Arterial supply of the upper cranial nerves: a comprehensive review.

The arterial supply to the upper cranial nerves is derived from a complex network of branches derived from the anterior and posterior cerebral circulations. We performed a comprehensive literature review of the arterial supply of the upper cranial nerves with an emphasis on clinical considerations. Arteries coursing in close proximity to the cranial nerves regularly give rise to small vessels that supply the nerve. Knowledge of the arteries supplying the cranial nerves is of particular importance during surgical approaches to the skull base.

The neurovascular relationships of the oculomotor nerve.

In this study, the arterial supply of the cisternal (initial) and the subcavernous parts of the oculomotor nerve (ON) and the relation between the nerve and adjacent vascular structures like posterior cerebral artery (PCA) and superior cerebellar artery (SCA) were investigated. A total of 140 formalin fixed hemispheres from 70 human cadaveric brains were examined. The nutrient branches reaching the cisternal and subcavernous parts of the ON were investigated, along with branches of adjacent vascular structures penetrating the nerve and passing through it. In the material examined, the ON, after arising from the midbrain, mostly continues laterally between PCA and SCA or between PCA and the rostral SCA trunk. However, in three hemispheres of our specimens, the ON run between the rostral and caudal SCA trunks. We observed that the branches of PCA-P1 segment supplied the cisternal part of the ON in all specimens. In one specimen, the cisternal part of the ON was supplied by a branch arising from the rostral SCA trunk which was also originating from PCA. Differently, in four hemispheres, branches arising from PCA or SCA perforated the cisternal part of the ON and passed through it. We also observed a tortuous caudal trunk of duplicated SCA in one of our specimens and considered it as a rare variation. The anatomy of the ON and its vascular relations is significant in terms of not only understanding the compression syndromes and its vascular dysfunctions, but the exact diagnosis and treatment as well.

Development of cranial nerve palsy shortly after endosaccular embolization for asymptomatic cerebral aneurysm: report of two cases and literature review.

CLINICAL DESCRIPTION: We report two cases of asymptomatic cerebral aneurysm in which cranial nerve palsy (CNP) developed shortly after symbolization. The CNP occurred immediately in case 1, but case 2 showed the CNP 30 h after symbolization. Although both aneurysms had increased in size on follow-up angiography, case 2 who showed dome re canalization resulted in progressive CNP deterioration. CONCLUSION: These findings suggest that the CNP may result not only from mechanical compression by coils but also from inflammation induced by perpendicular thrombosis, and that the prognosis of the CNP may be influenced by dome re canalization. This complication should be kept in mind in treatment for asymptomatic aneurysms adjacent to the cranial nerves.

Internal carotid artery occlusion manifesting only as oculomotor nerve palsy.

Oculomotor nerve palsy is very rare as the only manifestation of internal carotid artery (ICA) occlusion, and the angiographic findings have not been described in detail. We present a case of ipsilateral ICA occlusion manifesting as only sudden onset of oculomotor nerve palsy. Cerebral angiography showed occlusion of the ICA from the cervical portion to the ophthalmic portion. Distal blood flow was compensated through an anastomosis from other arteries. Ischemia of the oculomotor nerve was thought to be caused by loss of supply from branches arising from the occluded cavernous portion of the ICA.

Relationship between the posterior cerebral artery and the cisternal segment of the oculomotor nerve.

The aim of this study was to evaluate the relationship between the cisternal segment of the oculomotor nerve and the posterior cerebral artery and its branches. The oculomotor nerve and the posterior cerebral artery of 15 cadaver brains (30 hemispheres) were examined using a surgical microscope. The dorsal portion of the cisternal segment of the oculomotor nerve had a close relationship with the P(1) and P(2) segments of the posterior cerebral artery in 100% of cases, the thalamoperforating arteries in 97%, the collicular arteries in 97%, the short circumferential arteries in 33% and the posterior medial choroidal arteries in 20%. The proximal portion of the nerve had a close relationship with the P(1) segment of the posterior cerebral artery, the thalamoperforating arteries, the collicular arteries and the short circumferential arteries, whereas the distal portion had a close relationship with the P(2) segment of the posterior cerebral artery and the posterior medial choroidal arteries. The oculomotor nerve was perforated by various arteries in different portions. These arteries were the thalamoperforating arteries in 10% of the hemispheres, the collicular arteries in 16% and the short circumferential arteries in 11%. It can be concluded that the dorsal portion of the cisternal segment of the oculomotor nerve has a close relationship with the branches arising from the P(1) and P(2) segments of the posterior cerebral artery. These arteries supply the cisternal segment of the oculomotor nerve.

[Pupil-sparing painful oculomotor neuropathy due to a carotico-cavernous aneurysm]. / Ophtalmoplégie extrinsèque pure douloureuse du nerf moteur oculaire commun révélant un anévrysme de la carotide.

INTRODUCTION: In third cranial nerve palsy, the lack of mydriasis evokes a noncompressive mechanism. Case report. We report a case of a slightly painful, pure extrinsic third-nerve palsy, complete except for the partial ptosis secondary to the compression by an intracavernous carotid aneurysm. Percutaneous endovascular embolization was followed by complete regression of the palsy within 4 weeks. The pupil may have been spared by the mechanism of compression after the separation of the pupillomotor and extrinsic fibers or the ischemia of the third nerve by its arterial trunk lesion. CONCLUSION: This case report underlines that brain radiological explorations are necessary in some third-nerve pupil-sparing palsies.

Oculomotor, trochlear, and abducens nerves penetrated by cerebral vessels. Microanatomy and possible clinical significance.

Twenty formaldehyde-fixed brains were examined under the stereoscopic microscope. In 12 brains (60%), the oculomotor nerves were penetrated by the circumflex mesencephalic artery or by a branch of the perforating vessels of the posterior cerebral artery, either on one side (40%) or on both (20%). In one brain (5%), a particular relationship was noticed between the trochlear nerve and the superior cerebellar artery. The abducens nerves were penetrated by the corresponding pontine veins in three brains (15%). These anatomical findings might have important clinical implications.

Risk factors for ischemic ocular motor nerve palsies.

OBJECTIVE: To identify risk factors associated with neurologically isolated ischemic ocular motor nerve palsies. DESIGN: Case-control study. SETTING: Multispecialty clinic providing primary, secondary, and tertiary care in central and northern Wisconsin. STUDY PARTICIPANTS: After applying strict, predetermined, inclusion and exclusion criteria to the medical records of patients with ocular motor nerve palsies, 65 case patients 50 years of age or older were identified with ischemic ophthalmoplegia. A control subject, matched for sex and exact year of age, was randomly selected for each case patient from individuals undergoing a comprehensive medical evaluation. MAIN OUTCOME MEASURES: Prevalence of potential risk factors in case patients and controls, including diabetes, hypertension, hypercholesterolemia, coronary artery disease, left ventricular hypertrophy, adiposity, tobacco use, prior ocular motor nerve palsy, and hematocrit. Risk factors were assessed using standardized definitions. RESULTS: After adjustment for potential confounding factors, significant risk factors and their associated odds ratios (ORs) and 95% confidence intervals (CIs) were as follows: previously diagnosed diabetes, OR = 5.75 (CI = 1.68 to 19.7); left ventricular hypertrophy, OR = 5.20 (CI = 1.30 to 20.82); and, hematocrit (per percentage increase), OR = 1.35 (CI = 1.13 to 1.61). CONCLUSION: In addition to the generally accepted risk factor of diabetes, left ventricular hypertrophy and elevated hematocrit appeared to be important determinants of ischemic ocular motor nerve palsy. Additional studies should be undertaken to confirm these findings.

Anterior transposition of the inferior oblique. Anatomic assessment of the neurovascular bundle.

Anterior transposition of the inferior oblique insertion has been described as an effective procedure for weakening the inferior oblique and for decreasing dissociated vertical deviation. It has been postulated that this occurs by converting the inferior oblique muscle from an elevator to a depressor. We found histologic, radiologic, and clinical evidence that anterior transposition of the inferior oblique muscle converts it to a depressor by means of the firm posterior attachment of the inferior oblique muscle at the site of its neurovascular bundle. This new functional insertion at the neurovascular bundle created by the anterior transposition allows for the depressor effect seen after this procedure.

Early progression of ophthalmoplegia in patients with ischemic oculomotor nerve palsies.

OBJECTIVE: To describe the frequency and clinical correlates of early progression of ophthalmoplegia in patients with ischemic oculomotor nerve palsies. DESIGN: Cohort survey, case series. SETTING: Multispecialty clinic providing primary, secondary, and tertiary care in central and northern Wisconsin. PATIENTS: Sixteen patients evaluated within 1 week of the reported onset of ischemic oculomotor nerve palsy were identified and followed up prospectively using a standardized ophthalmoplegia grading scheme. All patients were followed up serially until their ophthalmoplegia resolved. MAIN OUTCOME MEASURES: Descriptive analysis of the temporal course of ophthalmoplegia and frequency of progression of deficits. Comparison between the group that had progression of ophthalmoplegia with the group that did not for age, hematocrit, cholesterol level, and adiposity; presence of diabetes, hypertension, hypercholesterolemia, and coronary artery disease; history of stroke; and tobacco use. RESULTS: Eleven (69%) of 16 patients had progression of ophthalmoplegia. The median time between reported onset and peak severity of ophthalmoplegia was 10 days. The only important difference between the progressive and nonprogressive groups was a shorter time to resolution of ophthalmoplegia for the nonprogressive group. CONCLUSIONS: Early progression of ophthalmoplegia occurs often in patients with ischemic oculomotor nerve palsies. The power to find differences between progressive and nonprogressive groups was limited by the small number of patients available for analysis.

Ischaemic oculomotor nerve palsy. Clinical features and vascular risk factors in 23 patients.

Of 61 patients with isolated third nerve palsy, 23 (38%) had the characteristic clinical features of an ischaemic oculomotor nerve palsy. The essential sign of this usually painful disorder of acute onset was a marked discrepancy between complete or severe paresis of the extraocular muscles innervated by the third nerve, and sparing of the pupillary sphincter. All patients had completely recovered within 3 months. Fourteen had a history or on follow-up had other cranial mononeuropathies. Except for two patients, all were above the age of 60 years. Of the 23 cases, 11 had diabetes mellitus and 8 an abnormal glucose tolerance test, while in 4 the latter was normal. Almost all had hypertension and were overweight, and half were smokers. In 18 patients, four or five vascular risk factors were present.

[Paralysis of the 3d cranial nerves in diabetes and common oculomotor vascularization]. / Paralysies de la IIIe paire au cours du diabete et vascularisation du moteur oculaire commun.

The purpose of this paper is to present explanations for various patterns of IIIrd cranial nerve involvement in diabetes mellitsus, based on its vascularisation. Three clinical cases of diabetes with numerous attacks of IIIrd nerve paralysis are reported. The following patterns were observed: (1) isolated; (2) associated with Vth nerve involvement and; (3) associated with invovlement of the Vth, IVth, VIth, and occasionally IInd and VIIth nerves. An anatomical study of IIIrd nerve vascularisation demonstrates three territories which could correspond to the 3 patterns of clinical expression. The arterial branches to the IIIrd nerve give off no collaterals in the posterior region of the circle of Willis. In the supra-cavernous region, vascularisation of the IIIrd nerve may be associated with that of the IVth. Eventually, vascularisation of the IIIrd nerve in the intracavernous region is associated with that of the Vth, IVth, VIth, and occasionally IInd and VIIth cranial nerves. Thus, a painless paralysis of the IIIrd nerve (isolated or associated only with an involvement of the IVth) would predictably be related to a vascular disturbance limited to the first or second portion of this nerve, whereas a painful paralysis of the IIIrd nerve, without or with associated involvement of other cranial nerves, would relate to a vascular distrubance in the intra-cavernous region. The anatomo-clinical relationships that have been presented: (1) support the vascular basis of IIIrd nerve paralysis in diabetes; (2) explain the various clinical patterns of IIIrd nerve involvement in that disorder and; (3) act as a model which can be applied to the study of ischemic pathology in other cranial nerves and other etiologies.

The blood supply of the intracavernous cranial nerves: an anatomic study.

Cranial nerve deficits are the most common complications of cavernous sinus surgery. Often the deficit occurs despite anatomic preservation of the nerve, and ischemic injury is thought to be the cause. A better understanding of the blood supply of these nerves may help to prevent such complications. The authors performed a cadaveric microsurgical study of the intracavernous cranial nerves and their blood supply in 20 cavernous sinuses. The oculomotor nerve received branches from the inferolateral trunk or its equivalent in all specimens (100%). The proximal trochlear nerve received branches from the inferolateral trunk in 80% of the specimens and from the tentorial artery of the meningohypophyseal trunk in 20%. The distal half was supplied by the branches from the inferolateral trunk only. In the region of Dorello's canal, the proximal third of the abducens nerve received branches from the dorsal clival artery of the meningohypophyseal trunk. The middle and distal thirds received branches from the inferolateral trunk. The ophthalmic and proximal maxillary segments of the trigeminal nerve received branches from the inferolateral trunk. The distal maxillary segment was supplied by the artery of the foramen rotundum. In the majority of cases, the medial third of the Gasserian ganglion received branches from both the inferolateral trunk and the tentorial artery. The middle third of the ganglion received branches from either the inferolateral trunk or the middle meningeal artery. Our findings indicate the important role the intracavernous branches of the internal carotid artery play in the blood supply of the intracavernous cranial nerves, and stress the need to preserve these branches to prevent or minimize postoperative deficits.

Anatomy of the extraneural blood supply to the intracranial oculomotor nerve.

AIMS: An anatomical study was undertaken to determine the extraneural blood supply to the intracranial oculomotor nerve. METHODS: Human tissue blocks containing brainstem, cranial nerves II-VI, body of sphenoid, and associated cavernous sinuses were obtained, injected with contrast material, and dissected using a stereoscopic microscope. RESULTS: Eleven oculomotor nerves were dissected, the intracranial part being divided into proximal, middle, and distal (intracavernous) parts. The proximal part of the intracranial oculomotor nerve received extraneural nutrient arterioles from thalamoperforating arteries in all specimens and in six nerves this blood supply was supplemented by branches from other brainstem vessels. Four nerves were seen to be penetrated by branches of brainstem vessels and these penetrating arteries also supplied nutrient arterioles. The middle part of the intracranial oculomotor nerve did not receive nutrient arterioles from adjacent arteries. The distal part of the intracranial oculomotor nerve received nutrient arterioles from the inferior cavernous sinus artery in all 11 nerves and in seven nerves this was supplemented by a tentorial artery arising from the meningohypophyseal trunk. The inferior hypophyseal artery arose from the meningohypophyseal trunk in all 11 cavernous sinuses dissected. CONCLUSION: This study shows a constant pattern to the blood supply of the intracranial oculomotor nerve. It also highlights the close relation between the blood supplies to the intracavernous oculomotor nerve and the pituitary gland.

Isolated atraumatic third nerve palsy: clinical features and imaging techniques.

We have reviewed 34 consecutive patients imaged for an isolated third nerve palsy over a 2-year period. With pupil sparing the third nerve palsy was most often due to ischaemic microvascular disease. The commonest cause of a third nerve palsy with pupillary involvement was a posterior communicating artery aneurysm. Clinical features such as speed of onset, pain and completeness of palsy were not reliable in the diagnosis of either the nature or the location of the cause. Pupillary involvement was however often associated with a compressive lesion. Imaging along the whole course of the nerve is recommended for adequate evaluation.

The neurovascular relationships and the blood supply of the oculomotor nerve: the microsurgical anatomy of its cisternal segment.

The 27 oculomotor nerves were examined after injection of India ink or methylmethacrylate into the vertebral and the internal carotid arteries. The ventral surface of the cisternal segment of the nerve was noted to be in close relationship with the superior cerebellar artery (96.3%) and its pontine (37.0%), mesencephalic (25.9%) and perforating branches (81.5%); the posterolateral pontine artery (70.4%) and its branches; the anterolateral pontine branches (29.6%), and the perforating branches (85.2%) of the basilar artery; the mesencephalic perforating arteries (11.1%) and their peduncular branches (62.9%); the peduncular branches of the diencephalic perforators (11.1%) and the P1 segment (18.5%); and the accessory collicular artery (3.7%). The dorsal surface of the nerve was in close relationships to the P1 and P2A segments (100%) of the posterior cerebral artery and their peduncular branches (22.2%); the posterior communicating artery (100%); the collicular (100%) and the accessory collicular artery (33.3%), and their peduncular (51.8%) or the perforating branches (22.2%); the medial posterior choroidal artery (25.9%) and its branches (11.1%); and the mesencephalic and diencephalic perforating arteries (100%). Vascular penetration was noted in 51.8% of the third nerves. The most common penetrating vessel was the collicular artery (18.5%) and its branches (22.2%). The cisternal segment of the oculomotor nerve was most often supplied by the mesencephalic perforators (88.9%). The authors discuss the possible clinical significance of the obtained anatomic data.

Clinical studies of ocular motility disturbances: Part 2. Risk factors for ischemic ocular motor nerve palsy [corrected].

A case-control study of 46 Japanese patients who were diagnosed by exclusion as having ischemic ocular motor nerve palsy and who exhibited spontaneous recovery within 4 months was done to evaluate the risk factors involved. We also evaluated the association between the number of risk factors and the spontaneous recovery or recurrence periods. Ischemic ocular motor nerve palsy is closely related to diabetes mellitus and coronary artery disease. Patients tended to be obese; many had two or more risk factors. Aging, in combination with two or more risk factors, seems to increase the likelihood of developing this disease. Diabetes mellitus is a particularly significant risk factor for this type of palsy, especially in combination with hypertension.

The neurofibrovascular bundle of the inferior oblique muscle as its ancillary origin.

PURPOSE: To establish that the neurofibrovascular bundle (NFVB) of the inferior oblique muscle (IO) has ligamentous qualities that enable it to function as an ancillary origin to the muscle. Also, to show that the NFVB does function as the ancillary origin for the IO muscle, particularly when recessing and anteriorly transposing its insertion. METHODS: Fresh (no formaldehyde preservative) cadaver and patient eyes were studied anatomically, histologically, and physiologically. Eighteen orbits were dissected to isolate the IO, the inferior rectus (IR), and the NFVB to demonstrate the linear course of the NFVB and its adjacent fibrous bands. The shape of the muscle was documented. Coronal sections of the two whole, intact orbits were analyzed histologically. Light and electron microscopic sections of an autopsy specimen and a surgical specimen were used to evaluate the capsule of the NFVB and the adjacent fibrous bands near the anterior portion of the NFVB and their attachment to the IR and IO muscle capsules. The elastic modulus was measured in six in situ and six in vitro cadaver NFVB specimens and in six in vivo surgical cases at the time of denervation of the NFVB. For additional comparison, four in vitro cadaver superior oblique tendons were similarly tested. Six eyes that developed recurrent IO overaction following an anterior transposition procedure were surgically explored to determine what structure was serving as its ancillary origin. RESULTS: Gross anatomic and microscopic studies showed a linear orientation of the NFVB with adjacent fibrous bands anteriorly joining the IO and IR muscle capsules. The surgical specimens of the anterior portion of the NFVB show about 50% nerve and 50% fibrocollagenous capsule with the collagen fibers aligned parallel to the NFVB. The elastic modulus was highest (stiffest) in surgical specimens of the NFVB and in situ cadaver NFVB, followed by in vitro cadaver NFVB and, finally, in vitro cadaver superior oblique tendon. In patients who have undergone anterior transposition surgery, the NFVB served as the ancillary origin of the IO. CONCLUSIONS: The name of the neurovascular bundle should be changed to the NFVB, since it has a prominent fibrocollagenous capsule and it is encased in fibrous tissue bands anteriorly. The NFVB has a linear course in the orbit from the apex to the IO muscle and is relatively stiff. The associated fibrous band extends posteriorly from the IO muscle capsule, encasing the nerve anteriorly and attaching 3 to 7 mm posteriorly into the capsule of the IR. The NFVB binds the mid posterior portion of the IO posteriorly. Its ligamentous qualities enable the NFVB to function as an ancillary origin for the IO.

Sub total unilateral oculomotor nerve palsy in a Le Fort I osteotomy.

A 35-year-old man developed a pupil sparing palsy of the oculomotor nerve after a standard Le Fort I osteotomy during which there had been more bleeding than usual. No definite cause was found but we suggest that it was caused by ischaemia of the nerve secondary to local injury by haematoma or instrumentation. The anatomical basis for this is discussed.

[Intra-axial involvement of the common oculomotor nerve in mesencephalic infarctions]. / Atteinte intra-axiale du nerf moteur oculaire commun dans les infarctus mésencéphaliques.

Mesencephalic infarcts are rarely limited to the midbrain, and usually extend rostrally to the thalamus. This fact explains why an elective palsy of the oculomotor nerve is exceedingly uncommon in brainstem infarcts. We studied 4 cases with a unilateral infarct apparently restricted to the middle mesencephalon, with intra-axial involvement of the oculomotor nerve. In 2 cases with a fascicular lesion, there was a contralateral hemiparesis or hemi-ataxia, so that it is possible to term them Weber's syndrome and Claude's syndrome. In the 2 other cases, we suggest that a nuclear syndrome of the oculomotor nerve was present, because of bilateral involvement of the rectus superior in both cases, of the levator palpebrae in one case, and of the parasympathetic pupillary fibres in the other, although the infarct was unilateral. There are several clinical variants of the intra-axial syndrome of the oculomotor nerve which can be differentiated according to the uni or bilaterality of the oculomotor palsy, the pupillary disturbances, and the type of associated neurological dysfunction. The nuclear syndrome corresponds to an infarction of the median arterial area, which is directly supplied by the most distal part of the basilar artery. The fascicular syndromes correspond to infarction of the paramedian and intermediolateral areas supplied by the first part of the posterior cerebral artery (basilar communicating or mesencephalic artery). As the paramedian thalamic arteries also originate from the basilar communicating artery, most infarcts also involve the upper midbrain and the thalamus, producing supranuclear oculomotor disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)