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.

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.

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.

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.

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.

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.

Foramen meningo orbitario / Meningo orbital foramen

El foramen meningo orbitario (FMO), ubicado en el ala mayor del esfenoides y cercano al extremo lateral de la fisura orbitaria superior (FOS), comunica órbita con fosa craneal media, permitiendo el paso de una anastomosis entre las arterias oftálmica y meníngea media. Su prevalencia varía del 6 al 82,9 % y puede presentarse en forma unilateral o bilateral, único o múltiple y de forma circular, ovoidal o de ranura. Nuestro objetivo fue evidenciar la presencia del FMO, describiendo sus características morfológicas, en cráneos secos de individuos adultos chilenos de ambos sexos. Se utilizaron 54 cráneos con ambas órbitas. Se consideró; presencia, unilateralidad o bilateralidad, cantidad de forámenes por órbita, forma, ubicación en relación al plano horizontal determinado por el extremo lateral de la FOS, distancia al extremo lateral de la FOS, diámetro y diferencias sexuales. Las mediciones se realizaron con sonda de nylon, compás de puntas secas y cáliper digital. Un 46,29 % de la muestra presentó FMO, con mayor presencia en individuos femeninos. En un 28 % se presentó unilateral y en un 72 % bilateral. Predominó la forma circular (79,07 %) sobre la ovoidal (18 %) y sobre la forma de ranura (2,33 %). El FMO se observó en un 90,69 % sobre el plano horizontal que determina el extremo lateral de la FOS y en un 9,31 % en el mismo plano. La distancia del FMO al extremo lateral de la FOS fue de 6,58 mm y el diámetro del FMO correspondió a 1,22 mm. Nuestros resultados coinciden con la literatura, respecto a su presencia, a la comunicación que permite, a su ubicación, a su forma y tamaño. Se pudo constatar semejanzas y algunas diferencias menores con cráneos indios, asiáticos y pakistaníes. También pudimos evidenciar diferencias por sexo. El conocimiento acabado del FMO tiene importancia en anatomía, antropología, oftalmología, traumatología, imagenología, cirugía e identificación humana.

The meningo orbital foramen (MOF) is located in the major wing of the sphenoid and near the lateral end of the superior orbital fissure (SOF), communicating orbit with the middle cranial fossa and allowing the passage of an anastomosis between the ophthalmic and middle meningeal arteries. Its prevalence varies from 6 to 82.9 % and may occur unilaterally or bilaterally, single or multiple, and may have a circular, ovoid or groove form. The aim of this study is to evidence the existence of MOF, describing its morphological characteristics in dry skulls of Chilean adults of both sexes. The present study analyzed 54 skulls containing both orbits, considering the following criteria: Existence, unilaterality or bilaterality, number of foramens by orbit, shape, location in relation to the horizontalbaselinedetermined by the lateral end of the SOF, distance to the lateral end of the SOF and diameter and variations by sex. Measurements were made with nylonprobe,compass dry point and digital caliper. Of the sample, 46.29 % presented MOF with a greater prevalence in female samples. In 28 % of the cases it was unilateral and in the other 72 % bilateral. The circular shape was predominant in 79.07 %, followed by the ovoidal 18 % and thegrooveform 2.33 %. The MOF was observed in 90.69 % on the horizontalbaselinethat determines the lateral end of the SOF and in 9.31 % in the samebaseline. The average distance from the MOF to the lateral end of the SOF was 6.58 mm and the diameter of the MOF corresponded to 1.22 mm. Our results are consistentwith similar studies. There were some minor differences observed in Indian, Asian andPakistani skulls as well as some anatomical differences by sex. A better understanding of MOF plays an important role in anatomy, anthropology, ophthalmology, traumatology, medical imaging, surgery and human identification.

Surgical anatomy and preservation of the middle meningeal artery during bypass surgery for moyamoya disease.

BACKGROUND: The middle meningeal artery (MMA) is known to function as one of the important collateral routes in moyamoya disease. However, the anterior branch frequently courses within the lesser wing of the sphenoid bone and can easily be damaged during craniotomy for bypass surgery. This prospective study aimed to study the surgical anatomy of the MMA and to establish the technique to preserve it during bypass surgery for moyamoya disease. METHODS: Twenty-two patients with moyamoya disease underwent STA-MCA anastomosis combined with indirect bypass on 27 sides. The anatomical relationship between the anterior branch of the MMA and lesser wing was classified into three types: the bridge, monorail, and tunnel types. During surgery, the lesser wing was carefully resected with a rongeur or high-speed diamond drill to preserve the anterior branch of the MMA. RESULTS: The anterior branch of the MMA was classified into the bridge type in 5 sides (18.5 %), monorail type in 10 sides (37.0 %), and tunnel type in 12 sides (44.5 %). Patient age was closely related to the anatomical findings (χ (2) test, p = 0.0168). Careful resection of the lesser wing with a rongeur could preserve bridge- and monorail-type MMAs (100 and 71.4 %, respectively). However, drilling out of the lesser wing under a surgical microscope was essential to preserve the tunnel-type MMA. Intraoperative indocyanine green videoangiography was useful to confirm patency during surgery. CONCLUSIONS: It is essential to understand the surgical anatomy of the MMA around the pterion in order to preserve its anterior branch during bypass surgery for moyamoya disease.

Anatomic study of the distance between the articular eminence and foramen spinosum and foramen spinosum and petrotympanic fissure.

PURPOSE: The middle meningeal artery is in close proximity to the medial aspect of the temporomandibular joint (TMJ). A major potential complication of surgery in the area of the TMJ is possible severance of the middle meningeal artery. An understanding of the relationship of the middle meningeal artery to easily identifiable landmarks lateral to the TMJ can help prevent the complications associated with TMJ surgery. The aim of the present study was to define the location of the middle meningeal artery by relating the distance between the easily identifiable bony landmarks of the articular eminence, petrotympanic fissure, and foramen spinosum. MATERIALS AND METHODS: Using a cross-sectional study design, we selected dried skulls from the Hamman-Todd skeleton collection at the Cleveland Museum of Natural History that were older than 20 years of age at death. The primary study variables were the distances between the articular eminence and foramen spinosum and the foramen spinosum and petrotympanic fissure. To appropriately analyze the variables, stratifications of age, gender, race, and anatomic location were applied. To measure the relationship between the stratifications and distances, a multivariate analysis of variance test was performed. The statistical results were deemed significant at P < .05. RESULTS: The sample consisted of 354 skulls or a total of 708 complexes. In analyzing the data, we noted that the only stratifications that bore any statistical significance were gender, with P < .0001, and the race-distance correlation, with a P value of .0007. CONCLUSIONS: The results of the present study suggest a definite difference in regard to gender on the distance between both sets of anatomic landmarks. Future studies could be tailored to further explore the effect of age on the distance, as a slight correlation was noted in our study.

Navigational area of the cranio-orbital foramen and its significance in orbital surgery.

The cranio-orbital foramen (COF) is located on the lateral wall of the orbit. It is a potential source of hemorrhage during deep lateral orbital dissection, since it functions as an anastomosis between the lacrimal artery and the middle meningeal artery. The aim of this study was to guide and facilitate the surgical procedures in the orbit, so as to determine a navigational area and the precise location of the COF and to standardize certain anatomical marks. The navigational area of the COF and topographical features were studied in 75 craniums with presented COF. 33 bilateral main COFs, 41 (18 on the right, 23 on the left) unilateral main COFs at the main cranium and 19 accessory COFs were studied for their navigational features on the orbit. The distances between the COF and the fronto-zygomatic suture, supraorbital notch, lateral angle of the superior orbital fissure (SOF) and Whitnall's tubercle were measured. The mean distance of the COF from the fronto-zygomatic suture, supraorbital notch, lateral angle of the SOF and Whitnall's tubercle was 26.3, 37.3, 92 and 27.1 mm, respectively. For the navigational area signs of the COF, areas of the orbit that form the transversal and vertical lines are generated on the reference points. Whilst the upper outer area of the orbit contains a potential bleeding risk, the bottom section of the outer column is identified as safe for the surgical operations of the lateral orbital wall. The fronto-zygomatic suture and Whitnall's tubercle are recommended as the most reliable navigational landmarks for identifying the COF. Hence, the transversal and vertical orientation of the COF should be mastered by the surgeons reconstructing the anterior base of the skull and the orbit.

A 3-dimensional transnasal endoscopic journey through the paranasal sinuses and adjacent skull base: a practical and surgery-oriented perspective.

An endoscopic approach through the transnasal corridor is currently the treatment of choice in the management of benign sinonasal tumors, cerebrospinal fluid leaks, and pituitary lesions. Moreover, this approach can be considered a valid option in the management of selected sinonasal malignancies extending to the skull base, midline meningiomas, parasellar lesions such as craniopharyngioma and Rathke cleft cyst, and clival lesions such as chordoma and ecchordosis. Over the past decade, strict cooperation between otorhinolaryngologists and neurosurgeons and acquired surgical skills, together with high-definition cameras, dedicated instrumentation, and navigation systems, have made it possible to broaden the indications of endoscopic surgery. Despite these improvements, depth perception, as provided by the use of a microscope, was still lacking with this technology. The aim of the present project is to reveal new perspectives in the endoscopic perception of the sinonasal complex and skull base thanks to 3-dimensional endoscopes, which are well suited to access and explore the endonasal corridor. In the anatomic dissection herein, this innovative device came across with sophisticated and long-established fresh cadaver preparation provided by one of the most prestigious universities of Europe. The final product is a 3-dimensional journey starting from the nasal cavity, reaching the anterior, middle, and posterior cranial fossae, passing through the ethmoidal complex, paranasal sinuses, and skull base. Anatomic landmarks, critical areas, and tips and tricks to safely dissect delicate anatomic structures are addressed through audio comments, figures, and their captions.

Origins of the middle meningeal artery and its probableembryological mechanism: a review

The middle meningeal artery is traditionally described by the human anatomy books as having its origin inthe first portion of the maxillary artery. However, more detailed studies have shown that there are numerousvariations on this arterial segment with considerable clinical importance. Therefore, the aim of this study wasto perform a wide review about this aspect analyzing scientific articles and textbooks. Thus, this review shallbe useful for clinicians, surgeons and academics that manipulate and keep interest for this particular anatomicalsite.

Clinical significance of maxillary artery and its branches: a cadaver study and review of the literature / Significado clínico de la arteria maxilar y sus ramas: un estudio en cadáver y la revisión de la literatura

The aim of this study was to investigate the anatomy of the maxillary artery (MA) and its branches. Fourteen sides of Turkish adult cadavers were dissected. The specimens were classified according to the relation between MA and the lateral pterygoid. After the removal of the lateral pterygoid, parts and branches of MA were exposed. We classified the branching patterns of MA in the pterygopalatine fossa. The calibers and lengths of the arteries, and the distance between the zygomatic arch and MA, and between the infratemporal crest and MA were measured. The MA was found superficial to the lateral pterygoid in 57.2 percent. The inferior alveolar artery (IA) was arisen from MA before the middle meningeal artery (MM) in 35.7 percent, after MM in 35.7 percent. The IA and MM were arisen from the same area of MA in 14.3 percent. In other two cases IA was arisen from the beginning of MA (14.3 percent). According to the contours of third portion of MA, we classified "Y" type (50 percent), "intermediate-T" type (14.3 percent), and "M" type (35.7 percent). This reinvestigation of the clinical anatomy of MA may provide useful information to the head and neck surgeons, dentists, neurosurgeons and radiologists related with this region.

El objetivo de este estudio fue investigar la anatomía de la arteria maxilar (AM) y sus ramas. Fueron disecados 14 hemicabezas de cadáveres turcos adultos. Las muestras fueron clasificadas de acuerdo a las relaciones entre AM y el músculo pterigoideo lateral. Después de la eliminación del músculo pterigoideo lateral, las partes y las ramas de AM fueron expuestas. Se clasificaron los patrones de ramificación de la AM en la fosa pterigopalatina. El calibre y la longitud de las arterias, la distancia entre el arco cigomático y la AM , y entre la cresta infratemporal y la AM fueron medidas. La AM se encuentra superficial al músculo pterigoideo lateral en el 57,2 por ciento. La arteria alveolar inferior (AI) se originó desde la AM antes que la arteria meníngea media (MM) en el 35,7 por ciento, y después de ésta en el 35,7 por ciento. La AI y MM se originaron en la misma zona de la AM en el 14,3 por ciento. En otros dos casos la AI se originó desde el inicio de AM (14,3 por ciento). De acuerdo con los contornos de la tercera porción de AM, se clasificaron como tipo "Y" (50 por ciento), tipo "intermedio-T" (14,3 por ciento), y de tipo "M" (35,7 por ciento). Esta investigación de la anatomía clínica de la AM puede proporcionar información útil a los cirujanos de cabeza y cuello, odontólogos, neurocirujanos y radiólogos relacionados con esta región.

Anatomical study of the cavernous sinus emphasizing operative approaches.

AIM: The aim of this article is to describe the microsurgical anatomy of the cavernous sinus, the triangles, and the osseous relationships in the region with special attention to the relationships important in surgical approaches on the intracavernous structures. MATERIAL AND METHODS: Fifty cavernous sinuses obtained from twenty-five cadaver heads were studied in detail using magnification. Stepwise dissections of the cavernous sinuses performed to demonstrate the intradural and extradural routes, anatomy of the triangles and osseous relationships in the region. RESULTS: The main branches of the intracavernous portion of the carotid artery were the meningohypophyseal, the inferior cavernous sinus, and McConnell;s capsular artery . The main branches of the meningohypophyseal trunk were the tentorial, the dorsal meningeal, and the inferior hypophyseal artery. There were variations of the main branches of the meningohypophyseal trunk. The sixth cranial may splite into rootlets as it passes lateral to the carotid artery. There were size and shape variation of the triangles. CONCLUSION: Aprecise understanding of the bony relationships, the anatomy of the triangels and neurovascular content of the cavernous sinus, together with the use of cranial base and microsurgical techniques are necessary for safer surgery. Asingle approach is not capable of providing exposure of all parts of the sinus.