Stroke Presentation Guide
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Blood supply of brain & stroke imaging
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Stroke Presentation Guide
- 1. presentation on STROKE DR SAHIDUL ISLAM PGT, DEPT OF RADIODIAGNOSIS, FAAMCH Moderator DR MK THAKUR PROF & HOD Dept of Radiodiagnosis, FAAMCH DR SANGITA MAHELA Asst Prof Dept of Radiodiagnosis, FAAMCH dr.sahidul@gmail.com
- 2. STROKE IS DEFINED AS EVOLVING COMPLETED TIA
- 3. STROKE RISK FACTORS NON MODIFIABLE • MODIFIABLE o o o o o o o o
- 7. ISCHEMIC STROKE In cerebral ischemia, the affected tissue remains viable although blood flow is inadequate to sustain normal cellular function. In cerebral infarction, frank cell death occurs with loss of neurons, glia, or Both.
- 8. • CEREBRAL BLOOD VOLUME (CBV) 100 • CEREBRAL BLOOD FLOW (CBF) 100 • BLOOD FLOW 0 DEATH OF BRAIN TISSUE <16-18ML/100G INFARCTION <20ML/100GM ISCHEMIA WITHOUT INFARCTION Vasogenic edema cytotoxicedema
- 9. Hyperacute • Early <6HRS,late 6-24 hrs Acute • 24hrs-1 week Subacute • 1-3 weeks chronic • >3 weeks
- 10. • ATHEROSCLEROSIS LACUNAR STROKE • • MCA • • • • •
- 11. STROKE IS THERE A LARGE VESSELS OCCLUSION ?
- 12. BLOOD SUPPLY OF THE BRAIN
- 14. CIRCLE OF WILLIS
- 21. ANTERIOR CIRCULATION INTERNAL CAROTID SYSTEM
- 28. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • • POSTERIOIR CIRCULATION • • • • •
- 29. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • ANTERIOR CHOROIDAL ARTERY • • POSTERIOIR CIRCULATION • • • • •
- 30. ANTERIOR CHOROIDAL ARTERY ANTERIOR CIRCULATION • ANTERIOR CHOROIDAL ARTERY • • POSTERIOIR CIRCULATION • • • • •
- 31. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • ANTERIOR CEREBRAL ARTERY (ACA) • POSTERIOIR CIRCULATION • • • • •
- 32. ANTERIOR CEREBRAL ARTERY • A1 SEGMENT • A2 SEGMENT • A3 SEGMENT
- 33. ANTERIOR CEREBRAL ARTERY • A1 SEGMENT • A2 SEGMENT • A3 SEGMENT
- 34. ANTERIOR CEREBRAL ARTERY • A1 SEGMENT MEDIAL LENTICULOSTRIATE ARTERIES HEUBNER'S ARTERY
- 37. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • • MIDDLE CEREBRAL ARTERY (MCA) POSTERIOIR CIRCULATION • • • • •
- 40. MIDDLE CEREBRAL ARTERY M1 segment – horizontal-extends laterally from the ica bifurcation toward the sylvian fissure M2 segments-insular the postbifurcation mca trunks turn posterosuperiorly in the sylvian fissure, following a gentle curve (the genu or "knee" of the mca) M3 (cortical) segments. The mca branches loop at or near the top of the sylvian fissure, then course laterally under the parts ("opercula") of the frontal, parietal, and temporal lobes that hang over and enclose the sylvian fissureand ramify over the lateral surface of the cerebral hemisphere
- 43. MCA SUPPLY •
- 45. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • • POSTERIOIR CIRCULATION • POSTERIOR CEREBRAL ARTERY (PCA) • • •
- 47. PCA P1 (Precommunicating) Segment. The P1 PCA segment extends laterally from the basilar artery (BA) bifurcation to the junction with the PCoA. P2 (Ambient) Segment. The P2 segment extends from the P1-PCoA junction, running in the ambient (perimesencephalic)cistern as it sweeps posterolaterally around the midbrain. P3 (Quadrigeminal) Segment. The P3 PCA is a short segment that lies entirely within the quadrigeminal cistern P4 (Calcarine) Segment. The P4 segment terminates within the calcarine fissure, where it divides into two terminal PCA trunks P1 P3 P2 P4 P4 P4
- 48. PCA
- 49. PCA
- 52. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • • POSTERIOIR CIRCULATION • POSTERIOR CEREBRAL ARTERY (PCA) • • •
- 53. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • • POSTERIOIR CIRCULATION • • SUPERIOR CEREBELLAR ARTERY (SCA) • •
- 54. MAJOR ARTERIES SUPPLYING BRAIN ANTERIOR CIRCULATION • • • POSTERIOIR CIRCULATION • • SUPERIOR CEREBELLAR ARTERY (SCA) • ANTERIOR INFERIOR CEREBELLAR ARTERY (AICA) • POSTERIOR INFERIOR CEREBELLAR ARTERY (PICA)
- 56. SUPERIOR CEREBELLAR ARTERY whole superior surface of the cerebellar hemispheres down to the great horizontal fissure superior vermis dentate nucleus most of the cerebellar white matter parts of the midbrain superior cerebellar peduncle middle cerebellar peduncle
- 57. ANTERIOR INFERIOR CEREBELLAR ARTERY middle cerebellar peduncle inferolateral portion of the pons flocculus anteroinferior surface of the cerebellum cranial nerves VII and VIII
- 58. POSTERIOR IINFERIOR CEREBELLAR ARTERY It has a variable territory depending on the size of the AICA (AICA-PICA dominance). Typically it supplies: posteroinferior cerebellar hemispheres (up to the great horizontal fissure) • cerebellar tonsils: 85% of the time • biventral lobule: 80% • nucleus gracilis: 85% • superior semilunar lobule: 50% inferior portion of the vermis lower part of the medulla: 50% inferior cerebellar peduncles
- 67. BASAL GANGLIA
- 68. VENOUS DRAINAGE OF BRAIN • The cerebral venous system, somewhat unlike the majority of the rest of the body, does not even remotely follow the cerebral arterial system. • Cerebral veins have thin walls with no muscular tissue and possess no valves. • They emerge from the brain and lie in the subarachnoid space, coursing over the surface of the brain, aggregating into larger channels until they pierce the arachnoid mater and the meningeal layer of the dura mater and drain into the dural venous sinuses.
- 69. Cerebral veins Superficial veins Deep veins DURAL VENOUS SINUSES IJV
- 70. Cerebral veins Superficial veins The superficial venous system is comprised of the sagittal sinuses and cortical veins. The cortical veins course along the cortical sulci, drain the cortex and some of the adjacent white matter. There are numerous cortical veins, and most of them are unnamed; large cortical veins can be identified according to their locations, the cortical venous system can be subdivided into • superficial middle cerebral vein (Sylvian vein) • superior anastomotic vein (of Trolard) • inferior anastomotic vein (of Labbé)
- 71. Cerebral veins Deep veins The deep venous system consists of the lateral sinuses, sigmoid sinuses, straight sinus and draining deep cerebral veins (subependymal and medullary veins). medullary veins: they are numerous and originate 1-2 cm below cortical gray matter and pass through deep medullary white matter and drain into subependymal veins. The medullary veins are arranged in a wedge-shaped manner and distributed at a right angle to subependymal veins. subependymal veins: they receive medullary veins and aggregate into greater tributaries, mainly into septal veins, thalamostriate veins, internal cerebral veins, basal vein of Rosenthal and vein of Galen.
- 72. DURAL VENOUS SINUSES venous channels located intracranially between the two layers of the dura mater (endosteal layer and meningeal layer). They can be conceptualised as trapped epidural veins. Unlike other veins in the body, they run alone, not parallel to arteries. PAIRED • superior sagittal sinus • inferior sagittal sinus • straight sinus • occipital sinus • intercavernous sinus UNPAIRED • transverse sinus • sigmoid sinus • superior petrosal sinus • inferior petrosal sinus • cavernous sinus • sphenoparietal sinus • basilar venous plexus
- 73. The superior sagittal sinus (SSS) is the largest dural venous sinus. As the name suggests, it runs in a sagittal plane from the anterior aspect of the falx cerebri at the foramen cecum to its termination at the confluence of sinuses at the occipital protuberance, where it usually proceeds rightward and into the right transverse sinus. DURAL VENOUS SINUSES SUPERIOR SAGITAL SINUS
- 74. DURAL VENOUS SINUSES SUPERIOR SAGITAL SINUS INFERIOR SAGITAL SINUS The inferior sagittal sinus is one of the dural venous sinuses and runs along the inferior (free) edge of the falx cerebri. It runs from anterior to posterior, the same as the superior sagittal sinus, and drains into the straight sinus.
- 75. DURAL VENOUS SINUSES SUPERIOR SAGITAL SINUS INFERIOR SAGITAL SINUS STRAIGHT SINUS The straight sinus is one of the main dural venous sinuses and is found at the junction between the falx cerebri and the tentorium cerebelli and is triangular in cross-section.
- 76. Transverse sinus Sigmoid sinus Superior petrosal sinus Inferior petrosal sinus Cavernous sinus Sphenoparietal sinus Basilar venous plexus The paired left and right transverse sinuses are major dural venous sinuses and arise from the confluence of the superior sagittal, occipital and straight sinuses at the torcular herophili (confluence of sinuses)
- 77. Transverse sinus Sigmoid sinus Superior petrosal sinus Inferior petrosal sinus Cavernous sinus Sphenoparietal sinus Basilar venous plexus The sigmoid sinus is a paired structure and one of the dural venous sinuses. It is the continuation of the transverse sinus (which is similarly variable in size) and becomes the sigmoid sinus as the tentorium ends. It is here that the sinus receives the superior petrosal sinus
- 78. Transverse sinus Sigmoid sinus Superior petrosal sinus Inferior petrosal sinus Cavernous sinus Sphenoparietal sinus Basilar venous plexus drains the cavernous sinus. It courses posterolaterally to drain into the sigmoid sinus at the continuation of the transverse sinus. It runs along the superior aspect of the petrous temporal bone
- 79. Transverse sinus Sigmoid sinus Superior petrosal sinus Inferior petrosal sinus Cavernous sinus Sphenoparietal sinus Basilar venous plexus a plexus of venous channels rather than a true sinus and drains blood from the cavernous sinus to the jugular bulb through the jugular foramen
- 80. Transverse sinus Sigmoid sinus Superior petrosal sinus Inferior petrosal sinus Cavernous sinus Sphenoparietal sinus Basilar venous plexus • located on either side of the pituitary fossa and body of the sphenoid bone between the endosteal and meningeal layers of the dura. • It spans from the apex of the orbit to the apex of the petrous temporal bone. It receives venous blood from • inferior and superior ophthalmic veins • intercavernous sinus • sphenoparietal sinus • superficial middle cerebral vein
- 92. VARIANTS hypoplasia of one or both PCOM ~30% (range 25-34%) hypoplastic/absent A1 segment of ACA ~15% (range 10-15%) absent or fenestrated ACOM ~12.5% (range 10-15%) origin of PCA from the ICA with absent/hypoplastic P1 segment (fetal PCA) ~20% (range 17-25%) infundibular dilatation of the PCOM origin ~10% (range 5- 15%)
- 93. TO BE CONTINUED….. PART II IMAGING IN STROKE Thank You
Hinweis der Redaktion
- Gme.I m going to present a seminar on STROKE. I have divided the topic into two parts. I am beginning with part 1 today.
- evolving STROKE:A stroke in which focal neurological deficits worsen with time. COMPLETED STROKE:A stroke in which the focal neurological deficits persists & donot worsen with time. TIA-A clinical syndrome of rapid onset of focal deficits of brain function, which resolves with in 24 hours,regardless of whether there’s imaging evidence of new permanent brain injury.
- Depending on the factor of how blood supply is compromised causing stroke, we have Ischemic or hemorrhagic stroke. Ischemic -85% hemorrhagic -5% --among ischemic embolic events are commoner.
- In ischemic – narrowing of a blood vessel or a clot blocking a vessel compromises blood supply to an area in the brain resulting into tussue damage. In hemorrhagic stroke – rapture or leakage of blood into the brain tissue cause the damage.
- The distinction between cerebral ischemia and cerebral infarction is subtle but important
- 2 more phenomena involving with stroke pathophysiology is Vasogenic edema & cytotoxic edema. Vasogenic- Vasogenic cerebral edema refers to a type of cerebral edema in which the blood brain barrier (BBB) is disrupted--commonly seen in brain tumors,abcess & hemorrhage. Cytotoxic edema on the other hand most commonly seen in cerebral ischemia, in which extracellular water passes into cells, resulting in their swelling. I will elaborate both while discussiong stroke imaging.
- Since time is a cruicial factor in stroke so, clinically classification is done based on CHRONOLOGY which is very much important in diagnosis too.
- Restrictions in blood flow may occur from vessel narrowing (stenosis), clot formation (thrombosis), blockage (embolism) or blood vessel rupture (hemorrhage). Lack of sufficient blood flow (ischemia) affects brain tissue and may cause a stroke in the particular area depending on the vessel involved. So , through understanding of the of the arterial system is essential before going deeper into stroke.
- An understanding of brain arterial vascular territories is important in understanding stroke and complications Although one could be excused for thinking that within the brain, such a carefully organized organ, blood supply would be constant, the truth is that a great deal of variety exists. Two main factors contributing to this fact is- circle of Willis anatomy and normal variants intrinsic variability in the extent of tissue each main branch supplies As a result, different sources will have surprisingly different diagrams and descriptions. What is presented here is a general ball-park scheme, with a brief description of the main branches and anatomy.
- The intracranial circulation can be conveniently divided into anterior and posterior circulation, on the basis of internal carotid artery and vertebral artery supply
- The Circle of Willis is an arterial polygon (heptagon) formed as the internal carotid and vertebral systems anastomose around the optic chiasm and infundibulum of the pituitary stalk in the suprasellar cistern. This communicating pathway allows equalization of blood-flow between the two sides of the brain, and permits anastomotic circulation, should a part of the circulation be occluded.
- Both the vertebral arteries ascends upward through foramen in the transverse process of cervical vertebra & enters the cranial cavity through foramen magnum. Then RT & LT vertebral artery fuses to form basilar artery.
- Lateral view showing both vertebral artery joing together at pontomedullary junction & going up as basilar artery.
- Schematic diagram showing different branches of the vertebra-basilar artery. We can see that both vertebral arteries before fusion as basilar artery supplies the spinal cord also. While going up it is supllying various parts of the hindbrain ; we will get the individual branches in awhile.
- In this view we can see few branches of vertebrobasilar system--- 1ST BR -
- SO from posterior circulation we get these major arterial branches.
- The aortic arch gives rise to the brachiocephalic artery, from which subsequently stems the right common carotid artery; the left common carotid artery branches off the aortic arch just downstream the brachiocephalic trunk.
- The left and right common carotid arteries run along parallel to each other and divide near the angle of the mandible to the external and internal carotid arteries. The external carotid supplies the face and neck branching off immediately, while the internal carotid arteries do not branch until the origin of the ophthalmic artery bilaterally. Subsequently, the internal carotid arteries bifurcate onto the anterior and middle cerebral arteries, on each internal carotid artery.
- The anterior choroidal artery arises from the distal part of the internal carotid artery, distally from the origin of the posterior communicating artery. supplies the crus cerebri of the midbrain, lateral geniculate body, choroid plexus of the lateral ventricles and third ventricle, globus pallidus, caudate nucleus, amygdala, hypothalamus, red nucleus, substantia nigra, posterior limb of the internal capsule, optic tract, hippocampus
- The anterior choroidal artery arises from the distal part of the internal carotid artery, distally from the origin of the posterior communicating artery. supplies the crus cerebri of the midbrain, lateral geniculate body, choroid plexus of the lateral ventricles and third ventricle, globus pallidus, caudate nucleus, amygdala, hypothalamus, red nucleus, substantia nigra, posterior limb of the internal capsule, optic tract, hippocampus
- terminal branch of the internal carotid artery. Supplies the medial aspect of the brain. It may be divided into 2 or 3 segments, A1 A2 A3
- A1-horizontal, A2-vertical, A3-callosal
- A1- inferior parts of the head of the caudate and the anterior limb of the internal capsule A2- genu of corpus callosum A3-medial portions of frontal lobes, superior medial part of parietal lobes, anterior part of the corpus callosum
- A1- inferior parts of the head of the caudate and the anterior limb of the internal capsule A2- genu of corpus callosum A3-medial portions of frontal lobes, superior medial part of parietal lobes, anterior part of the corpus callosum
- Summerise the ant cerebral artery supply– it supplies major portion of the medical aspect of frontal lobe and outer cortex of later frontal lobe……xxxxACA vascular territory (green) includes the anterior two-thirds of the medial surface of the hemisphere ſt, a thin strip of cortex over the top of the hemisphere vertex , and a small wedge along the inferomedial frontal lobe
- Graphic reltnship of ACA to underlying brain. A2 segment ascends in front of 3rd ventricle. A3 curves around corpus callosum genu. Pericallosal , callosomarginal arteries ſt are major terminal ACA branches. (8-13) Sagittal MIP of CTA shows A2 segments of both ACAs ſt ascending in interhemispheric fissure in front of 3rd ventricle, A3 segments curving around corpus callosum genu.
- The middle cerebral artery (MCA) is one of the three major paired arteries that supply blood to the brain. The MCA arises from the internal carotid artery as the larger of the two main terminal branches (the other being the anterior cerebral artery), coursing laterally into the lateral sulcus where it branches to perfuse the cerebral cortex.
- Submentovertex graphic depicts the MCA and its relationship to adjacent structures. Note the horizontal (M1) segment and the genu with bifurcation into M2 branches. (8-17) Coronal graphic shows the lateral lenticulostriate arteries , M2 segments over the insula , M3 segments running laterally in the sylvian fissure, and (cortical) branches ſt coursing over the lateral surface of the hemisphere. The lateral lenticulostriate arteries arise from the proximal middle cerebral artery (MCA), usually from M1 segment, more rarely from the postbifurcation or M2 segment. They supply the lateral portion of the putamen and external capsule as well as the upper internal capsule. Note that medial lenticulostriate arteries, which arise more proximally, originating from A1 ACA segment.
- M1 segment extends from the ending of the internal carotid artery, perforating the brain up to its division. The M2 segment bifurcates or occasionally trifurcates. It travels laterally to the Sylvian fissure, and its branches end in the cerebral cortex. The M3 segment travels externally through the insula into the cortex.
- Its penetrating branches supply most of the lateral basal brain
- The middle cerebral artery territory is the most commonly affected territory in a cerebral infarction, due to the size of the territory and the direct flow from internal carotid artery into the middle cerebral artery, providing the easiest path for thromboembolism. ACA territory infarcts are less common because if the A1 segment is occluded there is generally enough collateral flow via the contralateral A1 segment to supply the distal ACA territory 2.
- The two posterior cerebral arteries (PCAs) are the major terminal branches of the distal basilar artery .it courses from basilar towards the occiput. PCA curls around the cerebral peduncle & passes above the tentorium to supply the posteromedial surface of the temporal lobe & the occipital lobe. The visual cortex responsible for contralateral field of vision lies in its territories.
- 1.P1 segment lies above the oculomotor nerve (CN III) and has perforating branches (the posterior thalamoperforating arteries) that course posterosuperiorly in the interpeduncular fossa to enter the undersurface of the midbrain. 2. The P2 segment lies above the tentorium and the cisternal segment of the trochlear nerve (CN IV). Two major cortical branches—the anterior and posterior temporal arteries—arise from the P2 PCA segment and pass laterally toward the inferior surface of the temporal lobe 3. It begins behind the midbrain and ends where the PCA enters the calcarine fissure of the occipital lobe 4. The medial trunk gives off the medial occipital artery, parietooccipital artery, calcarine artery, and posterior splenial arteries, whereas the lateral trunk gives rise to the lateral occipital artery
- Lateral graphic depicts the PCA ſt above and the superior cerebellar artery below the oculomotor nerve . Perforating , choroidal , and cortical st PCA branches are also shown.
- 1, basilar artery (BA); 2, superior cerebellar artery (SCA); 3, posterior cerebral artery (PCA); 4, thalamosubthalamic arteries; 5, posterior communicating artery; 6, internal carotid artery; 7, polar artery of thalamus; 8, posterior choroidal artery; 9, thalamogeniculate artery; 10, anterior inferior temporal artery; 11, posterior inferior temporal artery; 12, occipitotemporal artery; 13, calcarine arteries; 14, occipitoparietal artery.
- The PCA supplies most of the inferior surface of the cerebral hemisphere, with the exception of the temporal tip and frontal lobe. It also supplies the occipital lobe, posterior onethird of the medial hemisphere and corpus callosum, and most of the choroid plexus (8-23). Penetrating PCA branches are the major vascular supply to the midbrain and posterior thalami
- One important issue with PCA is its variation. A common normal variant is the "fetal" origin of the PCA. Here the proximal PCA arises from the ICA instead of from the basilar bifurcation. "Fetal" PCA origin is seen in 10-30% of cases. This variant is easily recognized on CTA, MRA, and DSA this can produce substantial left-right asymmetry on perfusion imaging. Knowledge of this common normal variant is essential, as such asymmetry can mimic cerebrovascular pathology.
- Actually We can discuss these three arteries together due to their origin from vertebrobasilar system & common posterior fossa supply. We already discussed that The vertebrobasilar system consists of the two vertebral arteries (VAs), the basilar artery (BA), and their branches. Each VA arises from the ipsilateral subclavian artery and courses posterosuperiorly to enter the C6 transverse foramen. they enters cranial cavity through foramen magnum courses superomedially behind the clivus and in front of the Medulla. The two VAs unite at or near the pontomedullary junction to form the BA. The BA courses superiorly in the prepontine cistern, lying between the clivus in front and the pons behind. It terminates in the interpeduncular fossa by dividing into the two posterior cerebral arteries
- Now if we draw a schematic diagram to show the origin of SCA. AICA & PICA
- superior cerebellar arteries (SCAs) originate from each side of the distal BA, course laterally below CN III, then curve posterolaterally around the midbrain just below the tentorium (8-25). SCA branches ramify over the surface of the superior cerebellum and upper vermis, curving into the great horizontal fissure…gap SCA is rarely absent, it is frequently duplicated: unilateral duplication: 28% bilateral duplication: 8%
- The AICA arises from the proximal BA and courses ventromedially to CNs VII and VIII, frequently looping into the internal auditory meatus. Gap. 99% of AICAs arise from the basilar artery, but where along the vessel is variable: 75% lower third 16% middle third 9% vertebrobasilar junction
- The posterior inferior cerebellar artery (PICA) arises from the distal VA, curves around/over the tonsil, and gives off the perforating medullary, choroid, tonsillar, and inferior cerebellar branches. It is the most variable and tortuous cerebellar artery. Its origin is highly variable: ~20% arise extracranially, inferior to the foramen magnum 10% arise from the basilar rather than vertebral artery 2% bilaterally absent occasionally loops around the cerebellar tonsil. Gap--AICA-PICA dominance refers to the principle that the cerebellar vascular territory supplied by the anterior inferior cerebellar artery and posterior inferior cerebellar artery have a reciprocal arrangement. That is the size of the AICA and the subsequent territory it supplies is inversely proportional to that of the PICA, and vice versa.
- At the level of extrem vertex,--- Yellow- ACA supplying medial part of the frontal and the parietal lobe. Red-The cortical branches of the MCA supply the lateral surface of the hemisphere, except for the inferior part of the temporal lobe (posterior cerebral artery - Blue).
- Level of centrumsemiovale---Blue- Cortical branches of the PCA supply the inferomedial part of the temporal lobe, occipital pole,
- Superior basal ganglia ---Pink- AchA supplying part of the hippocampus, the posterior limb of the internal capsule & choroid plexuses. Purple- lateral LSA' s are deep penetrating arteries of the (MCA) supplying most of the basal ganglia. Blue- PCA branching off as Posterior thalamoperforating arteries from P1 seg & supplying the thalamus
- Superior Part of Lateral ventricle– showing only ACA, MCA PCA territories
- The brainstem--- Just aboveOrange- medial LSA' s arising from the ACA usually from A1 segment . Heubner's artery is the largest of the medial lenticulostriate arteries and supplies the anteromedial part of the head of the caudate and anteroinferior internal capsule
- AT the level of brain stem.. SCA appearing in the superior part of cerebellum.
- At the level of inferior temporal lobe--- Green- basilar artery supplying medulla & part of the pons below..
- At the level of cerebellopontine angle--- SCA supplying the entire superior part of cerebellum, Green- Basilar supllying pons at this level. Light Green- We can see AICA coming out covering the anterior aspect of cerebellum. On the behind PICA is supplying inferior occipital surface of the cerebellum . One very interesting point is AICA & PICA are in equilibrium in respect of territories.---The larger the PICA territory, the smaller the AICA and viceversa.
- I would like to mention blood supply of the basal ganglia which is little confusing. Basal ganglia are a group of grey matter nuclei in the deep aspects of the brain that is interconnected with the cerebral cortex, thalami and brainstem.
- superficial (cortical) deep (subependymal)
- Furthermore, they are valveless, allowing for bidirectional blood flow in intracranial veins. It is also important to note that the draining territories of intracranial veins are different from those of major cerebral arteries. Together the dural venous sinuses form the major drainage pathways from the brain, predominantly to the internal jugular veins
- It receives venous blood from the cortical veins through the cerebral hemispheres. Anatomical variation is very frequent like duplication hypoplasia etc.
- It receives tributaries from the falx itself as well as some small veins from the medial surface of the cerebral hemispheres.
- The straight sinus is one of the main dural venous sinuses and is found at the junction between the falx cerebri and the tentorium cerebelli and is triangular in cross-section. It receives the inferior sagittal sinus and the vein of Galen at its anterior end and some superior cerebellar veins along its course, and runs posteroinferiorly towards the confluence of sinuses.
- On each side, the transverse sinus then runs in the lateral border of the tentorium cerebelli and grooves the occipital and squamous temporal bones. They terminate in the sigmoid sinus just as it receives the superior petrosal sinus from the cavernous sinus. In turn, the sigmoid sinuses continue as the jugular bulbs in the skull base.
- On each side, the transverse sinus then runs in the lateral border of the tentorium cerebelli and grooves the occipital and squamous temporal bones. They terminate in the sigmoid sinus just as it receives the superior petrosal sinus from the cavernous sinus. In turn, the sigmoid sinuses continue as the jugular bulbs in the skull base.
- On each side, the transverse sinus then runs in the lateral border of the tentorium cerebelli and grooves the occipital and squamous temporal bones. They terminate in the sigmoid sinus just as it receives the superior petrosal sinus from the cavernous sinus. In turn, the sigmoid sinuses continue as the jugular bulbs in the skull base.
- On each side, the transverse sinus then runs in the lateral border of the tentorium cerebelli and grooves the occipital and squamous temporal bones. They terminate in the sigmoid sinus just as it receives the superior petrosal sinus from the cavernous sinus. In turn, the sigmoid sinuses continue as the jugular bulbs in the skull base.
- Unlike other dural venous sinuses, it is divided by numerous fibrous septa into a series of small caves, which is where its name is derived from. The normal lateral wall should be either straight or concave.----- CAVERNOUS SINUS is related to a lot of impo structures- MCA, OPTIC CHIASMA, orbital apex,pituitary fossa & gland etc