Clinical Relevance of the Variability of the Infraorbital Arterial Anatomy Evaluated by Three-Dimensional Computed Tomography.

BACKGROUND: Knowledge of the anatomy of the infraorbital artery (IOA) is crucial for the rejuvenation of the anterior medial aspect of the midface; however, studies adequately describing the anatomy of the IOA branches are lacking, and their connection with the ophthalmic artery branches remains unclear. OBJECTIVES: This study aims to elucidate the anatomical characteristics of the IOA in its deployment within the lower eyelid using three-dimensional (3D) technology, thereby offering an anatomical foundation for clinical surgical procedures. METHODS: An analysis was conducted on computed tomography scans of 132 cadaveric head sides post-contrast injection, utilizing the Mimics software for reconstruction. The study focused on examining the anastomosis of the IOA, its principal branches, and the branches emanating from the ophthalmic artery. RESULTS: The prevalence of type I IOA was observed at 38.6% (51/132), while Type II IOA was found in 61.4% (81/132) of cases. A 7.6% incidence (10/132) of IOA directly anastomosing with the angular artery was noted. The presence of palpebral branches (PIOA) was identified in 57.6% (76/132) of instances. In the lower eyelid, four distinct distribution patterns of IOA were discerned: The likelihood of Type I PIOA was 5.3%, whereas for Types IIA, IIB, and IIC PIOA, the probabilities were 8.3%, 32.6%, and 11.4%, respectively. The occurrence of the orbital branch of IOA was recorded at 41.7% (55/132). CONCLUSIONS: 3D technology can map IOA variants and identify the deployment patterns of IOA branches in the lower eyelid vascular vesicles at high resolution as a guide in clinical practice. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Endoscopic endonasal surgical anatomy of the optic canal: key anatomical relationships between the optic nerve and ophthalmic artery.

PURPOSE: A detailed understanding of the neurovascular relationships between the optic nerve (ON) and the ophthalmic artery (OA) in the optic canal (OC) is paramount for safe surgery. We focused on the neurovascular anatomy of this area from both an endoscopic endonasal and transcranial trajectories to compare the surgical exposures and perspectives offered by these different views and provide recommendations to increase the intraoperative safety. METHODS: Twenty sides of ten formalin-fixed, latex-injected head specimens were utilized. The surgical anatomy and anatomical relationships of the OA in relationship to the ON along their intracranial and intracanalicular segments was studied from endoscopic endonasal and transcranial perspectives. RESULTS: Three types of OA-ON relationships at the origin of the OA were identified: inferomedial (type 1, 35%), inferior (type 2, 55%), and inferolateral (type 3, 10%). The endoscopic endonasal trajectory offers an inferomedial perspective of the ON-OA neurovascular complex, in which the OA, especially when located inferomedially, is first encountered. When comparing with the transcranial view, all OA were covered by the nerve, type 1 was located below the medial third, type 2 below the middle third, and type 3 below the lateral third of the OC. The mean extension of the intracanalicular portion of both OA and ON was 8.9 mm, while the intracranial portion of the OA and ON were 9.3 mm and 12.4 mm, respectively. The OA, endoscopically, is located within the inferior half of the OC, and occupies 39%, 43%, and 42% of the OC height at its origin, mid, and end points, respectively. The mean distance between the superior margin of the OC at its origin and superior margin of the OA is 1.4 mm. CONCLUSIONS: Detailed anatomical understanding of the OC, and the ON and OA at their intracranial and intracanalicular segments is paramount to safe surgery. When opening the OC dura endoscopically, our results suggest that a medial incision along the superior third of the OC with a proximal to distal direction is recommended to avoid injury of the OA.

Evaluation of Supratrochlear, Supraorbital and Angular Artery Course Variations and Depth by Doppler Ultrasound.

BACKGROUND: Supratrochlear (STA), supraorbital (SOA), and dorsal nasal artery (DNA) branches from the ophthalmic artery and angular artery (AA) from the facial artery are the primary suppliers of blood to the upper face. Filler injection without precise knowledge of its vascular topography poses a risk of severe complications. METHODS: Seventy-four hemifaces from 37 subjects with a median age of 25.0 (21.0, 35.0) years and a median body mass index of 21.2 (20.0, 25.4) kg/m2 underwent high-frequency ultrasound tests between March 2022 and April 2022. The bilateral location, depth, peak systolic velocity (PSV), and inner diameter (ID) of the four periorbital arteries (STA, SOA, DNA, AA) were measured. RESULTS: The average ID ranges from 0.6~1.0 mm, and the average PSV ranges from 9.2~24.9 cm/s. All arteries detected passed through the superficial subcutaneous fascia. Most subjects' STAs traveled within 1.0 to 2.0 cm from the midline (left 96.8%, right 93.8%), while SOAs were mainly concentrated within 2.0 to 4.0 cm (left 83.9%, right 81.3%). STAs were more superficial and had a larger internal ID and PSV than SOAs (p<0.001). Except for the ID of the right SOA2 being significantly larger than that of the left SOA2 (p<0.05), no dominant side was found. The depth of STAs and SOAs was moderately correlated with BMI (p<0.05), except for STA1 on the left side. The course of AAs presented a high variability. CONCLUSION: These findings emphasize that the periorbital arteries carry with it a likelihood of ocular complication risks during injection. Targeting the supraperiosteal layer in the STA area and the supramuscular layer in the SOA area of the inferior forehead during injection seems reasonable, and an area within 1.0~2.0 cm from the midline should be avoided. Additionally, the high variability of AAs will enhance the understanding of the anatomy of the facial artery terminals. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A case series: 3-dimensional computed tomographic study of the superior orbital vessels: Superior orbital arcades and their relationships with the supratrochlear artery and supraorbital artery.

BACKGROUND: Vascular complications from periorbital intravascular filler injection are major safety concerns. OBJECTIVE: To thoroughly describe the superior orbital vessels near the orbital rim and propose considerations for upper eyelid and forehead injections. METHODS: Fifty-one cadaver heads were infused with lead oxide contrast media through the external carotid artery, internal carotid artery, and facial and superficial temporal arteries. Computed tomography (CT) images were obtained after contrast agent injection, and 3-dimensional CT scans were reconstructed by using a validated algorithm. RESULTS: Eighty-six qualified hemifaces clearly showed the origin, depth, and anastomoses of the superior orbital vessels, which consistently deployed 2 distinctive layers: deep and superficial. Of all hemifaces, 59.3% had deep superior orbital vessels near the orbital rim, including 44.2% with deep superior orbital arcades and 15.1% with deep superior orbital arteries, which originated from the ophthalmic artery. Additionally, 97.7% of the hemifaces had superficial superior orbital arcades, for which 4 origins were identified: ophthalmic artery, superior medial palpebral artery, angular artery, and anastomosis between the angular and ophthalmic arteries. LIMITATIONS: The arterial depth estimated from 3-dimensional CT needs to be confirmed by standard cadaver dissection. CONCLUSION: This study elucidated novel arterial systems and proposed considerations for upper eyelid and forehead injections.

Site of Origin of the Ophthalmic Artery Influences the Risk for Retinal Versus Cerebral Embolic Events.

BACKGROUND: Embolic events leading to retinal ischemia or cerebral ischemia share common risk factors; however, it has been well documented that the rate of concurrent cerebral infarction is higher in patients with a history of transient ischemic attack (TIA) than in those with monocular vision loss (MVL) due to retinal ischemia. Despite the fact that emboli to the ophthalmic artery (OA) and middle cerebral artery share the internal carotid artery (ICA) as a common origin or transit for emboli, the asymmetry in their final destination has not been fully explained. We hypothesize that the anatomic location of the OA takeoff from the ICA may contribute to the differential flow of small emboli to the retinal circulation vs the cerebral circulation. METHODS: We report a retrospective, comparative, case-control study on 28 patients with retinal ischemia and 26 patients with TIA or cerebral infarction caused by embolic events. All subjects underwent either computed tomography angiography or MRA. The location of the ipsilateral OA origin off the ICA was then graded in a blinded fashion and compared between cohorts. Vascular risk factors were collected for all patients, including age, sex, hypertension, hyperlipidemia, arrhythmia, diabetes, coronary artery disease, and smoking. RESULTS: We find that in patients with retinal ischemia of embolic etiology, the ipsilateral OA takeoff from the ICA is more proximal than in patients with cerebral infarcts or TIA (P = 0.0002). We found no statistically significant differences in demographic, vascular, or systemic risk factors. CONCLUSIONS: We find that the mean anatomical location of the OA takeoff from the ICA is significantly more proximal in patients with MVL due to retinal ischemia compared with patients with TIA or cerebral ischemia. This finding contributes significantly to our understanding of a long observed but poorly understood phenomenon that patients with MVL are less likely to have concurrent cerebral ischemia than are patients with TIA.

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.

Anatomic features of the cranial aperture of the optic canal in children: a radiologic study.

OBJECTIVE: This study aimed to peruse anatomic features of the cranial aperture of the optic canal (CAOC) for obtaining an extended morphometric dataset in children. METHODS: Computed tomography images of 200 children were included in this retrospective work to analyze the shape, location and diameters of the CAOC. RESULTS: The CAOC area, width and height were observed as 17.53 ± 2.80 mm2, 6.12 ± 0.84 mm, and 4.35 ± 0.64 mm, respectively. The angle of the optic canal in axial plane was found as 39.28 ± 5.13°, while in sagittal plane as 16.01 ± 6.76°. The distance between the CAOC and the midsagittal line was 7.17 ± 1.48 mm. The CAOC was measured as 54.04 ± 5.23 mm and 42.55 ± 3.28 mm away from the anterior and lateral boundary of the anterior skull base, respectively. The CAOC shape was described as the tear-drop (186 foramina, 46.5%), triangular (156 foramina, 39%), oval (47 foramina, 11.8%), and round (11 foramina, 2.8%). CONCLUSION: The depth, angle and diameter measurements belonging to the CAOC were changing according to its shape or demographic data (e.g., sex and age). Therefore, preoperative radiologic evaluation containing the shape, location and size of the CAOC should be considered by multidisciplinary operating teams in terms of surgical interventions such as implant positioning.

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.

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.

Analysis of anatomical variation of the inclination of lamellas attached to the skull base and its correlation with the anterior ethmoidal artery floating in the ethmoid sinus for use in endoscopic sinus surgery.

PURPOSE: Attention to the inclination of lamellas attached to the skull base, including the basal lamella of the middle turbinate, facilitates the intraoperative identification of each lamella without requiring the use of a navigation system. We classified the inclination between the lamella and the skull base in preoperative computed tomography (CT) images and examined the relationship between the lamellas attached to the skull base, including the basal lamella of the middle turbinate, and the position of the anterior ethmoidal artery (AEA). We aimed to develop a preoperative classification to help prevent intraoperative injury of the AEA. METHODS: We retrospectively investigated the paranasal sinus sagittal section CT slices of 366 sides of 183 patients to assess the inclination of lamellas attached to the skull base and the AEA location. We also reviewed the AEA position, its correlation with the supraorbital ethmoid cell, and the lateral lamella of the cribriform plate. RESULTS: We classified the lamella inclination at the skull base as the anterior direction, perpendicular direction, and posterior direction types. Lamellas containing a floating AEA inclined in the anterior direction toward the skull base were observed in 68.9% of sides, inclination in the perpendicular direction was noted in 30.5% of sides, and inclination in the posterior direction was noted in 0.5% of sides. CONCLUSION: It is easier to identify the AEA intraoperatively when the lamella inclination of the skull base attachment is recognized based on preoperative CT findings. This approach could be applied to all paranasal sinus lamellas and assist in identifying the AEA and other nearby structures.

The approach angle to the interoptic triangle limits surgical workspace when targeting the contralateral internal carotid artery.

BACKGROUND: The interoptic triangle (IOT) offers a key access to the contralateral carotid artery's ophthalmic segment (oICA) and its perforating branches (PB), the ophthalmic artery (OA), and the superior hypophyseal artery (SHA). It has been previously reported that the assessment of IOT's size is relevant when attempting approaches to the contralateral oICA. However, previous studies have overseen that, since the oICA is a paramedian structure and a lateralized contralateral approach trajectory is then required, the real access to the oICA is further limited by the approach angle adopted by the surgeon with respect to the IOT's plane. For this reason, we determined the surgical accessibility to the contralateral oICA and its branches though the IOT by characterizing the morphometry of this triangle relative to the optimal contralateral approach angle. METHODS: We defined the "relative interoptic triangle" (rIOT) as the two-dimensional projection of the IOT to the surgeon's view, when the microscope has been positioned with a certain angle with respect to the midline to allow the maximal contralateral oICA visualization. We correlated the surface of the rIOT to the visualization of oICA, OA, SHA, and PBs on 8 cadavers and 10 clinical datasets, using for the last a 3D-virtual reality system. RESULTS: A larger rIOT correlated positively with the exposure of the contralateral oICA (R = 0.967, p < 0.001), OA (R = 0.92, p < 0.001), SHA (R = 0.917, p < 0.001), and the number of perforant vessels of the oICA visible (R = 0.862, p < 0.001). The exposed length of oICA, OA, SHA, and number PB observed increased as rIOT's surface enlarged. The correlation patterns observed by virtual 3D-planning matched the anatomical findings closely. CONCLUSIONS: The exposure of contralateral oICA, OA, SHA, and PB directly correlates to rIOT's surface. Therefore, preoperative assessment of rIOT's surface is helpful when considering contralateral approaches to the oICA. A virtual 3D planning tool greatly facilitates this assessment.

Three-Dimensional Computed Tomographic Study on the Periorbital Branches of the Ophthalmic Artery: Arterial Variations and Clinical Relevance.

BACKGROUND: Filler injection is a popular cosmetic procedure, but it can entail vascular complications. Periorbital injections have the highest risk within the entire injection area. OBJECTIVES: The authors sought to systematically screen for periorbital arterial variations prior to treatment. METHODS: The external carotid arteries of 10 cadaveric heads were infused with adequate lead oxide contrast. The facial and superficial temporal arteries of another 11 cadaveric heads were injected with the contrast in sequential order. Computed tomography (CT) scanning was performed after injection of contrast, and 3-dimensional (3D) CT scans were reconstructed using validated algorithms. RESULTS: Three types of periorbital blood vessels were found to derive from the ophthalmic artery, including 30% directly originating from the ophthalmic artery, 65% originating from its trochlear branch, and 5% originating from its supraorbital branch. In the forehead, the ophthalmic artery, originating from the internal carotid arteries, formed anastomoses between the frontal branch of the superficial temporal artery, originating from the external carotid artery, with the deep and superficial branches of the supratrochlear and supraorbital arteries, respectively. The lateral orbit and malar plexus can be classified into 4 types based on the trunk artery: the zygomatic orbital artery (27%), the transverse facial artery (23%), the premasseteric branch of the facial artery (19%), and all 3 contributing equally (31%). CONCLUSIONS: Postmortem 3D CT can map periorbital arterial variations. The branching pattern of the ophthalmic artery, the ophthalmic angiosome in the forehead, and the distribution of the lateral orbit and malar plexus were identified at high resolution to guide clinical practice.

Arterial Blood Supply of the Nose: An Angiographic Study.

OBJECTIVE: To define anatomical variations associated with arterial blood supply of the nose which has clinical implications on the management of different disorders, especially intractable posterior epistaxis. STUDY DESIGN: Case series. METHODS: Selective angiography of external and internal carotid arteries of 100 patients scheduled for routine angiography was done. RESULTS: Different anatomical variations were documented. The ophthalmic artery can arise from the middle meningeal artery in 1% while ethmoidal arteries can be absent in 5%. The maxillary artery courses as 2 loops in the pterygopalatine fossa in 64% of cases where the descending palatine artery originates before the first loop or on its top so that caution is needed in controlling epistaxis. The sphenopalatine artery has different patterns of branching and may have more than 2 branches in 18% of cases. In 19% of cases, there is cross-circulation between both sides through the nasal blood supply. CONCLUSION: Angiographic study of the nose is a very helpful tool for accurate knowledge of anatomical variations of the arteries with a tremendous effect on our surgical approaches and techniques for the management of different diseases in the nasal region, especially intractable posterior epistaxis.

The facial artery: A Comprehensive Anatomical Review.

The facial artery is the major vessel supplying blood to the face so its location and course are very important for the safe manipulation of both surgical and non-surgical interventions. This study documents current anatomical information about the facial artery and its tributaries. The terminology of the facial artery tributaries was revisited with reference to the Terminologica Anatomica and novel nomenclature was suggested with anatomical features. The tributaries to the lower lip (inferior labial artery), labiomental region (horizontal and vertical labiomental artery), upper lip (superior labial artery), nose (inferior and lateral alar artery and nasal septal artery), angular and ocular region (angular artery and detoured branch) and the course, layers and location of the facial artery main trunk were revisited with contemporary anatomical studies. The facial artery and its tributaries have close topographical connections to the facial expression muscles, nasolabial groove, and vermilion border, and these also distinguish facial landmarks comprising the cheilion, stomion, and gonion. Interestingly, in contrast to previous descriptions, some terminal branches did not take a straight course but a detoured course. The angular artery was connected to the ophthalmic artery branches and in some cases did not originate from the facial artery. Vascular complications of the facial artery tributaries are frequently seen in the angular, dorsum of the nose, tip of the nose, and glabellar region. This detailed review focusing on facial arterial topography in the various areas of the face would help to enhance quality of treatment. Clin. Anat. 31:99-108, 2018. © 2017 Wiley Periodicals, Inc.

The Gracillimus Orbitis Muscle.

The gracillimus orbitis muscle is an anomalous, accessory, or supernumerary extraocular muscle that, although is rarely seen clinically in the human orbit, has been identified in 5% to 14% of dissected cadaver orbits. It arises from the medial surface of the levator near its origin and runs forward between the levator and superior oblique muscles resembling one of the other extraocular muscles. More anteriorly, it becomes thinner, less well defined, and mostly fibrous. Its major insertion is into the fascia surrounding the trochlea, while other fibers may travel to the supratrochlear artery, intermuscular septum, the levator or medial rectus muscle, and the fascia surrounding the superior ophthalmic vein. The function of this anomalous muscle remains unknown in most cases. Knowledge of its presence is important as the oculoplastic/orbital surgeon may encounter it during an eyelid or orbital procedure.

Anatomic Study of Ophthalmic Artery Embolism Following Cosmetic Injection.

INTRODUCTION: Cosmetic injections of dermal fillers or fat could cause ophthalmic artery embolism and even blindness, the high-risk regions of which are considered glabellar, nasal dorsum, and nasolabial fold. Understanding anatomy of the related arteries is important for a physician to safely perform filler injections. To investigate the mechanisms of ophthalmic artery embolism following the injections, cadaver anatomy was studied. METHODS: Ophthalmic artery, facial artery, their branches, and anastomoses among them were anatomized in 12 fresh cadavers. Mimetic injections of hyaluronic acid were performed in glabellar region, nasal dorsum, and nasolabial fold, the relationships between injected filler and related arteries were then investigated. RESULTS: It was clearly found that 4 arteries were located in common injection regions and connected to ophthalmic artery: supratrochlear artery, supraorbital artery, dorsal nasal artery, and angular artery. In the glabellar region, the deep injection on the periosteum will be risky to injure supratrochlear artery and supraorbital artery, whereas in nasal dorsum and nasolabial fold, the sub- superficial musculo aponeurotic system layer injection has the possibility to injure dorsal nasal artery, angular artery, and facial artery. CONCLUSION: The anatomic mechanism of ophthalmic artery embolism is the anastomoses among the related arteries and ophthalmic artery. Based on the findings of the study, injections in periosteum layer at glabellar region or sub-superficial musculo aponeurotic system layer of nasal dorsum and nasolabial fold are not advised.

Frontal Sinus Pneumatization Affects Height of the Lateral Lamella and Position of Anterior Ethmoidal Artery.

Preoperative evaluation of the frontal sinus (FS) and associated anatomical structures may reduce the risk of intraoperative complications and facilitate the management of potential complications. In this study, the authors aimed to evaluate relationship between FS pneumatization and critical anatomical structures. Paranasal sinus computerized tomography scans of 350 sides of 175 patients were evaluated. The pneumatization pattern of the FS, FS dimensions (on the axial, coronal, and sagittal slices), anterior ethmoidal artery, and depth of the of olfactory fossa were evaluated for every patient on both sides. There were 111 (63.4%) male and 64 (36.6%) female patients. The authors found a statistically significant correlation between the depth of olfactory fossa and the anterior ethmoidal artery position (P <0.001). As the FS pneumatization increases, the likelihood of the anterior ethmoid artery to run separately from the skull base also increases. Also, there was a statistically significant difference among the types in terms of the depth of the olfactory fossa (Kruskal-Wallis P = 0.002). The depth of the olfactory fossa increases depending on the increase of FS pneumatization.Our study shows that the olfactory fossa depth (skull-base depth) increases as FS pneumatization increases. In light of this information, the evaluation of the preoperative sinus computerized tomography scans will help in performing safer endoscopic sinus surgeries.

Periorbital and Intraorbital Studies of the Terminal Branches of the Ophthalmic Artery for Periorbital and Glabellar Filler Placements.

BACKGROUND: Filler injections for sunken upper eyelid correction and glabellar augmentation at the orbitoglabellar region need to be performed correctly. Precise knowledge of the emerging sites of all terminal branches of the ophthalmic artery is essential for these procedures to be conducted safely. METHODS: The terminal branches of the ophthalmic artery were studied in both periorbital and intraorbital dissections. The aim of this study was to verify the critical positions of the emerging sites at the orbital septum that may act as potential retrograde channels for filler emboli. RESULTS: In the 40 eyes examined, the branches of the ophthalmic artery were found to emerge from four different sites. Two substantial emerging sites were situated on both sides of the trochlea of the superior oblique muscle. These sites were located at the superior part of the medial orbital rim (SMOR) and are alternatively named as the epitrochlear and the subtrochlear emerging sites. The other two sites can be regarded as accessory emerging sites due to the comparably smaller artery. Dissection of the intraorbital region revealed small periosteal branches of the infraorbital artery which coursed anteriorly on the orbital floor to form anastomoses with the lacrimal artery. In other areas of the orbital floor, no branches extended from the infraorbital artery. In front of the lacrimal gland, very minute branches descended and coursed along both margins of the superior tarsus but did not course outside the lateral orbital rim. CONCLUSION: A danger zone was located at the SMOR, where the ophthalmic branches emerge to form anastomotic channels. Compression at the trochlea guarantees safe injection of filler, reducing the risk of complication. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

An update on the variations of the orbital blood supply and hemodynamic.

PURPOSE: Several variations of the arterial blood supply of the orbit have been reported over the years. This review is aimed to provide an update focusing on three important issues: (a) variations of the ophthalmic artery origin; (b) contribution of the external carotid artery to the orbital blood supply; (c) orbital hemodynamic. METHODS: A PubMed and Google search was carried out with the following keywords: ophthalmic artery origin, ophthalmic artery anastomoses and ophthalmic artery anatomy. RESULTS: The site of origin of the ophthalmic artery displays a limited number of variations. However they are important as they are also associated with course variations. Anastomoses between the ophthalmic artery and the external carotid artery are numerous and many of them can acquire clinical relevance. Records on their anatomic frequency are limited. Orbital hemodynamic variations are a poorly studied subject. Recent investigations in children have unveiled unexpected variability and instability in the way the blood flows through the orbit. CONCLUSIONS: The orbit shows several possible arterial variations. Some of them have a profound influence on its hemodynamic at least in children. More studies are required to ascertain if the hemodynamic variability observed in children can be pinpointed also in adults.

Bilateral carotid-anterior cerebral artery anastomoses associated with bilateral ophthalmic arteries arising from the middle meningeal arteries diagnosed by magnetic resonance angiography: a case report.

Anastomosis between the ophthalmic segment of the internal carotid artery and the A1-A2 junction of the anterior cerebral artery (ACA), described as carotid-ACA anastomosis or infraoptic course of the ACA, is rare and known to demonstrate right-sided predominance. We report a case of bilateral carotid-ACA anastomoses associated with bilateral ophthalmic arteries arising from the sphenoidal branch of the middle meningeal artery that were diagnosed by magnetic resonance (MR) angiography. Identification of rare arterial variations on MR angiography requires careful scrutiny of source images.