilar artery (BA).
Methods
Patients who underwent head CTA or MRA in our hospital between August 2014 and August 2022 were reviewed retrospectively. The prevalence, sex, and course of PTA were evaluated. PTA types were modified based on Weon’s classification. Type I to IV were similar to those in Weon’s classification except the presence of intermed fetal-type posterior cerebral artery (IF-PCA). Type V was the same as that in Weon’s classification. Type VI included subtypes of VIa (concomitant IF-PCA based on type I to IV) and VIb (other variants). BA was assessed based on a scale of 0 to 5 compared with PTA’s caliber (0, BA aplasia; 1 and 2, BA non-dominant; 3, equilibrium; 4 and 5, BA dominant).
Results
A total of 57 patients (0.06%) with PTA, including 36 females and 21 males, were detected in 94,487 patients. Six patients (10.5%) were medial type and 51 patients (89.5%) were lateral type. Thirty-seven patients (64.9%) were type I, 1 (1.8%) as type II, 13 (22.8%) as type III, 3 (5.3%) as type IV, 1 (1.8%) as type V, and 2 (3.5%) as type VI. For BA grading, 4 (7.0%), 21 (36.8%), 17 (29.8%), 6 (10.5%), 6 (10.5%), and 3 (5.3%) of the patients were grade 0, 1, 2, 3, 4, and 5, respectively. Fifteen patients (26.3%) had intracranial aneurysms. One cases (1.8%) had a fenestration of the PTA.
Conclusion
The prevalence of PTA in our study was lower than that in most previous reports. The modified PTA classification and BA grading system can be used to better understand the vascular structure of PTA patients.
... Simultaneously the carotid arteries soon establish their communication with the system of LNA and irrigate them via some transient anastomotic arterial channels, namely, the trigeminal artery (TA), otic artery (OA), hypoglossal artery (HA), and pro-atlantal artery (pro-A). These channels represent primitive carotid-vertebral anastomosis [6,7,8]. ...
... The communication between the dorsal aorta and the LNA, i.e., the VA, now replaces the role of the distal carotid-vertebral connections as feeders to the posterior circulation. Although there is an HA regression, the pro-A artery's distal portion remains the transverse suboccipital part of the VA [6]. Agenesis at any site of these normally present segments or the persistence of their embryonic connections can result in specific variations observed in VA. ...
Background
The vertebral arteries (VA) nourish the posterior cerebral circulation. Planning neck and cervical interventions like drilling and instrumentation, which involves VA manipulation, require an in-depth acquaintance with the normal and variant patterns encountered in the origin and course of the VA. Embryological events involved in forming these variant patterns can be correlated to their prior disposition in the lower vertebrate's understanding which becomes crucial while planning cervical interventions.
Study design
This is a single-center, retrospective study.
Materials and methods
The study involved 70 patients of both sexes and was done from September 2021 to February 2022 in the Department of Radiodiagnosis and Imaging at North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGRIHMS), Meghalaya, India. The CT angiographies were studied for variations of VA under V1 - from origin to entrance into the foramen transversarium (FT), V2 - part inside FT, V3 - from its exit from FT till it pierces the cranial dura mater, and 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 basilar artery 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 the aorta in 4.3% of subjects. One case presented a dual origin of VA. The abnormal origin of the LVA from the aorta showed a higher rate of abnormal entry into FT which was also found to be statistically significant.
Conclusion
Our study identifies and documents the anatomical variations present in VA specific to the population of northeast India by CT angiography and thus provides a much-needed reference for the healthcare professionals working in the field of Head and Neck interventions by providing opportunities further to understand these patterns for better diagnostic and therapeutic outcomes.
... www.nature.com/scientificreports/ VA is the longitudinal anastomosis of segmental meristem artery 17 . The bilateral VAs usually develop from the distal end of the seventh intersegmental dorsal arteries. ...
To investigated morphological variability of vertebral artery (VA) origin and its entrance level into cervical transverse foramina by computed tomography angiography (CTA). To retrospectively investigated CTA of 223 subjects (446 VA courses). Investigated were origin of the VA and its level of entrance into vertebral transverse foramen with notification of the sex and side of variation. The VA entered the C6 transverse process in 91.70% of specimens (409 out of 446 VA courses). Abnormal entrance of VA was observed in 8.30% of specimens (37 VA courses), with the level of entrance into the C3, C4, C5, or C7 transverse foramen at 0.22%, 2.47%, 4.71% and 0.90% respectively. Comparably, the overall variability of abnormal origin of VA was 1.57% (7 out of 466 VA courses), in which the left vertebral arteries all arose from aortic arch. The variation rate of vertebral entrance rose up to 50% in abnormal origin subgroup. When comparing subgroups of subjects with normal and abnormal origin, there was significance difference in the frequency of entrance variation in the level of transverse foramen ( p < 0.001). Abnormal entrance and origin of VA were observed in 8.30% and 1.57% of VA courses, which can be accurately appeared by CTA. Regarding to the subgroups of abnormal origin, the frequency of entrance variation was significantly increased in the level of transverse foramen compared to that of normal origin.
... 19 VA is the longitudinal anastomosis of segmental meristem artery. 20 The bilateral VAs usually develop from the distal end of the seventh intersegmental dorsal arteries. The proximal two-thirds of subclavian artery to the level internal thoracic artery is formed by the left seventh dorsal intersegment, while the distal third of the proximal subclavian artery is formed by the right seventh intersegment. ...
Objective
To investigated morphological variability of VA origin and its entrance level into cervical transverse foramina by CTA.
Methods
To retrospectively investigated computed tomography angiograms (CTA) of 223 subjects (446 VA courses). Postprocessing of source images was performed by using a multi-planar reformation (MPR), maximum intensity projection (MIP), multi-planar reconstruction (MPR) and volume rendering (VR) algorithms. Investigated were origin of the VA and its level of entrance into vertebral transverse foramen with notification of the sex and side of variation.
Results
The VA entered the C6 transverse process in 92.60% of specimens (413 out of 446 VA courses, 64.57% males and 28.03% females). Abnormal entrance of VA was observed in 7.40% of specimens (33 VA courses), with the level of entrance into the C3, C4, C5, or C7 transverse foramen at 0.22%, 2.24%, 4.72% and 0.22% respectively. Comparably, we observed that the overall variability of abnormal origin of VA was 3.14% (7 out of 223 subjects), which LVAs all arose from aortic arch (AA). Comparing subgroups of subjects with normal and abnormal origin, there was significance difference in the frequency of entrance variation in the level of transverse foramen.
Conclusion
Abnormal entrance and origin of VA were observed in 7.40% and 3.14% of cases, which can be accurately appeared by CTA.
