ABSTRACT
We examined the relationship between psychological stress and the worsening of glycemic control in diabetic patients at the time of the Great East Japan Earthquake. HbA1c levels in diabetic patients before and after the disaster were evaluated with the General Health Questionnaire (GHQ) and other questions including those on changes in diet, exercise, psychological stress and drug intake in 320 consecutive diabetic patients who had been followed in a diabetes clinic. Logistic regression analysis revealed that the total GHQ scores (odds ratio [OR] 1.03 [95% confidence interval 1.01-1.06]; p<0.01) and interruption of drug intake (OR 4.48 [1.57-12.7]; p=0.01) were independently associated with worsening of glycemic control defined as an increase in the HbA1c level equal to or greater than 0.5%. Among the scores on the GHQ, those for somatic symptoms (OR 1.18 [1.01-1.38]; p=0.03) and sleep disturbances or anxiety (OR 1.26 [1.08-1.46]; p<0.01) were independently associated with glycemic control. These results suggest that psychological stress during a disaster has independent effects on worsening of glycemic control.
Subject(s)
Diabetes Mellitus/psychology , Earthquakes , Hyperglycemia/prevention & control , Hypoglycemia/prevention & control , Stress, Psychological/etiology , Stress, Psychological/physiopathology , Academic Medical Centers , Aged , Anxiety/epidemiology , Anxiety/etiology , Diabetes Mellitus/blood , Diabetes Mellitus/drug therapy , Female , Follow-Up Studies , Glycated Hemoglobin/analysis , Humans , Hyperglycemia/epidemiology , Hypoglycemia/epidemiology , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/supply & distribution , Hypoglycemic Agents/therapeutic use , Japan/epidemiology , Male , Medication Adherence , Middle Aged , Outpatient Clinics, Hospital , Sleep Deprivation/epidemiology , Sleep Deprivation/etiology , Sleep Wake Disorders/epidemiology , Sleep Wake Disorders/etiologyABSTRACT
The 50 premamillary arteries (PremA), arising from 39 posterior communicating arteries (PCoA), were examined in injected human brains. The PremA, which commonly was single (71.8%) and less frequently double (28.2%), more often arose from the PCoA (97.4% ) than from the posterior cerebralartery (PCA) (2.6%). The PremA ranged between 280 and 780 microm in diameter. It gave off side branches to the hypothalamus (23.1%), optic tract (10.2%), mamillary body (17.9%) and the crus cerebri (35.9%). The anastomoses involving the extracerebral segment of the PremA were present in 35.9% of the cases. They varied in caliber from 50 to 230 microm. The intracerebral segment of the PremA ranged from 280 to 490 microm in diameter. Our study gives a precise anatomic basis for safer operations on the aneurysms of the posterior communicating artery and adjacent vessels.
Subject(s)
Circle of Willis/anatomy & histology , Circle of Willis/surgery , Thalamus/blood supply , Corrosion Casting , Humans , Mammillary BodiesABSTRACT
The cavernous region was examined in 20 fetuses, injected with Micropaque, and in 5 adults. The lateral wall of the cavernous region in fetuses was noticed to have four layers. The superficial membrane represents the dural sheath. The second membrane of dense connective tissue involves the trochlear nerve. The third layer, formed by loose connective tissue, involves the oculomotor nerve, and the ophthalmic and maxillary division. The fourth layer, which represents the lateral wall of the cavernous sinus, involves the abducent nerve. The meningohypophyseal trunk can be complete or incomplete. The inferolateral trunk and its branches were found to supply the cavernous portions of the mentioned cranial nerves. The obtained data make the anatomic basis for neurosurgical operations in the cavernous region.
Subject(s)
Cavernous Sinus/anatomy & histology , Adult , Barium Sulfate , Carotid Artery, Internal/anatomy & histology , Carotid Artery, Internal/embryology , Cavernous Sinus/embryology , Cephalometry , Cerebral Veins/anatomy & histology , Cerebral Veins/embryology , Humans , MorphogenesisABSTRACT
Microsurgical anatomy for the pterional approach was studied regarding the origin and the course of the ophthalmic artery and the distal dural ring using human cadaveric specimens, with special reference to the surrounding bony structures. In 50 human adult formalin-fixed cadaveric cerebral hemispheres and 10 block specimens of the skull base region including the ophthalmic artery and the carotid dural ring were examined under magnification using an operating microscope. The ophthalmic artery originated from the intradural portion of the internal carotid artery (ICA), except in 5% where the ophthalmic artery originated extradurally. The extradural origin had two patterns: one was that the ophthalmic artery penetrated the bony optic strut (trans-optic strut pattern) and the other was that it coursed into the optic canal proximally to the optic strut without bone penetration (supra-optic strut pattern). The origin of the intradural ophthalmic artery was commonly located at the medial third of the superior wall of the ICA (78%). The ophthalmic artery was commonly taking an S-shaped course in the intradural portion and entered the optic canal over the optic strut. The distal dural ring was tightly adherent to the internal carotid artery; circumferential sectioning of the dural ring is required to mobilize the internal carotid artery. When approaching juxtadural ring ICA aneurysms via the pterional route, it is important to recognize the extradural origin, especially the trans-optic strut type, and to precisely understand the microsurgical anatomy around the dural ring.
Subject(s)
Carotid Artery Diseases/surgery , Carotid Artery, Internal , Dura Mater/surgery , Intracranial Aneurysm/surgery , Microsurgery , Neurosurgical Procedures , Ophthalmic Artery/anatomy & histology , Ophthalmic Artery/surgery , HumansABSTRACT
The authors examined the lenticulostriate (perforating) arteries in the vascular casts of 48 middle cerebral arteries (MCA), as well as in the MRI or CT scans of 32 patients with cerebral infarcts in the MCA territory. The lenticulostriate arteries ranged between two and 12 in number, and from 80 microm to 1,400 microm in size. They originated from the main trunk, terminal trunks, bifurcation site, and/or leptomeningeal branches of the MCA, either separately or from common trunks (70.8%). The extreme variations of the supplying region of the perforators were noted in seven anatomic specimens. In addition to the basal ganglia, the genu, and the anterior limb of the internal capsule, the lenticulostriate arteries seemed to supply only the rostral portion of the superior part of the posterior limb of the capsule. The patients presented with occlusion of all the lenticulostriate arteries, individual arteries, or only their twigs. Complete occlusion of these arteries resulted in a huge central hemispheric infarct. Occlusion of an individual artery most often caused a large ganglionic-capsular infarct. The authors concluded that the lacunar infarcts usually follow occlusion of a terminal or a side branch of the lenticulostriate arteries.
Subject(s)
Cerebral Arteries/anatomy & histology , Cerebral Arteries/pathology , Cerebral Infarction/pathology , Corpus Striatum/blood supply , Corpus Striatum/pathology , Adolescent , Adult , Aged , Cerebral Angiography , Child , Corrosion Casting , Humans , Magnetic Resonance Angiography , Middle Aged , Tomography, X-Ray ComputedABSTRACT
In this article we demonstrate a computer graphics model to represent the microsurgical anatomy of the supraclinoid portion of the internal carotid artery (ICA). The source of the input data is a variety of publications showing the detailed anatomy of the area. A computer graphics model of the supraclinoid portion of the ICA and relevant structures including perforators and cranial nerves was made under full colour shading using a Z-buffer algorithm. Complicated microstructures including perforators or cranial nerves are depicted in detail, and can be rotated and viewed from any direction, and thus allows understanding of the three-dimensional relations of the area. Using our method, it may be possible to represent more complicated models of various anatomies, and this methodological tool would be useful for teaching surgical microanatomy and pathology and in pre-surgical operative planning and preparation of the surgeon, introducing a new style navigational system for open microneurosurgery.
Subject(s)
Carotid Artery, Internal/anatomy & histology , Cranial Nerves/anatomy & histology , Image Processing, Computer-Assisted , Humans , Image Processing, Computer-Assisted/methods , MicrosurgeryABSTRACT
We previously reported that the mold Monascus anka, traditionally used for fermentation of food, showed antioxidant and hepatoprotective actions against chemically induced liver injuries. In the present study, the antioxidant component of M. anka was isolated and identified. The antioxidant was elucidated to be dimerumic acid. DPPH (1,1-diphenyl-2-picrylhydrazyl) radical was significantly scavenged by the antioxidant whereas hydroxyl radical and superoxide anion were moderately scavenged. When the antioxidant (12 mg/kg) was given to mice prior to carbon tetrachloride (CCl(4), 20 microl/kg, ip) treatment, the CCl(4)-induced liver toxicity in mice seen in an elevation of serum aspartate aminotransferase and alanine aminotransferase activities was depressed, suggesting the hepatoprotective action of the antioxidant. The liver microsomal glutathione S-transferase activity, which is known to be activated by oxidative stress or active metabolites, was increased by CCl(4) treatment and the increase was also depressed by pretreatment with the mold antioxidant. Thus these data confirmed that the dimerumic acid isolated from M. anka is the potential antioxidant and protective against CCl(4)-induced liver injury.
Subject(s)
Antioxidants/chemistry , Free Radical Scavengers/chemistry , Piperazines/chemistry , Yeasts/chemistry , Alanine Transaminase/blood , Animals , Aspartate Aminotransferases/blood , Carbon Tetrachloride/toxicity , Electron Spin Resonance Spectroscopy , Glutathione Transferase/metabolism , Hydroxyl Radical/metabolism , Liver/drug effects , Liver/pathology , Magnetic Resonance Spectroscopy , Male , Mice , Mice, Inbred Strains , Molecular Structure , Oxidative Stress , Piperazines/pharmacology , Superoxides/metabolismABSTRACT
The authors' goal was to develop a computer graphics model to represent the microsurgical anatomy of the basilar artery (BA) bifurcation and surrounding structures to simulate surgery of a BA bifurcation aneurysm performed via the transsylvian approach. The source of the input data was a variety of publications that showed detailed anatomy of the area. A computer graphics model of the area near the BA bifurcation including relevant structures, such as perforating branches or cranial nerves, was depicted in detail. A BA bifurcation aneurysm was added to the computer graphics model and it was rotated to simulate the transsylvian approach. After the internal carotid artery was displaced using a virtual retractor, the aneurysm was exposed, thus providing an understanding of the three-dimensional surgical orientation of the area. Designing a standard anatomical model on the basis of data culled from a variety of publications and adding morphological changes by using a virtual retractor to displace structures that obstruct the view along a critical path at the base of the brain are useful strategies of computer manipulation for surgical simulation in open microneurosurgery. This methodological tool would be useful in teaching surgical microanatomy and in introducing a new navigational system for virtual reality. Both concept and technical details are discussed.
Subject(s)
Basilar Artery/anatomy & histology , Basilar Artery/surgery , Computer Simulation , Microsurgery , Models, Cardiovascular , Computer Graphics , Humans , Magnetic Resonance Imaging , Tomography, X-Ray ComputedABSTRACT
BACKGROUND: The available information about certain microanatomic features of the AChA perforators is incomplete. Precise knowledge of these vessels is necessary to understand the consequences of their occlusion and to safely operate in their region. METHODS: The AChA perforators were microdissected and examined under the stereoscopic microscope in 10 vascular casts and in 20 hemispheres injected with india ink or radiopaque substance. RESULTS: The perforating branches ranged in number from 2 to 9 (mean, 4.6) and in diameter between 90 microm and 600 microm (mean, 317 microm). The most proximal perforator arose 3.2 mm on average caudal to the AChA origin. The most distal (capsulothalamic) perforator varied in size from 200 microm to 610 microm (mean, 431 microm). One or more of the perforators always originated from the AChA (100%), but some of them also from the uncal (33.3%) or parahippocampal branch (10%) of the AChA, either as individual vessels only (70%) or from common trunks (30%). The perforators gave off the peduncular (20%), optic (23.3%), or uncal side branches (26.7%). CONCLUSIONS: Our findings concerning the origin, position, number, size, branching, penetration site, and relationships of the AChA perforators gave the anatomic basis for safe operations in patients with AChA aneurysms or mediobasal limbic epilepsy.
Subject(s)
Cerebral Arteries/anatomy & histology , Choroid Plexus/blood supply , Adult , Aged , Cadaver , Cerebral Arteries/surgery , Choroid Plexus/surgery , Female , Humans , Male , Middle AgedABSTRACT
Antioxidant action of various molds, which are traditionally used for the production of foods or alcoholic beverages in Japan, was studied in vitro and in vivo. Antioxidant action was evaluated by scavenging stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and lipid peroxidation of rat liver microsomes. Among 40 molds, 16 species showed the DPPH scavenging action, and the molds that can scavenge the DPPH radical inhibited lipid peroxidation. The mold with the strongest action, Monascus anka, was chosen for the investigation of a protective action against liver injury of rats. When galactosamine (GalN, 400 mg/kg) or GalN plus lipopolysaccharide (LPS, 0.5 microg/kg) was given intraperitoneally to rats (Sprague-Dawley), aspartate aminotransferase (AST) and glutathione (GSH) S-transferase (GST) activities in serum were significantly increased. However, such hepatotoxicities seen in the increase in serum enzyme levels were depressed when the extract prepared from M. anka was given 1 and 15 h before the toxic insultant. Liver microsomal GST activity, which is known to be activated by oxidative stress, was increased by GalN or GaIN plus LPS treatment and the increase was also inhibited by pretreatment with the extract. Pathomorphological changes in the liver caused by GalN treatment also were prevented by the mold extract. These results indicate that the extract of M. anka has radical scavenging action and ameliorates chemically induced hepatotoxicity.
Subject(s)
Antioxidants/pharmacology , Ascomycota/chemistry , Liver/drug effects , Animals , Aspergillus/chemistry , Cell Extracts/pharmacology , Dithiothreitol/pharmacology , Galactosamine/pharmacology , Glutathione Transferase/metabolism , Liver/pathology , Male , Oxidative Stress , Rats , Rats, Sprague-DawleyABSTRACT
At present, conventional intra-arterial angiography remains the gold-standard for the diagnosis of etiology of subarachnoid hemorrhage (SAH), but this may change as intra-arterial digital subtraction angiography (IA-DSA) or three-dimensional computerized tomography (CT) angiography improve. The purpose of this study is to investigate the reliability of IA-DSA for the diagnosis of SAH of unknown etiology. Of 184 patients admitted to our unit with proven spontaneous SAH between January, 1994, and March, 1997, 124 underwent IA-DSA. Ten were diagnosed as having SAH of unknown etiology by initial angiography; therefore, the incidence of SAH of unknown etiology based on the diagnosis of initial IA-DSA was 8.1%. Of these 10 patients, six patients were treated conservatively in the acute period. Other four patients underwent exploratory surgeries in the acute period due to a great suspicion of the presence of aneurysms. In one patient, no aneurysm was detected; in three patients aneurysms were discovered at surgery and successfully clipped. In two of three patients, aneurysms were not discovered at the suspected site, because radiological findings of a thrombosed aneurysm and infundibular dilatation of a perforator caused incorrect diagnosis of the aneurysm sites. Although the site of aneurysm diagnosed by IA-DSA is not always correct, exploratory aneurysm surgery during the acute period based on the diagnosis by IA-DSA is warranted, and IA-DSA is acceptable for the diagnosis of SAH of unknown etiology.
Subject(s)
Angiography, Digital Subtraction , Subarachnoid Hemorrhage/diagnostic imaging , Subarachnoid Hemorrhage/surgery , Aged , Female , Humans , Intracranial Aneurysm/complications , Male , Middle Aged , Subarachnoid Hemorrhage/etiology , Tomography, X-Ray ComputedABSTRACT
To represent multiple microstructures, including perforators, dura, and cranial nerves, and to allow understanding of the three-dimensional relations of the paraclinoid area, we made a computer graphics model. The source of the input data is a variety of publications showing the detailed anatomy of the paraclinoid area. To produce the model, we traced such data, input selected points for each structure, smoothed the lines with a spline program, and added depth using wire-framing and color alterations. The computer graphic model of the paraclinoid area showing perforators, dural ring, optic nerve, and so forth, was made using a paint method for hidden line removal. It can be rotated and viewed from any direction and thus allows understanding of the relations of the area. Using our method, it may be possible to obtain a more detailed model of various anatomies including the skull base, and such data would be useful for preoperative simulation to understand relative regional relations for a specific case and as a new navigational system for open microneurosurgery. Concepts and technical details of the method are described.
ABSTRACT
A case of a large anomalous anterior choroidal artery (AchA) associated with internal carotid artery-posterior communicating artery aneurysm is reported. At surgery, the large anomalous AchA mimicked the PcomA. Therefore, we initially mistook the large anomalous AchA for the PcomA, and the ICA-PcomA aneurysm for the dorsal ICA aneurysm arising at a location of other than an arterial division. This is a rare case of an anomaly of the AchA with an associated aneurysm found at surgery. Anatomical and surgical considerations are made.
Subject(s)
Aneurysm/diagnosis , Carotid Artery Diseases/diagnosis , Cerebral Arteries/abnormalities , Choroid Plexus/blood supply , Intracranial Aneurysm/diagnosis , Aneurysm/complications , Carotid Artery Diseases/complications , Carotid Artery, Internal , Humans , Intracranial Aneurysm/complications , Male , Middle AgedABSTRACT
To contribute to a better understanding of the clipping operation of the basilar bifurcation aneurysm, factors influencing the surgical outcome were analyzed in 80 patients. The age range of the patients was 34-74 years, with a mean age of 58.4 years, and there were 61 females and 19 males. Fifty-eight patients had been admitted because of subarachnoid hemorrhage and a basilar bifurcation aneurysm ruptured in 49 patients. The size of the aneurysms ranged between 2 and 19 mm with a mean of 7.9 +/- 3.9 mm. The height of the aneurysm neck was between -10 and 17 mm measured above a biclinoid line with a mean of 4.8 +/- 5.2 mm. Pterional approach was utilized in 72 patients and subtemporal in eight. Optic unroofing or removal of anterior clinoid process were performed in five patients, zygomatic osteotomy in 10, posterior clinoid removal in seven, and anterior petrosectomy in one. A bridging vein of the temporal lobe was divided in 16 patients. A short and/or hypoplastic posterior communicating artery was divided in 11 patients. Temporary occlusion of the basilar trunk was performed in 39 patients. Surgical outcome (Glasgow Outcome Scale) at 3 months after the operation was good recovery in 42 (53%), moderately disabled in 23 (29%), severely disabled in five (6%), vegetative survival in two (3%), and dead in eight (10%). The aneurysm size proved to be a single preoperative factor which significantly correlated with the surgical outcome (Spearman's rank correlation test, p < 0.0001). Division of the posterior communicating artery significantly contributed to the surgical outcome as an intraoperative factor (Mann-Whitney's U test, p = 0.01). The larger the aneurysm size was, the more often the posterior communicating artery was sectioned. Extreme care should be taken to obliterate a large aneurysm with a clip graft especially when division of the posterior communicating artery is required.
Subject(s)
Basilar Artery/surgery , Intracranial Aneurysm/surgery , Adult , Aged , Female , Humans , Male , Middle Aged , Retrospective Studies , Surgical Instruments , Treatment OutcomeABSTRACT
BACKGROUND: While the characteristics of the vasculature of the second (intracanalicular) segment of the hypoglossal nerve are well known, the vascularization of the first (cisternal) segment of this nerve has not been examined so far. Many pathologic processes and malformations can be located in the premedullary cistern, which may affect the vasculature of the cisternal segment. Consequently, we decided to examine the blood supply of the cisternal segment. METHODS: The anatomic features of the cisternal segment and its vasculature were examined in 15 hypoglossal nerves after injection of india ink and gelatin into the vertebrobasilar arterial system. RESULTS: The cisternal segment was noted to consist of 3-15 long roots, which usually formed two trunks of the hypoglossal nerve. The roots of each nerve received blood from the anterolateral and the lateral medullary arteries, which ranged from 3 to 5 in number and between 100 microns and 500 microns in caliber. These arteries may arise from the perforating branches or the pontomedullary branch of the basilar artery; the vertebral artery or its perforators; the anterior spinal artery or its vascular roots; the posterior spinal artery; and the posterior inferior cerebellar artery. The main hypoglossal arteries, which ranged in diameter from 20 microns to 80 microns, always coursed along the dorsal surface of the roots of the hypoglossal nerve. CONCLUSIONS: The cisternal segment of the hypoglossal nerve was always vascularized by several vessels, which mainly originated from the vertebral artery and its branches. This observation was discussed from the neurosurgical point of view.
Subject(s)
Hypoglossal Nerve/blood supply , Microsurgery , Cadaver , Cisterna Magna , Humans , Hypoglossal Nerve/surgeryABSTRACT
In this report we demonstrate the application of computer assisted geometric design in the surgery of a carotid cave aneurysm. The method and basic concepts have been previously reported.(1) In this case report we referred to the previously published atlas of clinical images to input anatomical data. This enabled us to demonstrate and adequately identify microneurostructures for surgical simulation. The concepts and basic methods of computer assisted geometric design of microneurostructures are described.
ABSTRACT
OBJECTIVE: Despite detailed studies of the perforating arteries, their relationships with the leptomeningeal arteries are almost unknown. These relationships can be of great significance during neurosurgical operations. METHODS: The arteries of the hemispheres, which ranged in number from 17 to 36, were injected with india ink or methylmethacrylate. RESULTS: The perforating vessels were noted to arise from the following leptomeningeal arteries: the subcallosal branch of the anterior communicating artery (26.6%); the median artery of the corpus callosum (6.6%); the medial orbitofrontal (6.6%) and the olfactory branch (3.3%) of the anterior cerebral artery; the accessory middle cerebral artery (3.3%); the frontal and temporal branches of the middle cerebral artery (66.6%); the temporal branches of the internal carotid and the anterior choroidal arteries (25% each); the peduncular branch of the posterior communicating artery (4.8%); the peduncular, collicular and medial posterior choroidal branches of the posterior cerebral artery (40%); the cerebellar branches (100%); the long pontine branches (20-26.6%); the anterolateral branches (33.3%) of the basilar artery; and the anterolateral or the lateral medullary branches (35.3%) of the vertebral artery. From 19.4 to 100% of some leptomeningeal vessels originated in the large perforating arteries. CONCLUSION: From 4.8 to 100% of certain groups of the perforating vessels originated in the leptomeningeal arteries. Occlusion of a leptomeningeal artery that gives rise to the perforating vessel(s) may lead to superficial and deep infarcts in the same patient.
Subject(s)
Brain/blood supply , Carbon , Meninges/blood supply , Arteries/anatomy & histology , Arteries/surgery , Coloring Agents , Dominance, Cerebral/physiology , Histological Techniques , Humans , Methylmethacrylate , Methylmethacrylates , Microsurgery , Reference ValuesABSTRACT
The trigeminocerebellar artery was found on the left side in one of 22 brainstems, with the vasculature injected with India ink or methylmethacrylate. The trigeminocerebellar artery, which measured 910 microns in diameter, arose from the basilar artery. The artery was divided into the pontine, trigeminal, cerebellopontine, and cerebellar segments. The artery supplied the anterolateral and lateral part of the pons, the trigeminal nerve root, the middle cerebellar peduncle, and most of the petrosal surface of the cerebellar hemisphere. Although relatively rare, the trigeminocerebellar artery may cause trigeminal neuralgia. Occlusion of this artery would cause a syndrome similar to the lateral midpontine syndrome. The trigeminocerebellar artery could be misinterpreted on angiograms as the anterior inferior cerebellar artery with a high origin from the basilar artery.
Subject(s)
Brain Stem/anatomy & histology , Cerebral Arteries/anatomy & histology , Trigeminal Nerve/anatomy & histology , Adult , Aged , Cerebellum/anatomy & histology , Humans , Middle AgedABSTRACT
We report a subgroup of internal carotid artery (ICA) aneurysms located near the carotid ring which we call juxtadural ring aneurysms. These aneurysms are classified into three types: paraclinoid intradural, carotid cave and infraclinoid extradural aneurysms. The paraclinoid intradural aneurysms arise from the ICA distal to the origin of the ophthalmic artery and are close to the dural ring, which may include some so-called carotid-ophthalmic aneurysms. The carotid cave aneurysms are located in the carotid cave which is seated in the infraclinoid carotid groove and proximal to the origin of the ophthalmic artery. They are located at the angiographical genu and in the intradural space anatomically. The infraclinoid extradural aneurysms are located close to the dural ring extradurally in the infraclinoid carotid groove sinus, a peripheral venous space of the cavernous sinus. The infraclinoid extradural aneurysms should be differentiated from aneurysms in the cavernous sinus, because they are located in the infraclinoid carotid groove sinus.
ABSTRACT
We examined in detail the cisternal segments of 15 trochlear nerves in brain stems injected with India ink and fixed in formalin. The nerves were found to emerge as singular trunks (33.3%), singular trunks with accessory rootlets (13.3%), or two or three roots with (26.7%) or without accessory rootlets (26.7%). The nerves were in close relationship or in contact with the superior cerebellar artery, that is, with the main trunk of the superior cerebellar artery, its medial and lateral terminal stems, the accessory superior cerebellar artery, and the vermian, paravermian, collicular, and lateral hemispheric arteries as well as their small branches. Some of these vessels were connected by anastomoses in 86.7% of the cases. The anastomotic channels varied from 40 to 530 microns in diameter. The cisternal segment of each trochlear nerve was usually supplied by a single long artery, which most often arose from the vermian artery (26.7%) or the collicular artery (26.7%). The feeding vessel ranged from 30 to 80 microns in caliber. We discuss the possible clinical significance of the anatomic data observed in the present study.