Comprehensive anatomical study of meningeal arteries in dromedaries.

This study provides a detailed, in-depth analysis of the anatomy, topography, and branching patterns of the meningeal arteries in dromedary camels, a subject that has not previously been thoroughly studied in animals, providing insight into the intricate biological adaptations that allow them to survive in harsh environments. By precisely examining 20 heads obtained from freshly slaughtered dromedaries, we revealed the origins and topologies of the rostral, middle, and caudal meningeal arteries using advanced casting techniques for precise rendering. Our findings indicate that the rostral meningeal artery derives from the external ethmoidal artery and primarily supplies the rostrodorsal region of the frontal lobe. The middle meningeal artery provides blood to approximately two-thirds of the brain meninges. The caudal meningeal artery is derived from the occipital artery and supplies the meninges covering the cerebellum, caudal part of the falx cerebri, and tentorium cerebelli. Significantly, our study revealed the presence of accessory branches originating from the rostral epidural rete mirabile, a finding not previously described in the existing literature. These branches supply the meninges of the frontal and lateral regions of the frontal lobes. This novel study advances our understanding of the meningeal arteries in dromedaries and has significant implications for advancements in veterinary neuroscience.

The petrosal artery and its variations: a comprehensive review and anatomical study with application to skull base surgery and neurointerventional procedures.

BACKGROUND: The petrosal artery supplies several structures at the skull base and is often the focus of various neurointerventional procedures. Therefore, knowledge of its anatomy and variations is important to surgeons and interventionalists. MATERIALS AND METHODS: Twenty latex injected cadaveric heads (40 sides) underwent microsurgical dissection of the petrosal artery. Documentation of the course of the artery and its branches were made. Measurements of the petrosal artery's length and diameter were performed using microcallipers. RESULTS: A petrosal artery was identified on all sides. The mean length and diameter of the artery within the middle cranial fossa was 2.4 cm and 0.38 mm, respectively. Branches included the following: dural, ganglionic, V3 branches, branches extending through the foramen ovale, branches directly to the greater petrosal and lesser petrosal nerves, branches to the floor of the hiatus of the greater and lesser petrosal nerves, branch to the arcuate eminence, and superior tympanic artery. No statistically significant differences were noted between male and female specimens, but right-sided petrosal arteries were in general, larger in diameter than left sides. CONCLUSIONS: A thorough anatomical knowledge of the petrosal artery and to its relationship to the facial nerve and other neurovascular structures is necessary to facilitate effective endovascular treatment and to preclude facial nerve complications.

Anatomy of the Middle Meningeal Artery

Introduction The middle meningeal artery (MMA) is an important artery in neurosurgery. As the largest branch of the maxillary artery, it provides nutrition to the meninges and to the frontal and parietal regions. Diseases, including dural arteriovenous fistula (DAVF), pseudoaneurysm, true aneurysm, traumatic arteriovenous fistula (TAVF), Moya-Moya disease (MMD), recurrent chronic subdural hematoma (CSDH), migraine, and meningioma,may be related to the MMA. The aim of the present study is to describe the anatomy of the MMA and to correlate it with brain diseases. Methods A literature review was performed using the PubMed, Scielo, Scientific Direct, Ebsco, LILACS, TripDataBase and Cochrane databases, with the following descriptors: neurosurgery, neuroanatomy, meninges and blood supply. Discussion The MMA is embedded in a cranial groove, and traumatic or iatrogenic factors can result in MMA-associated pseudoaneurysms or arteriovenous fistulas (AVFs). In hemodynamic stress, true aneurysms can develop. Arteriovenous fistulas, pseudoaneurysms, and true aneurysms can be effectively treated by endovascular or surgical removal. In MMD, the MMA plays a role in the development and in the improvement of collateral circulation. Finally, in cases of CSDH, when standard surgery and drainage fail, MMA embolization can constitute a great alternative. Conclusion The MMA is a relevant structure for the understanding of neurosurgical diseases. In conclusion, every neurosurgeon must know the anatomy of the MMA sufficiently to correlate it with the diagnosed pathology, thus obtaining treatment effectiveness and preventing brain lesion.

Anatomy of the Dorsal Meningeal Artery Including Its Variations: Application to Skull Base Surgery and Diagnostic and Interventional Imaging.

BACKGROUND: The blood supply to the skull base is important to surgeons and those performing interventional and diagnostic procedures in this region. However, 1 vessel with a vast distribution in this area, the dorsal meningeal artery (DMA), has had few anatomic studies performed to investigate not only its normal anatomy but also its variations. Therefore the current study aimed to analyze the DMA via cadaveric dissection. METHODS: In 10 adults, latex-injected, cadaveric heads (20 sides), the DMA was dissected using a surgical microscope. This artery and its branches were documented and measured. RESULTS: A DMA was identified on all sides. In the majority (85%), it was a branch of the meningohypophysial trunk or common stem with either the inferior hypophysial or tentorial arteries and always had branches that traversed the basilar venous plexus. Multiple branches of the DMA were identified and categorized as bony, dural, neural, and vascular. CONCLUSIONS: Surgeons operating at the skull base or clinicians interpreting imaging of this area should have a good working knowledge of the DMA and its typical and variant anatomy.

Bone bridges in the groove for middle meningeal artery / Puentes óseos en el surco para la arteria meníngea media

SUMMARY: The middle meningeal artery is an important vessel that is distributed in the endocranium region, between greater wing of sphenoid by the homonymous groove. There are few references on the formation of bone bridges in their trajectory, an aspect of relevance in morphology. The present study included 100 skulls -dried and whole heads- of adults, removing the calvaria, and identifying the spinous foramen, through which the middle meningeal artery courses to determine the existence or not of bone bridges -unilateral, bilateral or absence- for the passage of this artery. Of 100 adult skulls analyzed, it was found at the level of the medial aspect of the greater wing of the sphenoid bone and in its internal table, 73 % presented it and in 27 % there was absence. Of the specimens with bone bridges, 39 % were bilateral and of the latter, 34 % was unilateral and 16 % was on the right and 18 % on the left. The bony bridge for the middle meningeal artery is an anatomical constant that must be evaluated in anatomical, clinical and surgical considerations.

RESUMEN: La arteria meníngea media se distribuye en la región del endocráneo entre el ala mayor del esfenoides por el surco para dicha arteria. Existen pocas referencias sobre la formación de puentes óseos en su trayectoria, aspecto de relevancia en el campo morfológico. El presente estudio incluyó 100 cráneos -secos y cabezas enteras- de adultos, a los que se les extirpó la calvaria e identificó el foramen espinoso, por donde discurre la arteria meníngea media, para determinar la existencia o no de puentes óseos -unilaterales, bilaterales o ausenciaen su interior. De 100 cráneos adultos analizados, se encontró puentes óseos a nivel de la lámina medial del ala mayor del hueso esfenoides y en su tabla interna en un 73 % y en el 27 % no hubo. De las piezas con puentes óseos, el 39 % eran bilaterales y el 34 % eran unilaterales; el 16 % a la derecha y el 18 % a la izquierda. El puente óseo de la arteria meníngea media es una constante anatómica que debe ser evaluada en consideraciones anatómicas, clínicas y quirúrgicas.

Neuroanatomy of cranial dural vessels: implications for subdural hematoma embolization.

Adoption of middle meningeal artery embolization in the management of chronic subdural hematomas has led to a renewed interest in dural vascular anatomy. The readily identifiable major dural arteries and potential hazards associated with their embolization are well described. Less emphasized are several levels of intrinsic dural angioarchitecture, despite their more direct relationship to dural based diseases, such as subdural hematoma and dural fistula. Fortunately, microvascular aspects of dural anatomy, previously limited to ex vivo investigations, are becoming increasingly accessible to in vivo visualization, setting the stage for synthesis of the old and the new, and providing a rationale for the endovascular approach to subdural collections in particular. In contrast with traditional anatomical didactics, where descriptions advance from larger trunks to smaller pedicles, we present a strategic approach that proceeds from a fundamental understanding of the dural microvasculature and its relationship to larger vessels.

Surgical occlusion of middle meningeal artery in treatment of chronic subdural haematoma: anatomical and technical considerations.

BACKGROUND: The primary aim of chronic subdural haematoma (CSDH) treatment is to relieve pressure to improve neurological symptoms. The secondary aim is to avoid recurrence. The blood supply from the middle meningeal artery (MMA) to the haematoma membranes has recently become a research target, to enhance our understanding of the processes leading to growth and re-growth of a CSDH. Several studies indicate that endovascular embolization of the MMA (eMMA) reduces recurrence rates, but this effect must be confirmed in a randomized controlled setting. Endovascular embolization is an advanced and costly procedure carrying a significant risk of embolism in the elderly. The aim of this study was to assess anatomical and technical aspects of surgical occlusion of the MMA (soMMA) via a single same-procedure burr hole, as an alternative to eMMA. METHOD: Technical aspects of soMMA were assessed using cadaver head dissection. MMA anatomy was examined by mapping the branching pattern and distribution of MMA in dry skulls, and CSDH position was investigated by analysis of computed tomography (CT) of CSDHs. Finally, we evaluated the possibility of CT-guided navigation to mark the branching point of the anterior MMA division on the skin. RESULTS: We established anatomical landmarks to locate the MMA and found that particularly the anterior MMA branch can be occluded through a single burr hole at the pterion during the same procedure as haematoma decompression. CT of 1454 CSDHs in 1162 patients showed that the CSDH was anteriorly located in 57.5% compared with posteriorly in only 3%. This correlated with the anterior branch of the MMA being dominant in 58% of dry skull samples examined. We further confirmed that the MMA can be localized by neuronavigation as an alternative to using anatomical landmarks and average measurements. CONCLUSION: A CSDH is mainly anteriorly located and supposedly primarily supplied by the anterior MMA branch. In a simulated setting, soMMA can be performed during the same procedure as haematoma decompression. A few reservations notwithstanding, we find that soMMA may be a viable alternative to eMMA in most CSDH cases and that soMMA should be further evaluated in a clinical setting.

Temporalis muscle vasculature directly derived of the middle meningeal artery: a case report and review.

Pedicled temporalis muscular flap is a common procedure nowadays in reconstructive head and neck surgery, especially for oral or orbital cavity defects. We present a case of temporalis muscle and skull base dissection of a seventy-year-old fresh female cadaver with single temporal muscle vessels directly derived of the middle meningeal artery throughout the calvaria, therefore jeopardizing the harvest of the flap, which has never been described to our knowledge. Such a variation must be known of the reconstructive surgeon to plan the ideal reconstruction procedure.

Sphenoidal artery: review of the literature and analysis of a dissected arterially injected fetal orbit.

PURPOSE: The sphenoidal artery is considered a component of the complex and dangerous arterial anastomoses of the human orbitocranial region, particularly with the advent of interventional neuroimaging. The objective of this publication was to analyze the various descriptions of the sphenoidal artery in the literature as related to relevant photographs of a dissected arterially injected fetal middle cranial fossa and orbit. METHODS: Publications dealing with middle meningeal-ophthalmic arterial anastomoses, focusing on the sphenoidal artery, were reviewed. A relevant dissection of a fetal specimen was analyzed. RESULTS: The literature dealing with the sphenoidal artery is at times not in agreement. The nomenclature and anatomy of its passage through the superior orbital fissure or Hyrtl canal have variable descriptions. Photographs of the skull base of a dissected arterially injected fetal specimen show bilateral prominent orbital branches of the middle meningeal arteries. These branches entered both orbits in a course similar to the diagrammatic representations of the sphenoidal artery, and give rise to several major intraorbital arteries. This study provides the only photographic image in the literature of this variation in a human fetal anatomic dissection. CONCLUSIONS: Review of the literature dealing with the sphenoidal artery shows inconsistent nomenclature and conflicting descriptions of its anastomotic connections, and varying evolutionary and embryologic theories. Analysis of the dissected fetal skull base indicates that the sphenoidal artery is not a distinct artery but just a middle meningeal orbital arterial branch, an important component of the complex and dangerous arterial anastomoses of the human orbitocranial region.

Clinical implications in orbital and pterional flap surgeries as well as radioimaging studies to determine topographical prevalence and characterization of meningo-orbital foramen in orbits of the Indian population / Implicaciones clínicas en cirugías de colgajo orbitario y pterional, así como estudios de radioimagen para determinar la prevalencia topográfica y la caracterización del foramen meningoorbitario en órbitas de la población india

SUMMARY: The pear-shaped bony orbit connects with intracranial cavity via foramina's and fissures. The Meningo-orbital Foramen (MOF) is usually present in greater wing of sphenoid close to lateral edge of Superior orbital fissure. It provides a route for an anastomosis between the orbital branch of the middle meningeal artery (MMA) and recurrent meningeal branch of Ophthalmic Artery (OA) and hence, risk of damage during surgeries can occur. To verify occurrence and location, with morphology of MOF in dry orbits and the impending clinical hazards in surgeries pertaining to the orbit, document and analysis it to determine a standardized guideline. The presence for MOF was studied in 446 dry orbits with its location from the supra orbital margin (SOM), front zygomatic suture (FZS), the lateral tubercle of Whitnall (WT)and the lateral end of superior orbital fissure (SOF) along with its patency, laterality and number of foramina's present. Nylon probes, long divider/pins, compass and Vernier callipers was used to check the patency and various parameters. The study noted the percentage prevalence of MOF as 69 % with communication with middle cranial fossa (MCF) being 76 % of 69 % and the average distance from SOM, FZS, WT and lateral end of SOF being 35.58 mm, 24.9 mm, 26.6 mm and 0.92 mm. On comparison with various population studies, certain similarities and differences with regards to different parameters were noted. Prevalence of MOF was mostly unilateral and showed multiple foramina, that can act as channels for arteries, a variant of MMA or OA, that supply orbital structures or tumour growths. Thus, awareness of this variation is of prime importance to ophthalmologists and neurosurgeons as well as interventional radiologists, in preventing haemorrhagic condition which could further raise the difficulties in operative procedures and surgical outcomes.

RESUMEN: La órbita ósea en forma de pera se conecta con la cavidad intracraneal a través de forámenes y fisuras. El foramen meningoorbitario (MOF) suele estar presente en el ala mayor del esfenoides cerca del margen lateral de la fisura orbitaria superior. Proporciona una ruta para una anastomosis entre la rama orbitaria de la arteria meníngea media (MMA) y la rama meníngea recurrente de la arteria oftálmica (OA) y, por lo tanto, puede ocurrir riesgo de daño durante las cirugías. Para verificar la ocurrencia y ubicación, con la morfología de MOF en órbitas secas y los peligros clínicos inminentes en cirugías de la órbita, documentarlo y analizarlo para determinar una pauta estandarizada. Se estudió la presencia de MOF en 446 órbitas secas desde el margen supraorbitario (MOS), sutura cigomática frontal (FZS), el tubér- culo lateral de Whitnall (WT) y el extremo lateral de la fisura orbitaria superior (SOF) junto con su permeabilidad, lateralidad y número de forámenes presentes. Se utilizaron sondas de nailon, divisores / pasadores largos, brújula y calibradores Vernier para comprobar la permeabilidad. En el estudio se pudo observar que la prevalencia porcentual de MOF era del 69 %, siendo la comunica- ción con la fosa craneal media (MCF) del 76 % del 69 % y la distancia promedio desde SOM, FZS, WT y el extremo lateral de SOF era de 35,58 mm, 24,9 mm, 26,6 mm y 0,92 mm. En comparación con varios estudios de población, se observaron ciertas similitudes y diferencias con respecto a diferentes parámetros. La prevalencia de MOF fue mayoritariamente unilateral y mostró múltiples forámenes, que pueden actuar como canales para las arterias, una variante de MMA u OA, que irrigan estructuras orbitarias o crecimientos tumorales. Por lo tanto, la conciencia de esta variación es de primordial importancia para los oftalmólogos y neurocirujanos, así como para los radiólogos intervencionistas, en la prevención de una enfermedad hemorrágica que podría aumentar aún más las dificultades en los procedimientos y los resultados quirúrgicos.

Evaluation of the anastomoses between the ophthalmic artery and the middle meningeal artery by superselective angiography.

PURPOSE: There are three anastomoses between the ophthalmic artery (OA) and the middle meningeal artery (MMA): the anastomotic branch with MMA, the recurrent meningeal branch and the anterior falx artery. We aimed to evaluate the anastomotic branches between the OA and the MMA on superselective angiograms of pediatric patients with retinoblastoma. MATERIALS AND METHODS: We evaluated 126 angiographies performed on children with retinoblastoma. The mean diameter and angiographic visibility percentage of the anastomotic branches between the OA and the MMA were examined according to age group and sex. RESULTS: The mean diameter of anastomotic branch with MMA was measured 0.58 ± 0.13 mm and we found this branch in 15 of 126 angiographic images (11.9%). We detected the recurrent meningeal branch in 47 of total images (37.3%). The recurrent meningeal branch arose 85.1% from the lacrimal artery, 8.5% from the anastomotic branch with MMA and 6.4% directly from the OA. The mean diameter of this artery was measured 0.21 ± 0.06 mm. Anterior falx artery was found in 86 of 126 angiographic peocedures (68.3%) and the mean diameter was measured 0.22 ± 0.06 mm. CONCLUSION: Knowledge of the anastomoses between the OA and the MMA system are all necessary to perform safe and successful endovascular and surgical procedures involving the orbital region.

High frequency of ophthalmic origin of the middle meningeal artery in chronic subdural hematoma.

PURPOSE: Embolization of middle meningeal artery (MMA) has been proposed for postoperative recurrences and primary treatment of chronic subdural hematoma (CSDH). This endovascular intervention is safe only when MMA originates from the internal maxillary artery. The aim of this study was to report an unusual high frequency of MMA originating from the ophthalmic artery, which prohibits this treatment. METHODS: In this retrospective study, we reviewed the anatomical origin of the MMA in patients with CSDH who were referred to our center for endovascular treatment between January 2017 and May 2019 (42 patients with 58 CSDH). We compared the prevalence of this variant in a control group of 66 patients who underwent embolization for epistaxis during the same period. RESULTS: In CSDH group, MMA originated from the ophthalmic artery in 8 out of 58 internal carotid arteries (13.8%). In the control group, this variant was observed in only 1 case out of 131 internal carotid arteries (0.7%) (OR = 20; 95% CI 2.6 to 925.2, p = 0.0003). CONCLUSION: In this study, we report an extremely high prevalence of MMA originating from the ophthalmic artery in CSDH. In the hypothesis of prospective studies, a priori recognition of this variant will be necessary in order to exclude patients in whom endovascular treatment will not be feasible.

Dural arteries of the dorsoclival area.

OBJECTIVE: In the literature, there is a lack of complete description of dural arteries of the dorsoclival area with contradictory data. However, dorsoclival area is a site of tumors and vascular malformation or the skull base. That is why, the knowledge of dural arteries is very important. METHODS: Using a colored silicone mix preparation, fifteen sides of eight cranial bases were studied using 4-20× magnification of the surgical microscope. RESULTS: Dorsoclival area is supplying by three arterial complexes, internal carotid artery complex with always the dorsal meningeal artery for the superior two-third of the clivus, medial clival artery for the dorsum sellae, the external carotid artery complex with the hypoglossal and jugular branches of the ascending pharyngeal artery for the inferior one-third of the clivus, and the vertebral artery complex with the anterior meningeal artery for the most inferior part of the clivus and the anterior edge of the foramen magnum. Moreover, there are many anastomoses between those three arterial complexes at this area. CONCLUSION: Dural arterial supply of the dorsoclival area is very opulent. Its knowledge is important for surgical approaches and endovascular procedures.

Characterization of Anatomical Landmarks for Exposing the Internal Carotid Artery in the Infratemporal Fossa Through an Endoscopic Transmasticator Approach: A Morphometric Cadaveric Study.

BACKGROUND: The Eustachian tube and sphenoid spine have been previously described as landmarks for endonasal surgical identification of the most distal segment of the parapharyngeal internal carotid artery (PhICA). However, the intervening space between the sphenoid spine and PhICA allows for error during exposure of the artery. In the present study, we have characterized endoscopic endonasal transmasticator exposure of the PhICA using the sphenoid spine, vaginal process of the tympanic bone, and the "tympanic crest" as useful anatomical landmarks. METHODS: Endonasal dissection was performed in 13 embalmed latex-injected cadaveric specimens. Two open lateral dissections and osteologic analysis of 10 dry skulls were also performed. RESULTS: A novel and palpable bony landmark, the inferomedial edge of the tympanic bone, referred to as the tympanic crest, was identified, leading from the sphenoid spine to the lateral carotid canal. Additionally, the vaginal process of the tympanic bone, viewed endoscopically, was a guide to the PhICA. The sphenoid spine was bifurcate in 20% of the skulls, with an average length of 5.98 mm (range, 3.9-8.2 mm), width of 5.81 mm (range, 3.0-10.6 mm), and distance to the carotid canal of 4.48 mm (range, 2.5-6.1 mm). CONCLUSION: The sphenoid spine and pericarotid space has variable anatomy. Using an endoscopic transmasticator approach to the infratemporal fossa, we found that the closest landmarks leading to the PhICA were the tympanic crest, sphenoid spine, and vaginal process of the tympanic bone.

Ultrasonographic assessment of the maxillary artery and middle meningeal artery in the infratemporal fossa.

PURPOSE: To investigate with Doppler ultrasonography the maxillary and middle meningeal arteries in the infratemporal fossa, and describe their hemodynamic characteristics. METHODS: We included 24 female and 11 male volunteers without vascular diseases, with a median age of 43 years. We used the acoustic window, enlarged by subjects half-opening their mouth, located below the zygomatic arch, in front of temporo-mandibular joint, to reach the maxillary and middle meningeal arteries. RESULTS: In the 35 subjects, 112 arteries were visualized successfully: 60 maxillary (85.7%), and 52 middle meningeal arteries (74.3%), at a depth of 2.40 and 2.50 cm, respectively. Their blood flow was directed anteriorly and away from the probe. While all the measured hemodynamic characteristics differed significantly between the maxillary and the middle meningeal artery (P < 0.001), there was no significant difference between male and female subjects, nor between the left or the right side. CONCLUSIONS: The maxillary and middle meningeal arteries can be insonated in the infratemporal fossa through the easily accessible acoustic window below the zygomatic arch, when the patient holds his mouth half open. They can be differentiated by their ultrasonographic characteristics and blood flow features.

Tonic regulation of middle meningeal artery diameter by ATP-sensitive potassium channels.

Activation of ATP-sensitive potassium (KATP) channels in arterial smooth muscle (ASM) contributes to vasodilation evoked by a variety of endogenous and exogenous compounds. Although controversial, activation of KATP channels by neuropeptides such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase activating peptide (PACAP) in the trigeminovascular system, including the middle meningeal artery (MMA), has been linked to migraine headache. The objective of the current study was to determine if ongoing KATP channel activity also influences MMA diameter. In the absence of other exogenous compounds, the KATP channel inhibitors glibenclamide and PNU37883A induced constriction of isolated and pressurized MMAs. In contrast, KATP channel inhibition did not alter cerebral artery diameter. Consistent with tonic KATP activity in MMA, glibenclamide also induced ASM membrane potential depolarization and increased cytosolic Ca2+. Inhibitors of cAMP-dependent protein kinase (PKA) abolished basal KATP activation in MMA and caused a marked decrease in sensitivity to the synthetic KATP channel opener, cromakalim. In vivo MMA constriction in response to gibenclamide was observed using two-photon imaging of arterial diameter. Together these results indicate that PKA-mediated tonic KATP channel activity contributes to the regulation of MMA diameter.

Trifurcated external carotid artery and complete gamma-loop of its maxillary branch.

The external carotid artery (ECA) normally bifurcates terminally with the superficial temporal artery (STA) and the maxillary artery (MA). From the horizontally coursing, mandibular segment of the MA leaves the middle meningeal artery (MMA). We hereby report a previously unknown anatomic possibility, incidentally found during an angio-CT scan in an adult female patient. Unilaterally, the ECA was terminally trifurcated, sending off the MA, STA, and MMA. On that side, the mandibular segment of the MA had a gamma-loop and the contralateral one had a U-loop; both these loops were inferior to the lateral pterygoid muscle, closely approaching the respective lingula of the mandible. These findings are relevant during surgery of the parotid gland and infratemporal fossa, approaches of the MMA, and inferior alveolar nerve blocks. The modified origin of the MMA could be explained by an altered development of the primitive stapedial artery.

Posterior Meningeal Artery Origin Patterns among 300 Cases and Their Clinical Importance.

BACKGROUND AND PURPOSE: The posterior meningeal artery (PMA) is known as a dura mater-nourishing vessel. We encountered a patient with Wallenberg syndrome during transarterial embolization of the PMA associated with the dural arteriovenous fistula (DAVF). METHODS: After development of Wallenberg syndrome in the patient, we assessed origins of the PMA patterns in 300 cases and divided them into 3 types. CASE PRESENTATION: A 63-year-old man was incidentally diagnosed as having transverse-sigmoid sinus DAVF with a cortical venous reflux. During the transarterial embolization, the patient complained of vertigo and numbness of the right extremities. Postoperatively, the patient exhibited Wallenberg syndrome. Diffusion-weighted magnetic resonance imaging showed a high-intensity area on the lateral side of the right medulla. CONCLUSIONS: While performing arterial embolization of the PMA that directly originates from the intracranial vertebral artery, the possibility of deficient brainstem nourishment must be considered.

Unusual origin and relations of the accessory meningeal artery: a case report / Origen inusual y relaciones de la arteria meníngea accesoria: reporte de un caso

SUMMARY: Accessory meningeal artery is a branch of the first part of the maxillary artery. It supplies the structures in the infratemporal fossa and the dura mater in the middle cranial fossa. Accessory meningeal artery arose from the middle meningeal artery, 25 mm below the base of the skull and entered the middle cranial fossa through the foramen ovale. The two roots of the auriculotemporal nerve looped around it. The knowledge of the variant origin and relations may be useful during the surgeries of the infratemporal fossa. It might also be useful to the radiologists.

RESUMEN: La arteria meníngea media es una rama accesoria que emerge al inicio de la arteria maxilar. Suministra la vascularización a nivel de la fosa infratemporal y la duramadre en la fosa craneal media. En este trabajo, surgió una arteria meníngea accesoria de la arteria meníngea media, a una 25 mm por debajo de la base del cráneo, accediendo en la fosa craneal media a través del foramen oval. Las dos raíces del nervio auriculotemporal la rodeaban. El conocimiento de esta variación y sus relaciones pueden ser útiles durante las cirugías de la fosa infratemporal, como así también puede ser útil para los radiólogos.

Intracranial Bony Canal of the Middle Meningeal Artery - Morphological and Histological Analysis.

The middle meningeal artery (MMA) can play an important role in the surgical revascularization. However, the MMA can be easily injured if it passes through a bony canal. We investigated the morphological and histological features of the bony canal to improve surgical results. MATERIALS AND METHODS: Fifty adult dry skulls were investigated. The length of the bony canal and the distance from the orbital rim to the bony canal were measured. Additionally, 28 cadaveric heads were examined histologically. RESULTS: Sixty-three bony canals were found in 43 skulls. The mean length of bony canals was 9.2 mm, and the mean distance from the orbital rim was 24.0 mm. The bony canal ran mainly from the sphenoid bone (69.8%) to the parietal bone (73.0%). Histologically, both sides of the meningeal grooves gradually closed the distance, and formed the bony canal. The MMA inside the bony canal was enveloped with collagen tissues, divided into branches, and was accompanied by the vein. CONCLUSIONS: The bony canal is located around the pterion and is formed during bone growth. The MMA is covered with collagen tissues inside the bony canal. It is possible to safely expose and preserve the MMA during craniotomy with careful drilling.