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There are multiple anatomical triangles of the skull base. However, to our knowledge, there has been no comprehensive review of these geometric landmarks. To allow for a safe and consistent approach to lesions of the skull base such as those near the internal carotid artery, internal acoustic meatus, and cavernous sinus, a comprehensive review of t...
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Context 1
... image shows paramedian triangle (Figure 2), also known as the supratrochlear triangle. Its borders are the oculomotor nerve, trochlear nerve, tentorial edge (and the dura extending between the dural entry points of the third and the fourth cranial nerves) [12]. ...
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Citations
... [2][3][4] Anteromedial triangle is suited for exposing superior orbital vein, ophthalmic vein and intracranial part of abducent nerve. 5,6 Similarly, anterolateral triangle anatomy is important in ICA aneurysm clipping surgeries and those surgeries addressing cavernous sinus pathologies, including fistulas and thrombosis. 7,8 Both these triangles can be approached via supraorbital extradural approach with temporal retraction. ...
... Anteromedial triangle was first described byMullan in 1979.14 By drilling in this area, between superior orbital fissure and foramen rotundum, sphenoid sinus can be reached.5 Watanabe et al., reports 11.7 x 7.8 x 12.0 mm as limits of anterolateral triangle.15 ...
Introduction: middle group of triangles and paraclival group is particularly significant due to its role in providing access to deep-seated structures such as the internal carotid artery, the cavernous sinus, clival structures, brain stem and cranial nerves. The objectives of this study was to delineate the borders of parasellar middle group and paraclival group triangles and to morphometrically evaluate of these triangles. Methodology: in a cross-sectional observational study design, conducted in Department of Anatomy from May 2021 to August 2022, borders, morphometry and contents of middle group of triangles (anteromedial, anterolateral, posteromedial and posterolateral triangles) and paraclival group (inferomedial and inferolateral triangles) were studied in 65 cranial fossa specimens. Results: The medial border of anteromedial triangle formed by ophthalmic nerve was the longest with average measurement of 13.05 mm (± 1.49 mm). The lateral border of anterolateral triangle formed by mandibular nerve was the shortest with average length of 6.01 mm (± 1.4 mm) and medial border formed by maxillary nerve was the longest with average measurement of 11.55 mm (± 2.15 mm). The medial border of posteromedial triangle formed by GSPN was the longest with average measurement of 16.8 mm (± 2.56 mm). The base of posterolateral triangle formed by GSPN was the longest with average measurement of 17.13 mm (± 3.16 mm). The lateral border of inferolateral triangle was the shortest with average length of 9.85 mm (± 1.44 mm) and base was the longest with average measurement of 14.84 mm (± 1.83 mm) Conclusion: morphometric measurements of middle group of triangles and paraclival group triangles, namely, anteromedial, anterolateral, posteromedial, posterolateral, inferomedial and inferolateral triangles are presented. This normative value acts as guidance for surgeons for planning the surgeries in the middle cranial fossa, approaches to cavernous sinus, paraclival regions
... The latter is intimately related with the V cranial nerve, lying inferomedial to Meckel's cave [23], where the Gasserian ganglion can be found, in the proximity of the VI nerve's entrance to Dorello's canal (below the posterior clinoid process, superior to the petroclival venous confluence [8,21,22]); afterwards it traverses in an antero-medial direction, heading to the apex of the petrous bone, parallel to its sagittal axis, to finally reach the aforementioned internal carotid canal orifice, and enter the cavernous sinus anteriorly to petrosphenoidal ligament or "Grubert's ligament", which extends from the petrous apex to the petrosal process of the sphenoid bone. Therefore, the horizontal portion, also related to the greater and lesser superficial petrosal nerves, surpasses the foramen lacerum (comprised by the union between the petrous apex, the lateral aspect of the dorsum sellae, and the sphenoid body) forming the anterior genu and ascends with a parasellar trajectory, emerging from the internal carotid canal, piercing the dura as it passes the petrolingual ligament, which bonds the petrous apex and the lingual process of the sphenoid bone, to become the next carotid segment [5,9,43]. ...
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.
... In the posterior part of the cavernous sinus, trochlear nerve is inferior to oculomotor nerve. In the anterior part, it turns upwards and at the level of optic strut, it becomes the most superior part of the cavernous sinus [12]. Trochlear nerve is always superior to the maxillary nerve. ...
... Paraclival, cavernous and paraclinoid segments of carotid artery and its relations are crucial for any skull base surgeries involving sellar region [20]. Though the endoscopic and transcranial view of the parasellar region differ significantly due to cavernous and clinoid segment of internal carotid artery hinders visualization of supratrochlear and infratrochlear triangles [12,21] in this study, the morphometric analysis of these triangles (in addition to clinoid and oculomotor triangles) is considered through transcranial views in order to generate the normative values and to understand the variations in the contents of these triangles. Exposure of clinoid segment of internal carotid artery and optic nerve delineates the clinoid triangle. ...
... Supratrochlear triangle: Wantabee reports dimensions of 10.9, 14.0, and 7.0 mm for medial, lateral and base measurements of this triangle [4]. Whereas, Doniel et al. reports measurement of 13.18, 14.27, and 5.51 mm respectively [12]. Results of this study (10.81, 14.94, 5.51 mm for medial, lateral and base) are similar to both these studies. ...
The objectives of this study were to delineate the borders of parasellar middle cranial fossa triangles and to morphometrically evaluate of these triangles. Methodology: in a cross-sectional observational study design, conducted in Department of Anatomy from May 2021 to August 2022, borders, morphometry and contents of parasellar middle cranial fossa triangles were delineated in fifteen cranial fossa specimens. Results: the medial border of clinoid triangle formed by optic nerve was the shortest with average length of 7.64 mm (± 0.59 mm) and lateral border formed by oculomotor nerve was the longest with average measurement of 14.5 mm (± 1.46 mm). The medial border of oculomotor triangle formed by interclinoid dural fold had average length of 9.05 mm (±1.07 mm) and lateral border formed by anterior petroclinoid dural fold had average measurement of 14.38 mm (±2.61 mm). The oculomotor nerve forming the medial limit of supratrochlear triangle measured 10.81 mm (±1.25 mm) and lateral trochlear nerve border measured 14.94 (±1.08 mm). Conclusion: morphometric measurements of parasellar middle cranial fossa triangles, namely, clinoid triangle, oculomotor triangle, supratrochlear and infratrochlear triangle are presented.
Разнообразие хирургических подходов к параселлярной области требует глубокого понимания микрохирургической анатомии. Целью данного исследования было определение границ параселлярных треугольников средней черепной ямки и морфометрическая оценка этих треугольников.Материалы и методы: в ходе перекрестного наблюдательного исследования, проведенного на кафедре анатомии с мая 2021 по август 2022 г., на пятнадцати образцах черепной ямки были определены границы, морфометрические параметры и содержимое параселлярных треугольников средней черепной ямки. Результаты: медиальная граница клиновидного треугольника, образованная зрительным нервом, была самой короткой, составляя в среднем 7,64 мм (± 0,59 мм) в длину, а латеральная граница, образованная глазодвигательным нервом, была самой длинной и достигала в среднем 14,5 мм (± 1,46 мм). Средняя длина медиальной границы глазодвигательного треугольника, образованной межклиновидной складкой твердой мозговой оболочки, составила 9,05 мм (±1,07 мм), а латеральной границы, образованной передней петроклиновидной складкой твердой мозговой оболочки, - 14,38 мм (±2,61 мм). Глазодвигательный нерв, формирующий медиальную границу супратрохлеарного треугольника, имел длину 10,81 мм (±1,25 мм), а латеральная граница по блоковому нерву - 14,94 мм (±1,08 мм). Заключение: представлены морфометрические параметры параселлярных треугольников средней черепной ямки: клиновидного треугольника, глазодвигательного треугольника, надблокового и подблокового треугольников.
... Notably, the distal intracavernous portion of the sixth cranial nerve lies infero-lateral to V1, as the abducens curves antero-inferiorly toward the superior orbital fissure. Please refer to Figure 6 for a visual representation of this triangle and its contents ( Figure 6) [18]. Extreme lateral triangle: The triangle is located between the maxillary and mandibular divisions of the V cranial nerve, with its medial anterior border being the lateral edge of V2 and its posterior border being the anterior edge of V3. ...
Background: The cavernous sinus (CS) is a complex anatomical structure that poses significant challenges to neurosurgeons performing surgical interventions in this region. A comprehensive understanding of the anatomy of the CS, including its relevant landmarks and structures, is crucial for successful surgical outcomes. Objective: This review aimed to provide a comprehensive overview of the anatomy of the CS, including relevant anatomical landmarks and structures, as well as surgical approaches for neurosurgeons. Methods: A literature search was conducted in electronic databases, including PubMed, Embase, and Scopus, using the keywords "cavernous sinus," "neuroanatomy," and "neurosurgery." Inclusion criteria included all articles published in the English language. Two independent reviewers screened the titles and abstracts, and relevant data was extracted from the included articles and synthesized for narrative synthesis. Results: A thorough comprehension of the eleven triangles in the parasellar region, medial fossa, and paraclival region is imperative for neurosurgeons to navigate complex anatomical structures during surgical approaches to the CS. These structures' anatomical relationships and spatial organization were summarized, along with an overview of relevant surgical approaches. Conclusion: The anatomy of the CS is complex and requires a thorough comprehension of the relevant anatomical landmarks and structures and surgical approaches. Neurosurgeons must comprehensively understand the eleven triangles in the parasellar region, medial fossa, and paraclival region to navigate the complex anatomical structures during surgical interventions effectively. This knowledge can enhance surgical precision and reduce the risk of complications, ultimately improving patient outcomes. KEY WORDS: Microsurgical Anatomy, Cavernous Sinus, Neurosurgical, Surgical Interventions.
... erefore, the dura that lies just posterior to the maxillary strut provides access to the lateral compartment of the CS. e relevance of this distinction may be extrapolated to the description of the contents of the anteromedial middle fossa triangle, [5] which has been used to achieve hemostasis of the CS. [11] e identification of the lateral border of the anterior wall of the CS may also be useful for other nontumoral pathologies such as encephaloceles and CSF leaks. ...
Background
The anterior wall of the cavernous sinus (CS) represents an important landmark for endoscopic surgery that although mentioned before, no precise anatomical boundaries have been described. We describe the anatomical landmarks that delimit the anterior wall of the CS, emphasizing its importance as a reference for accessing the CS through endoscopic approaches.
Methods
Six adult cadaveric heads fixed with formaldehyde and injected with colored silicone were studied. In all the heads, an endonasal endoscopic approach to the sellar and parasellar regions was performed and the anatomy of the anterior wall of the CS was studied.
Results
Four consistent anatomical landmarks that mark the limits of the anterior wall of the CS were found in all the specimens: anterosuperiorly, the lateral opticocarotid recess; posterosuperiorly, the medial opticocarotid recess; anteroinferiorly, the inferior part of the maxillary strut; and posteroinferiorly, the superolateral angle of the clival recess.
Conclusion
It is of paramount importance to recognize the anatomical landmarks that define the limits of the anterior wall of the CS to achieve a safe access to this so complex region.
... However, both methods provide limited exposure and could require excessive retraction of the temporal lobe, risking damage to the bridging veins or the lower cranial nerves [20]. He described the posteromedial triangle, now commonly referred to as "Kawase's triangle," as a region of the petrous bone devoid of vascular or neural structures that can be safely drilled away [11]. This approach decreased the likelihood of damage to the temporal lobe, brainstem, and cranial nerves while allowing improved exposure of the lower basilar for aneurysm clipping [11]. ...
... He described the posteromedial triangle, now commonly referred to as "Kawase's triangle," as a region of the petrous bone devoid of vascular or neural structures that can be safely drilled away [11]. This approach decreased the likelihood of damage to the temporal lobe, brainstem, and cranial nerves while allowing improved exposure of the lower basilar for aneurysm clipping [11]. Kawase's innovative response to the challenge of managing low-lying basilar aneurysms expanded our understanding of skull base anatomy. ...
... Kawase's innovative response to the challenge of managing low-lying basilar aneurysms expanded our understanding of skull base anatomy. The transpetrosal approach is now a standard part of skull base armamentarium and is utilized to treat a wide spectrum of pathologies of the vertebrobasilar junction, root of the trigeminal nerve, and anterolateral brainstem well beyond aneurysms alone [11]. ...
Basilar artery aneurysms account for approximately 5% of all intracranial aneurysms. This bibliometric analysis summarizes the most-cited articles on basilar artery aneurysms and highlights the contributing articles to today’s evidence-based practice. In the execution of this bibliometric-based review article, the Scopus database was used to perform a title-specific, keyword-based search for all publications until August 2022. The keyword “basilar artery aneurysm” or “basilar aneurysm” was used. Our results were arranged in descending order based on the article’s citation count. The 100 most cited articles were selected for analysis. Parameters included the following: title, citation count, citations per year, authors, specialty of first author, institution, country of origin, publishing journal, Source Normalized Impact Per Paper (SNIP), and Hirsch index. The keyword-based search showed that 699 articles were published between 1888 and 2022. The top 100 articles were published between 1961 and 2019. The top 100 most cited articles collected a total of 8869 citations with an average of 89 citations per paper. The rate of self-citations accounted for an average of 4.85% of the total number of citations. The bibliometric analysis provides a quantitative overview of how medical topics and interventions are analyzed in academic medicine. In the present study, we evaluated the global trends in basilar artery aneurysms by finding the top 100 most cited papers.
... It can also be included within the clinoidal triangle. [3] e loosening of third nerve and ICA by opening of this triangle, that constituted the superior wall of cavernous sinus -which can be maximized by opening of the clinoidal triangle, -allows medial mobilization of ICA and lateralization of CN III, exposing the posterior clinoid process, which can be removed especially in the context of exposing both SCA and P1 origins, the anterior portion of the second segment of posterior cerebral artery, the basilar artery, and its apex and ipsilateral PComA, and its perforating branches, [11] but also in approaching other pathologies in the high clivus through the cavernous sinus, with less risk to perforating branches in comparison to its adjacent, the optic-carotid triangle [ Figure 3b]. [6] Furthermore, the liberation of CN III before its lateralization reduces the risk of postoperative palsy secondary to manipulation injury. ...
... Described by Parkinson in 1964, [9] this triangle is composed by the superior margin of V1 and inferior border of CN IV, and a line that connects the entrance of both nerves into the dura-mater covering the cavernous sinus, relying entirely on the lateral wall of the cavernous sinus. [3] If the extradural approach is chosen, initially a middle fossa peeling is performed, removing the outer layer of the lateral wall of cavernous sinus and exposing the reticular layer that constitutes its inner part. at allows the direct visualization of both nerves and their exploration. ...
... [1] Furthermore, by drilling the bone between superior orbital fissure and foramen rotundum, the sphenoid sinus is open. [3] Anterolateral or lateral triangle is narrow triangle, described by Dolenc in 1989, [2] is marked by the inferior margin of V2 and superior margin of V3, from their origin to the entrance in the foramen rotundum and ovale, respectively. It is possible to expose ICA from its horizontal petrous portion and lateral loop to the ascending cavernous segment. ...
Background
The anatomy and surgical approach to the cavernous sinus and the middle fossa can constitute a considerable challenge, specially for young surgeons. Although their surgical explorations have gone through a popular phase in the past, to this date, they remain an uncomfortable subject for many neurosurgeons. The aim of this paper is to systematically review its anatomy and multiple corridors through a step-by-step dissection of the middle fossa triangles, providing a roadmap for surgeons.
Methods
A step-by-step dissection of the cavernous sinus was performed in two fresh-frozen cadavers aiming to describe the anatomy of ten different middle fossa triangles, demonstrating the feasibility of the use of their spaces while surgically approaching this area.
Results
The intradural opening of the roof of the cavernous sinus was obtained by dissection of clinoidal, carotid-oculomotor, supratrochlear, optic-carotideal, and oculomotor triangles, allowing an expanded superior view. On the counterpart, the extradural exploration of the lateral wall through the middle fossa floor peeling exposed the infratrochlear, anteromedial, and anterolateral triangles. The middle fossa floor itself was the door to approaching posterior fossa through anterior petrosectomy. The dissection of each individual triangle can be amplified exponentially with exploration of its adjacents, providing broader surgical corridors.
Conclusion
The cavernous sinus still remains far from an “every man’s land,” but its systematic study based on direct approaches can ease the challenges of its surgical exploration, allowing surgeons to feel more comfortable with its navigation, with consequently benefit in the treatment of patients.
... The oculomotor triangle (Hakuba´s triangle and medial triangle) is delimited by three dural folds forming the medial or interclinoid border, lateral or anterior petroclinoid border, and posterior, base, or posterior petroclinoid border. In addition to surrounding the entry point of the third cranial nerve to the roof of the cavernous sinus, it contains the horizontal portion of the intra-cavernous segment of the internal carotid artery (ICA) [5,6,10,14] (Figs. 1, 2, 4) ( Table 1). ...
... It contains in its anterior portion the optic strut, in its medial portion the clinoid segment of the ICA, and in its posterior segment the roof of the cavernous sinus. [5,6,9,10,15] (Figs. 1, 2, 3, 4, 5) ( Table 1). ...
... Through this triangle, we can find the posterior curvature of the intra-cavernous segment of the ICA and, in some cases, the exit of the meningohypophyseal trunk, the inferolateral trunk, and, less frequently, the medial curve of the ICA. [5,6,11,14,28] (Figs. 4, 5, 6) (Table 1). ...
Abstract
· ·
The middle fossa, cavernous sinus, and paraclival triangles consist of ten triangles. Their use in a surgical approach is vast; most are used as landmarks to access and identify other structures of surgical interest. Multiple labels, borders, and contents mentioned by different authors make understanding and reproduction challenging and confusing. This study aims to organize and clarify recent or most relevant publications and disclose our portrayal of the ten triangles using cadaveric dissection and simple and practical figures. Four middle fossa triangles, four cavernous sinus triangles, and two paraclival triangles were dissected and delineated in a cadaveric specimen. Drawings were simplified to eliminate confusion and evaluate the triangles effortlessly. Similarities and differences in triangle names, border limits, and contents are described in a precise form. The recognition of triangle landmarks allows for treating pathologies in a frequently distorted anatomy or challenging to access structure. That is why an accurate knowledge of the surgical anatomy should be mastered, and a safe approach should be accomplished.
... Understanding the anatomy of Hakuba's triangle is essential to the treatment of aneurysms, caroticocavernous fistulae and arteriovenous malformations that can arise from here. 50 Akira Hakuba (1934e2004) was the first to describe this segment of the cavernous sinus. He was a Japanese neurosurgeon, who graduated from Osaka University in 1962, where he later also started his neurosurgical practice. ...
Eponyms highlight the contributions made to medicine over the years, and celebrate individuals for their work involving diseases, pathologies, and anatomical landmarks. We have compiled an in-depth report of eponyms used in skull base neurosurgery, as well as the historical contexts of the personalities behind the names.
A literature search identified 36 eponyms of bones, foraminae and ligaments of the skull base named after anatomists and physician-scientists. The 36 eponymous structures pinpointed include Arnold’s canal, the foramen of Arnold, Bill’s bar, Bertin’s bones, Civinini’s canal, Civinini’s ligament, Civinini’s process, sinodural angle of Citelli, Clivus of Blumenbach, Dorello’s canal, the Eustachian tube, the eponymous cavernous sinus triangles of Parkinson, Kawase, Mullan, Dolenc, Glasscock and Hakuba, the Fallopian canal, the Glasserian fissure, Gruber’s ligament, Haller cells, the spine of Henle, Highmore’s antrum, the foramen of Huschke, Hyrtl’s fissure, the Ingrassia process, Jacobson’s canal, the MacEwen triangle, Meckel’s cave, the Onodi air cell, the Pacchionian foramen, Fossa of Rosenmuller, the foramen of Vesalius, the Vidian canal, Trautman’s triangle and the annular tendon of Zinn.
Knowledge of the relevant eponyms enables succinct descriptions of important skull base structures, provides an understanding of associated clinical implications, and reminds us of the vast history of contributions to neurosurgery made by prominent figures in the field.
... The carotid-oculomotor triangle is used for approaches to the basilar artery. 12,13 Oculomotor-Tentorial Triangle ...
Objective:
Anatomical triangles defined by intersecting neurovascular structures delineate surgical routes to pathological targets and guide neurosurgeons during dissection steps. Collections or systems of anatomical triangles have been integrated into skull base surgery to help surgeons navigate complex regions such as the cavernous sinus. The authors present a system of triangles specifically intended for resection of brainstem cavernous malformations (BSCMs). This system of triangles is complementary to the authors' BSCM taxonomy that defines dissection routes to these lesions.
Methods:
The anatomical triangle through which a BSCM was resected microsurgically was determined for the patients treated during a 23-year period who had both brain MRI and intraoperative photographs or videos available for review.
Results:
Of 183 patients who met the inclusion criteria, 50 had midbrain lesions (27%), 102 had pontine lesions (56%), and 31 had medullary lesions (17%). The craniotomies used to resect these BSCMs included the extended retrosigmoid (66 [36.1%]), midline suboccipital (46 [25.1%]), far lateral (30 [16.4%]), pterional/orbitozygomatic (17 [9.3%]), torcular (8 [4.4%]), and lateral suboccipital (8 [4.4%]) approaches. The anatomical triangles through which the BSCMs were most frequently resected were the interlobular (37 [20.2%]), vallecular (32 [17.5%]), vagoaccessory (30 [16.4%]), supracerebellar-infratrochlear (16 [8.7%]), subtonsillar (14 [7.7%]), oculomotor-tentorial (11 [6.0%]), infragalenic (8 [4.4%]), and supracerebellar-supratrochlear (8 [4.4%]) triangles. New but infrequently used triangles included the vertebrobasilar junctional (1 [0.5%]), supratrigeminal (3 [1.6%]), and infratrigeminal (5 [2.7%]) triangles. Overall, 15 BSCM subtypes were exposed through 6 craniotomies, and the approach was redirected to the BSCM by one of the 14 triangles paired with the BSCM subtype.
Conclusions:
A system of BSCM triangles, including 9 newly defined triangles, was introduced to guide dissection to these lesions. The use of an anatomical triangle better defines the pathway taken through the craniotomy to the lesion and refines the conceptualization of surgical approaches. The triangle concept and the BSCM triangle system increase the precision of dissection through subarachnoid corridors, enhance microsurgical execution, and potentially improve patient outcomes.