Neuroscience 1A: Cerebral Vascular Anatomy PDF

UNIVERSITY OF NORTHERN PHILIPPINES NEUROSCIENCE 1A LC15 CEREBRAL VASCULAR ANATOMY...

UNIVERSITY OF NORTHERN PHILIPPINES NEUROSCIENCE 1A LC15 CEREBRAL VASCULAR ANATOMY COLLEGE OF MEDICINE, BATCH 2026 Transcribers & Editors: Dr. Vida Margarette D. Andal | Dec. 2022 Octaviano, Paringit, Patao, Patricio, Pigar, Quiambao OUTLINE I. INTRODUCTION II. ANTERIOR CIRCULATION A. INTERNAL CAROTID ARTERY B. ANTERIOR CEREBRAL ARTERY C. MIDDLE CEREBRAL ARTERY III. POSTERIOR CIRCULATION A. VERTEBRAL ARTERY B. BASILAR ARTERY C. POSTERIOR CEREBRAL ARTERY IV. CIRCLE OF WILLIS V. CLINICAL CORRELATIONS VI. CEREBRAL VEINS VII. RECALLS I. CEREBRAL VASCULAR ANATOMY Figure 2. Internal Carotid Artery (ICA). Vascular means blood vessels. Arteries of the Brain Carotid sheath acts a cover that encases the internal jugular vein, CN X, o Two internal carotid arteries (anterior circulation) internal carotid artery. o Two vertebral arteries (posterior circulation) Figure 1. Arteries of the brain. II. ANTERIOR CIRCULATION Figure 3. Internal Jugular Vein , CN X and Internal Carotid Artery. A. Internal Carotid Artery Supply your brain INTERNAL CAROTID ARTERY (ICA) SEGMENTS Acts as a gate keeper to make sure you have enough supply of pressure 1. C1 (Cervical) segment to push the blood upward) From the carotid bifurcation, it ascends and perforates the base of Begins at a localized dilatation called the carotid sinus the skull by passing through the carotid canal of the temporal bone. o Carotid sinus o Does not have any branches in the neck (starts at carotid ▪ Baroreceptor that detects blood pressure changes bifurcation, ends at carotid canal). (group of specialized cells that are found intravascularly) o Carotid body ▪ Chemoreceptor that detects acid-base disturbances (signal the body to adjust the acidity of the blood) Page 1 of 17 [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal 3. C3 (Lacerum) segment From the posterior edge of the foramen lacerum (not through it!) to the superior margin of the petrolingual ligament o No branches 4. C4 (Cavernous) segment From the superior margin of the petrolingual ligament, it courses superiorly along the posterior clinoid process of the sphenoid bone, making its way to the anterior clinoid process, before emerging through the roof of the cavernous sinus. o Meningeal artery: supplies the dura mater of the anterior cranial fossa. Anastomoses with the meningeal branch of the posterior ethmoidal artery (severing the meningeal artery will cause Epidural Hematoma). o Inferior hypophyseal artery: supplies the posterior pituitary gland and terminates in the pituitary portal system (carries pituitary hormones to target organs). ▪ Trigeminal ganglion branch ▪ Cavernous sinus branch ▪ Marginal tentorial branch ▪ Basal tentorial branch Figure 4. Internal carotid artery (ICA) and its different segments. 2. C2 (Petrous) segment From the entrance of the carotid canal, traverses superomedial to the posterior edge of the foramen lacerum (2 branches): o Caroticotympanic artery: travels through the tympanic cavity and anastomoses with the anterior tympanic branch of the stylomastoid artery and the maxillary artery (connects internal and internal carotid artery). o Vidian artery/pterygoid artery: courses through the pterygoid canal with the vidian nerve. Anastomoses with a branch of the Figure 6. Cavernous sinus and the cranial nerves passing through it. greater palantine artery. In the cavernous sinus: most medial structure - ICA, most superolateral structure - CN III and CN IV, inferolateral - CN V1 and CN V2, closest to ICA - CN VI Dilatation of ICA will affect CN VI first before CN V 2 and patient will show a physical manifestation of impaired lateral gaze 5. C5 (Clinoid) segment From the proximal dural ring (anterior clinoid process) to the distal dural ring (cavernous sinus roof) o No branches 6. C6 (Ophthalmic/Supraclinoid) segment Called ophthalmic segment since it gives off the very important ophthalmic artery From the distal dural ring to just proximal to the origin of the posterior communicating artery o Superior hypophyseal artery: supplies the infundibulum, median eminence of the hypothalamus and pars tuberalis of the anterior pituitary (in anastamosis with inferior hypophyseal artery of C4) Figure 5. Anatomical segments of the internal carotid artery and their branches. [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal o Ophthalmic artery: passes through the optic canal, enter the orbit and supply its contents (goes in and supplies the eyeball through central retinal artery, which is its first branch) 7. C7 (Communicating) segment Terminal segment of ICA From the proximal origin of the posterior communicating artery to the internal carotid bifurcation o Posterior communicating artery: anastomoses with the posterior cerebral artery to form the Circle of Willis o Anterior choroidal artery: crosses the optic tract to supply the crus cerebri, then recrossing it to supply the lateral geniculate body of the thalamus. It then passes through the choroidal fissure to enter the lateral ventricle and supply the choroid plexus. o Anterior cerebral artery o Middle cerebral artery Figure 8. Medial view of arteries of the brain. ANTERIOR CEREBRAL ARTERY (ACA) SEGMENTS 1. A1 (Precommunicating) segment Between the terminal ICA bifurcation and Acomm. Lies superior to the optic nerve and chiasm. Anastomoses with the contralateral ACA via the anterior communicating artery Sometimes you don’t have A1 segment on one side of the brain, so supply of the medial brain would come from the contralateral side Figure 7. Lateral and anterior view of ICA segments. Internal Carotid Artery (ICA) C1 – Cervical C2 – Petrous C3 – Lacerum C4 – Cavernous C5 – Clinoid C6 – Ophthalmic C7 – Communicating Come, Please Let Children Consume Our Candy B. ANTERIOR CEREBRAL ARTERY Arises from the terminal end of the internal carotid artery (along with MCA) Runs rostrally and caudally where it anastomoses with the ACA of the contralateral side via the Acomm Courses posteriorly along the superior border of the corpus callosum to reach its terminal branches (runs in the deep medial structure) Figure 9. Anterior Cerebral Artery (ACA) segments [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal 2. A2 (Infracallosal/Postcommunicating) segment 4. A4 (Supracallosal) segment After Acomm to the genu of the corpus callosum/origin of the Runs from the body of the corpus callosum anterior to the coronal callosomarginal artery suture o Orbitofrontal branches: supply olfactory cortex, gyrus rectus, o Precuneate artery medial orbital gyrus o Frontopolar artery 5. A5 (Postcallosal) segment o Callosomarginal artery: supplies the frontal lobe, paracentral After passing the coronal suture, travels posteriorly until it reaches its area and some parts of the parietal lobe terminal branches: o Perforating branches to the hypothalamus, septum o Parietal branches pellucidum, anterior commissure, fornix, striatum, corpus o Parieto-occipital branches callosum o Inferior callosal branches o Recurrent artery of Heubner: also known as the medial striate artery or long central artery - may be absent in 3% of the population or duplicated on the same side in 12% of individuals - supplies the head of the caudate nucleus, medial portion of globus pallidus, anterior crus of the internal capsule, anterior hypothalamus Figure 11 & 12. ACA and their location. C. MIDDLE CEREBRAL ARTERY Largest terminal end of the ICA Courses laterally between the frontal and temporal bones, traversing the Sylvian fissure Passes over the posterosuperior surface of the insula where it bifurcates into the superior and inferior trunks Continues to course superoposteriorly to reach the surface of the brain Figure 10. Recurrent Artery of Heubner. 3. A3 (Precallosal) segment Origin of the callosomarginal artery arching above the genu of the corpus callosum, to travel posteriorly along the superior border of the body of the corpus callosum o Pericallosal artery: supplies the medial cerebral surface and the corpus callosum o This is the reason why ACA is in charge of medial cerebral hemisphere Figure 13. Sylvian fissure [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal MIDDLE CEREBRAL ARTERY (MCA) SEGMENTS 1. M1 (Sphenoidal/Horizontal) segment “horizontal” – it courses horizontally From the ICA bifurcation to the point of bifurcation of the MCA between the frontal and temporal lobes (frontal lobe – superior trunk; temporal lobe – inferior trunk) o Lenticulostriate arteries: small perforating branches that supply the basal ganglia, head and body of the caudate, lentiform nucleus, external and internal capsule (common site for hemorrhagic stroke due to high blood pressure – no motor strength, patient is completely paralyzed on one side) o Anterior temporal artery: supply anterior temporal pole of the brain Figure 14. Hemisphere in coronal section showing the segments of the middle cerebral artery (M1 to M4). Figure 16. MCA segment traversing the circular sulcus of insula 2. M2 (Insular) segment M1 is the horizontal segment, once it bifurcates and travels around At the bifurcation of the MCA/genu of the MCA. Divides into superior circular sulcus it is now M2 and becomes M3 if it is in the inner and inferior trunks as it travels in a posterosuperior direction along surface of parietal lobe. the surface of the insula. Terminates at the level of the circular sulcus of the insula. 4. M4 (Terminal/Cortical) segment o Lateral frontobasal artery: lateral part of the orbital surface of Once the M3 portion emerges through the Sylvian fissure to reach the frontal lobe and the inferior frontal gyrus the surface of the brain and travels over the surface of the cerebral hemisphere o Prefrontal artery: anterior aspect of the inferior and middle frontal gyri o Artery of precentral sulcus: posterior aspect of the inferior and middle frontal gyri, Broca’s area, precentral gyrus (primary motor cortex for head, UE and trunk) o Artery of central: pre- and postcentral gyri o Artery of postcentral sulcus: anterior aspect of the parietal lobe and postcentral gyrus (primary somatosensory cortex of head, UE, trunk) o Angular artery: angular and supramarginal gyri of the parietal lobe, posterior part of the superior temporal gyrus, superior part of the lateral surface of the occipital lobe o Middle temporal branches: middle aspect of the superior and middle temporal gyri, primary auditory cortex, Wernicke’s area Figure 15. MCA traversing the Sylvian fissure along the surface of insula. 3. M3 (Opercular) segment Ascend from the circular sulcus of the insula and travel over the inner surface of the parietal (superior trunk) and temporal lobe (inferior trunk) Figure 17. Course of MCA in the interior of the lateral sulcus. [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal III. POSTERIOR CIRCULATION This segement lies before entering the foramina of the transverse process of C6. It starts in the origin in the subclavian artery until it reaches C6. A. VERTEBRAL ARTERIES Branch of the first part of the subclavian artery. 2. V2 (Intraforaminal) segment Pair of ascending arteries that supply the upper part of the spinal cord, Runs an almost vertical course from C6 to C2. it is anterior to the brainstem, cerebellum and posterior cerebrum. trunks of the cervical spinal nerves and is surrounded by the venous Ascends the neck by passing through the foramina in the transverse plexus. processes of the upper six cervical vertebrae. Enters the skull through the foramen magnum and pierces the dura 3. V3 (Extradural/Atlantic) segment mater and arachnoid to enter the subarachnoid space. From the transverse process of C2: Passes upward, forward and medially on the medulla oblongata. o Vertical part: courses superiorly and crosses the root of the C2 Joins the vertebral artery of the opposite side at the level of the lower spinal nerve to enter the transverse foramen of C1 border of the pons to form the basilar artery. o Horizontal part: artery curves medially and posteriorly, passing Between the medulla and pons where the vertebral artery joins forming behind the superior articular process of the atlas and reaches the Basilar artery. Passes through the foramina of the transverse the groove of the upper surface of the posterior arch of the processes of C1 to C6. It is the first branch of the subclavian. atlas. It then passes under the atlantooccipital membrane and enters the vertebral canal. 4. V4 (Intradural/Intracranial) segment Pierces the dura at the base of the skull and courses superiorly over the anterior surface of the medulla oblongata. At the lower border of the pons, it joins the opposite vertebral artery to form the basilar artery. o Anterior spinal artery: originates from two smaller vessels from each vertebral artery. It passes through the foramen magnum and descends along the anterior aspect of the spinal cord to supply its anterior portion. Figure 20. Intradural/intracranial segment of vertebral artery Figure 18. Head and Neck sagittal view showing vertebral arteries ▪ An important branch that your V4 segment gives off. ▪ Have only one anterior spinal artery and is the midline VERTERBRAL ARTERIES SEGMENT structure. 1. V1 (Preforaminal) segment From origin of the vessel, it extends superiorly and posteriorly to pass o Posterior inferior cerebellar artery (PICA): supplies the between the longus colli and anterior scalene muscles to reach the cerebellum. foramina of the transverse process of C6 ▪ PICA course posteriorly to supply the cerebellum specially the inferior parts. ▪ They also have meningeal branches exits the foramen magnum to supply the meninges o Meningeal branches: exits near the foramen magnum to supply the meninges o Medullary artery: supplies the medulla oblongata. Figure 19. Preforaminal segment of vertebral artery [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal BASILAR ARTERY BRANCHES 1. Pontine arteries Emerges from the lateral surface of the Basilar. Can be short and long circumferential arteries. Short branches supply the medial structure of the Pons. Long circumferential branches that supply the lateral side of the Pons 2. Posteromedial (paramedian) arteries Emerges from the distal bifurcation of the basilar Note: Pontine arteries & Posteromedial arteries supply the pons. Figure 24. Inferior view of basilar artery. Figure 21 & 22. Intradural/Intracranial segment of vertebral artery. B. BASILAR ARTERY Main blood vessel for the posterior circulation of the brain. Formed by fusion of the two vertebral arteries at the pontomedullary junction. Travels along a shallow groove along the pons called basilar groove. Terminal bifurcation gives rise to two posterior cerebral arteries (PCA). Runs along the length of the Pons. Figure 25. Brainstem supply by basilar arteries 3. Anterior Inferior Cerebellar Artery (AICA) Arises from the proximal part of the basilar Ventrally related to CN VI, CN VII and CN VIII (emerge from the pontomedullary junction medial to lateral). Travels posterolaterally to supply the inferior aspect of the cerebellum. Anastomoses with the PICA. Supplies anteroinferior surface, flocculus, middle cerebellar peduncle and inferolateral part of the pons. Note: PICA is a branch of the vertebral artery, while the AICA is a branch of the basilar artery. Figure 23. Inferior view of Intradural/Intracranial segment of vertebral artery. [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal 4. Superior Cerebellar Artery (SCA) 6. Posterior Cerebral Arteries (PCA) Arises from the terminal part of the basilar (before it bifurcates) Arises from the bifurcation of the basilar at the superior border of the Caudal to CN III and CN IV (emerges from the midbrain-pons pons. junction). Courses laterally Supplies the occipital lobe, inferomedial surface of Travels around the cerebral peduncles. the temporal lobe, midbrain, thalamus and choroid plexus of the Supplies the superior aspect of the cerebellum, pineal body and pons. third and lateral ventricles. Anastomosis with derivatives of the inferior cerebellar arteries. Terminal branch of the Basilar artery. Anastomoses with the PComm to form the Circle of Willis. Figure 28. Posterior Cerebral Artery (PCA) C. POSTERIOR CEREBRAL ARTERY SEGMENTS 1. P1 (Precommunicating) segment Extends from the basilar bifurcation to the anastomosis with the Pcomm o Thalamic-subthalamic arteries (paramedian thalamic arteries): supply the medial thalamus 2. P2 (Postcommunicating) segment Extends from the anastomosis with the Pcomm to the part of the artery that lies in the perimesencephalic cistern of the posterior border of the lateral aspect of the midbrain o Thalamogeniculate arteries: arises from PComm. Supply the ventrolateral region of the thalamus (also called the Polar Figure 26. Basilar artery branches artery). o Posterior choroidal arteries: supply the posterior region of the 5. Internal Auditory (Labyrinthine) artery thalamus including the pulvinar. May also arise as a branch of SCA, PICA or AICA. o Temporal branches: commonly have an anterior and posterior (Majority of the population it is a branch of Basilar artery) branch (anterior inferior temporal artery, posterior inferior Travels along the internal acoustic meatus with CN VII and CN VIII to temporal artery). Supply the uncus, parahippocampal, medial supply the inner ear. and lateral occipitotemporal gyri. 3. P3 (Quadrigeminal) segment Extends from the posterior border of the lateral aspect of the midbrain to the origin of the parieto-occipital and calcarine arteries. o Occipital branches: usually have a lateral and medial branch. Supply the cuneus, lingual gyrus and posterolateral surface of the occipital lobe. 4. P4 (Calcarine) segment Terminal branches found in the calcarine fissure o Occipitotemporal artery o Calcarine artery: visual cortex, inferior cuneus, part of the lingual gyrus o Parieto-occipital artery: supply the precuneus and cuneus Posterior Cerebral Artery Variants: Fetal (origin) of posterior cerebral artery o Common variant of the PCA o Unilateral incidence of 10%, bilateral 8% o Reduced size of P1 segment, so the Pcomm supplies the blood to PCA (Fetal Pcomm) Figure 27. Internal auditory labyrinth artery o For bilateral fetal PCA, the basilar artery is significantly smaller. [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal Figure 29. PCA variants IV. CIRCLE OF WILLIS Connects the anterior and posterior vascular supply of the brain. Lies in the interpeduncular fossa in the base of the brain. Provides an alternative route for blood flow in the event of a vascular occlusion. Serves as a pressure relief system to accommodate increased blood flow in instances of increased intracranial pressure. If the other side of the brain has an increased pressure, the pressure will dissipate to the other side. For example: If there is an occlusion in Pcomm artery, the blood will direct on the other side via circle of Willis. Serves as backup plan or a detour, so that you can have an alternative Figure 31. The Cerebral vascular arterial system. route in case of vascular occlusion Not everyone has a complete circle of Willis. Because not everyone has an A1 segment on one side or some of us don’t have Pcomm on one side Figure 30. Inferior view of brain showing circle of Willis and neighboring arteries Figure 32 & 33. Radiology and visual presentation of Brain Arterial Vascular System [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal Figure 35. ICA infarction, radiology showing occlusion of ICA B. INTERNAL CAROTID ARTERY (ICA) DISSECTION Layers of the ICA are spontaneously separated, thus compromising blood flow (may be due to blood clot) A tear occurs in the intimal layer creating an intramural hematoma that causes stenosis and eventual thrombus formation May be traumatic or spontaneous May be asymptomatic (If blood clot is small, the blood clot may be compressed if you have high blood pressure) Headache, facial or eye pain, neck pain (carotidynia), Horner syndrome (if hematoma compresses ipsilateral sympathetic nerve fibers). Horner Syndrome – Signs are miosis, ptosis, enophthalmios, dilation of skin arterioles and anhidrosis. All these symptoms result from an interruption of sympathetic nerve supply to the head and neck. Pathologic cause includes lesions (Multiple sclerosis and syringomyelia) in the brainstem or cervical part of the spinal cord. Figure 34. Radiology and visual presentation of Brain Arterial Vascular System V. CLINICAL CORRELATIONS You can have infarctions of arteries (means occlusions of the blood vessels) Can lead to hypoperfusion of the brain A. INTERNAL CAROTID ARTERY (ICA) INFARCTION May affect ACA, MCA and even PCA territories (for fetal PCA) à 2/3 or all of the entire cerebral hemisphere So how it will manifest? Anything that will affect your ACA and MCA. You’ll have contralateral hemiplegia and numbness, contralateral hemianopsia (due to destroyed optic tracts), ipsilateral gaze deviation (due to disruption of frontal eye fields), aphasia (dominant hemisphere), neglect (non- dominant hemisphere), amaurosis fugaux (Transient blindness) due to CRAO-Central retinal artery occlusion. ICA is a big vessel and from its stem is ACA, MCA and even PCA (If you Figure 36. ICA dissection, radiology showing separation of ICA. have a fetal PCA. In fetal PCA the blood supply comes from PComm which is connected to anterior circulation, so when you have problem C. ANTERIOR CEREBRAL ARTERY (ACA) INFARCTION with ICA such as infarction, many arteries are hit/affected like ACA, Unilateral contralateral motor weakness (leg > arm/hand/face) MCA and even PCA.) Unilateral contralateral motor weakness (leg > arm/hand/face) Another problem is what if both of your ACA comes from one side Minimal sensory changes and you don’t have the A1 segment of the other side so you’re not Personality change, emotional lability, memory impairment (because just affecting one hemisphere of the brain because you are also frontal lobe is involved/affected) affecting the ACA territory of other hemisphere. In radiology it is only confined on the medial space. gait apraxia Urinary incontinence (because of the involvement of paracentral lobule) [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal F. MIDDLE CEREBRAL ARTERY (MCA) STROKE SYNDROME Most common artery involved in a stroke Syndromes of infarction depend on which segment is affected 1. MCA STEM (M1) OCCLUSION SYNDROME o Blocks the flow in small, deep penetrating vessels as well as superficial cortical branches o Usually due to embolus o Contralateral hemiplegia, hemianesthesia, homonymous hemianopia, deviation of the head and eyes toward the side of the lesion, global aphasia (left), anosognosia (right) (Since the problem is in the stem, both parietal and temporal lobe are affected. Affected M2 and M3 segments of the superior and Figure 37. ACA infarction. inferior tract). o These are catastrophic strokes; if you have infarct in this area, D. RECURRENT ARTERY OF HEUBNER INFARCTION very likely patient will undergo craniectomy. The neurosurgeon Contralateral arm and facial weakness, dysarthria, hemochorea will have to remove the overlying bone so that there is a space for edema inside the brain. o Usually due to clot/embolus (more often from the heart). The clot or embolus lodges on M1 and not the smaller M2/M3 because the clot or embolus are big, meaning they cannot enter the M2/M3 segment. Figure 38. Artery of Heubner infarction. Figure 41. MCA (M1 Segment) occlusion E. ANTERIOR COMMUNICATING (ACOMM) ARTERY ANEURYSM 2. STRIATOCAPSULAR INFARCTION Most common site for ruptured (23-40%) and unruptured (12- 15%) o Because of lenticulostriate arteries aneurysms o Caudate, putamen, anterior limb of the internal capsule o Hemiparesis involving arm and hand, less in the legs, dysarthria o Homonymous hemianopia (LGN and optic radiations) o No language disturbance or neglect Figure 42. Striatocapsular infarct. 3. MCA SUPERIOR DIVISION INFARCTION o Affects blood supply to the rolandic and prerolandic areas o Dense contralateral sensorimotor deficits in face arms and to lesser extent, the legs o Ipsilateral deviation of the head and eyes o Severe aphasia or Broca’s aphasia (left) Figure 39 & 40. AComm Artery aneurysm.  [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal b. Occlusion of the artery of Percheron o vertical gaze palsy, stupor, coma c. Anteromedial-inferior thalamic syndrome o Occlusion of thalamoperforating branches o Hemiballismus (occlusion of subthalamic nucleus), hemichoreoathetosis 2. CORTICAL PCA OCCLUSION Homonymous hemianopia Cortical areas like P4 segment (Calcarine) 3. BILATERAL PCA OCCLUSION Cortical blindness, unformed visual hallucinations, Anton Syndrome Figure 43. MCA superior division infarction. Cortical blindness, unformed visual hallucinations, Anton Syndrome 4. MCA INFERIOR DIVISION INFARCTION Sometimes called - Top of the basilar syndrome o Affects lateral temporal and inferior parietal lobes Anton Syndrome – patient is blind but deny their blindness. o Wernicke’s aphasia superior quadrantinopia or homonymous hemianopia, visual neglect No problem with retina, optic nerve, lateral geniculate nucleus, optic chiasm, and optic radiation. Problem is in the visual cortex on both sides. Figure 44. MCA inferior division infarction. G. POSTERIOR CEREBRAL ARTERY (PCA) SYNDROMES 1. PROXIMAL PCA OCCLUSION Thalamus area a. Dejerine-Roussy Syndrome o Occlusion of thalamogeniculate arteries o Contralateral sensory loss developing into painful paresthesia, transitory hemiparesis. Figure 45. Brainstem arterial vascular supply INTRA MEDULLARY BRAINSTEM SYNDROMES EPONYM SITE CRANIAL TRACTS INVOLVED SIGNS USUAL CAUSE NERVES INVOLVED WEBER BASE OF III CORTICOSPINAL OCCULOMOTOR VASCULAR SYNDROME MIDBRAIN TRACT PALSY OCCLUSION TUMOR ANEURYSM CLAUDE TEGMENTUM III RED NUCLEUS OCCULOMOTOR VASCULAR SYNDROME OF SUPERIOR PALSY WITH OCCLUSION MIDBRAIN CEREBELLAR CONTRALATERAL TUMOR PEDUNCLES AFTER CEREBELLAR ANEURYSM DECUSSATION ATAXIA TREMOR  [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal BENEDIKT TEGMENTUM III RED NUCLEUS OCCULOMOTOR INFARCT SYNDROME OF CORTICOSPINAL PALSY WITH HEMORRHAGE MIDBRAIN TRACT CONTRALATERAL TUBERCULOMA SUPERIOR CEREBELLAR TUMOR CEREBELLAR ATAXIA PEDUNCLES AFTER TREMOR DECUSSATION CORTICO SPINAL TRACT SIGNS MAY HAVE CHOREOATHETOSIS NOTHNAGEL TEGMENTUM UNILATERAL SUPERIOR OCCULAR TUMOR SYNDROME OF OR CEREBELLAR PALSIES(IV) MIDBRAIN BILATERAL PEDUNCLES PARALYSIS OF GAZE III NYSTAGMUS ATAXIA PERINAUD DORSAL SUPRANUCLEAR PARALYSIS OF PTNEALOMA SYNDROME MIDBRAIN MECHANISM FOR UPWARD GAZE AND OTHER LESIONS UPWARD GAZE ACCOMODATION OF DORSAL OTHER FIXED PUPILS MIDBRAIN STRUCTURES IN HYDROCEPHALUS PERIAQUEDUCTAL INFARCT GRAY MATTER TUMOR CORTICOSPINAL TRACT MILLARD- BASE OF VII AND CORTICOSPINAL FACIAL AND INFARCT GUBIER PONS OFTEN VI TRACT ABDUCENS PALSY TUMOR SUNDROM CONTRALATERAL AND HEMIPLEGIA RAYMOND- SOMETIMES GAZE FOVILLE PALSY TO SIDE OF SYNDROME LESION AVELLIS TEGMENTUM X SPINOTHALAMIC PARALYSIS OF SOFT INFARCT SYNDROME OF MEDULLA TRACT PALATE AND VOCAL TUMOR SOMETIMES CORD DESCENDING CONTRALATERAL PUPILLARY FIBERS, HEMIANESTHESIA WITH BERNARD- HORNER SYNDROME JACKSON TEGMENTUM X, XII CORTICOSPINAL AVELLIS SYNDROME INFARCT SYNDROME OF MEDULLA TRACT PLUS, TUMOR IPSILATERAL TONGUE PARALYSIS WALLENBERG LATERAL SPINAL V, IX, LATERAL IPSILATERAL V, IX, X, OCCLUSION OF SYNDROME TEGMENTUM X, XI SPINOTHALAMIC XI PALSY VERTEBRAL OR OF MEDULLA TRACT HORNER POSTERIOR- DESCENDING SYNDROME INFERIOR PUPILLODILATOR CEREBELLAR CEREBELLAR FIBERS ATAXIA ARTERY SPINOCEREBELLAR CONTRALATERAL TRACT LOSS OF PAIN AND OLIVOCEREBELLAR TEMPERATURE TRACT SENSE Table 1. Intramedullary brainstem syndromes. [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal VI. CEREBRAL VEINS DURAL VENOUS SINUSES Receive (1) unoxygenated blood from the brain through the cerebral Carry unoxygenated blood away from the brain veins and (2) cerebrospinal fluid from the subarachnoid space Have no muscular tissue, have thin walls, possess no valves through the arachnoid villi Found in the subarachnoid spaces Ultimately drain into the internal jugular vein Drain into venous sinuses Veins are lined by endothelium and their walls are thick but are Ultimately drains into the internal jugular vein devoid of muscular tissue External Cerebral veins -drains surface of the brain Valveless EXTERNAL CEREBRAL VEINS INTERNAL CEREBRAL VEINS SUPERIOR CEREBRAL VEINS THALAMOSTRIATE VEIN SUPERFICIAL MIDDLE CEREBRAL VEIN CHOROID VEIN DEEP MIDDLE CEREBRAL VEIN ANTERIOR CEREBRAL VEIN STRIATE VEINS BASAL VEIN EXTERNAL CEREBRAL VEINS DRAINAGE SUPERIOR CEBERAL VEINS SUPERIOR SAGITTAL SINUS SUPERIOR MIDDLE CEREBRAL VEIN CAVERNOUS SINUS (LATERAL SURFACE OF THE CEREBRAL HEMISPHERES) DEEP MIDDLE CEREBRAL VEIN (INSULA) ANTERIOR CEREBRAL VEIN BASAL VEIN → GREAT CEREBRAL STRIATE VEIN VEIN → STRAIGHT SINUS BASAL VEIN INTERNAL CEREBRAL VEINS DRAINAGE THALAMOSTRIATE GREAT CEREBRAL VEIN → STRAIGHT CHOROID VEIN SINUS Figure 47. Dural Venous sinuses. SINUSES Superior sagittal sinus Transverse sinus Confluence of sinuses Occipital sinus Inferior sagittal sinus Straight sinus Cavernous sinus Figure 46. External (A) and Internal(B) cerebral veins [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal CAVERNOUS SINUS THROMBOSIS Life-threatening infection that results as a complication of facial infection, sinusitis, orbital cellulitis, pharyngitis or following traumatic injury or surgery. Bacteria and other pathogens embolize and trigger thrombosis Lead to decreased drainage from the facial vein and superior and inferior ophthalmic veins Fever, headache, periorbital swelling, ophthalmoplegia Cavernous Sinus drains to Petrosal sinus Facial veins drain to cavernous sinus- this is why you don’t want to pop your pimple on your nose. May lead to infection and eventually cavernous sinus thrombosis. Figure 48. Dural Venous sinuses. Tx: antibiotics, anticoagulation Vein of Trolard – Connects superior sagittal sinus and inferior sagittal sinus. Not consistently seen. Inferior sagittal sinus – along the border of corpus callosum or cingulate gyrus CEREBRAL VENOUS THROMBOSIS Complete or partial occlusion of the cerebral venous sinuses or the smaller feeding cortical veins Important cause of stoke in young adults (mean age 33, 2/3 female) Treatment: anticoagulation with heparin, endovascular thrombolysis or thrombectomy, decompressive craniotomy Figure 51. Cavernous Sinus and neighboring structures Figure 49. Cerebral venous thrombosis. Figure 52. Eye proptosis, chemosis and eyelid edema on patient with cavernous sinus thrombosis. Figure 50. Cerebral venous thrombosis clinical presentation. [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal 10. Lenticulostriate arteries are small perforating branches that supply the VII. TEST YOUR SELF external and internal capsule which is a common site for hemorrhagic stroke due to high blood pressure. What will happen to the patient when there is a stroke? 1. A 40-year-old male, presented in the clinic with oculomotor palsy with a. The patient will be completely paralyzed on one side crossed hemiplegia. Examination reveals patient has midbrain vascular b. The patient will have a left homonymous hemianopia occlusion. Which of the following cranial nerve is most likely affected. c. The patient will have an impaired gaze a. CN I d. Th patient will be paralyzed from lower trunk down b. CN X c. CN III d. CN IX 2. This vascular structure connects the anterior and posterior vascular supply of the brain and provide alternative route in case of vascular occlusion. a. Circle of Heubner b. Circle of Willis c. Circle of Trolard d. Circle of Percheron 3. Anastomoses with the PComm to form the Circle of Willis. a. Posterior Cerebral Arteries (PCA) b. Internal auditory (labyrinthine) artery c. Superior cerebellar artery (SCA) d. NOTA 4. This is the Post communicating segment of the posterior cerebral arteries (PCA). a. P1 b. P2 c. P3 d. P4 5. What joins forming the Basilar artery which passes through the foramina of the transverse processes of C1 to C6? a. Angular artery b. Prefrontal artery c. Vertebral artery d. Medullary artery 6. Which statement about the ICA segments is correct: a. The C1 segment ascends and perforates the base of the skull by passing through the carotid canal of the frontal bone. b. The vidian artery/pterygoid artery of C2 courses through the pterygoid canal with the vagus nerve. c. The superior hypophyseal artery that supplies the infundibulum is found on the C4 segment. d. The C4 is also called cavernous segment 7. Cavernous sinus drains to: a. Sagital sinus b. Peduncle sinus c. Geniculate sinus d. Petrosal sinus 8. This artery supplies the dura matter of the anterior cranial fossa and lesion will cause epidural hematoma. a. Inferior Hypophyseal Artery b. Meningeal Artery c. Inferior Meningeal Artery d. Vidian Artery 9. It is the largest terminal end of ICA a. Anterior Cerebral Artery b. Posterior Cerebral Artery c. Middle Cerebral Artery d. Vertebral Artery Answers: 1. C 2. B 3. A 4. B 5. C 6. D 7. D 8. B. 9. C 10. A [NEUROSCIENCE 1A] 01.15 CEREBRAL VASCULAR ANATOMY – Dr. Vida Margarette Andal EXTRA IMAGES FOR REVIEW Image 4. Digital subtraction angiography of cerebral venous sinuses and veins. Images 1, 2, 3. Digital subtraction angiography of cerebral arteries