Internal capsule is supplied by middle cerebral artery. b) Posterior horn of the gray matter of spinal cord is supplied by the posterior cerebral artery. c) Damage to posterior cerebral artery leads to contralateral homonymous hemianopia. d) Contralateral hemisensory and hemiparalysis of arm and face occur due to anterior cerebral artery damage. e) Occlusion of basilar artery results in vertigo. 14) T/F regarding blood supply of brain a) Middle cerebral artery supply leg area of precentral gyrus. b) Mid brain is supplied by posterior cerebral artery. c) Internal capsule is supplied by anterior cerebral artery. d) Posterior cerebral artery obstruction leads to contralateral homonymous hemianopia. e) Occlusion of vertebrobasilar artery gives ipsilateral Horner's syndrome. 15) Blood supply of CNS a) Central arteries are end arteries. b) Central arteries of anterior cerebral artery supply basal ganglia. c) Motor area of the cortex has sole blood supply from middle cerebral arteries. d) Great cerebral vein is formed by thalamostriate and choroidal veins. e) Subdural hemorrhage is caused by damage to middle meningeal vein. 16) T/F regarding blood supply of brain a) Lower part of the posterior limb of the internal capsule is supplied by anterior choroidal artery. b) Internal ear is supplied by posterior cerebral artery. A hemorrhage into the pons is marked by pinpoint pupils and hyperpyrexia. d) Thrombosis of the posterior cerebral artery leads homonymous hemianopia. Thrombosis of anterior cerebral artery leads to paralysis of foot and leg muscles of the opposite side. 17) T/F regarding blood supply to the brain a) Provide by internal carotid and vertebral arteries. b) Anterior limb of the internal capsule is supplied by the branches of anterior choroidal artery. c) All main motor and sensory areas are supplied by middle cerebral artery. Veins in the brain have no valves. Hemi sensory loss mainly in the face and arm is caused due to the rupture of middle cerebral artery. 18) When right middle cerebral artery is damaged a) Hemiparesis of right arm. b) Hemiparesis of left lower limb. Hemiparesis of left arm. d) Left homonymous hemianopia. 可 Right homonymous hemianopia.

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True/False: Blood Supply of the Brain - Complete Answers

Question 13

a) Internal capsule is supplied by middle cerebral artery. TRUE (partially) - The superior aspect of both the anterior and posterior limbs of the internal capsule is supplied by lenticulostriate arteries (branches of the MCA). However, the genu and middle/inferior portions of the posterior limb are supplied by the anterior choroidal artery. So MCA does supply part of the internal capsule, but not all of it. - Localization in Clinical Neurology, 8e

b) Posterior horn of the gray matter of spinal cord is supplied by the posterior spinal artery. FALSE - The posterior horn of spinal cord gray matter is supplied by the posterior spinal artery (a branch of the vertebral artery), NOT by the posterior cerebral artery. The posterior cerebral artery supplies the occipital cortex/brainstem, not the spinal cord.

c) Damage to posterior cerebral artery leads to contralateral homonymous hemianopia. TRUE - PCA occlusion cuts off blood to the occipital (visual) cortex, causing contralateral homonymous hemianopia, typically with macular sparing (since the occipital tip has collateral supply from MCA). - Harrison's Principles of Internal Medicine 22E; Goldman-Cecil Medicine

d) Contralateral hemisensory and hemiparalysis of arm and face occur due to anterior cerebral artery damage. FALSE - ACA damage causes contralateral paralysis and sensory loss primarily of the leg and foot (medial cortical representation). Arm and face deficits are caused by MCA damage. ACA does not supply the face and arm areas of the motor/sensory cortex. - Harrison's Principles of Internal Medicine 22E

e) Occlusion of basilar artery results in vertigo. TRUE - Basilar artery territory includes the brainstem (including vestibular nuclei) and cerebellum. Occlusion causes vertigo, among many other symptoms (diplopia, ataxia, "locked-in" syndrome in full occlusion). - Localization in Clinical Neurology, 8e

Question 14

a) Middle cerebral artery supplies leg area of precentral gyrus. FALSE - The leg area (lower limb motor cortex) is on the medial surface of the hemisphere and is supplied by the anterior cerebral artery (paracentral lobule). The MCA supplies the face and arm areas on the lateral convexity.

b) Midbrain is supplied by posterior cerebral artery. TRUE - The midbrain (mesencephalon) receives its blood supply primarily from the posterior cerebral artery (via its penetrating/perforating branches), along with contributions from the posterior communicating and superior cerebellar arteries.

c) Internal capsule is supplied by anterior cerebral artery. FALSE - The internal capsule is supplied mainly by the lenticulostriate arteries (branches of MCA) for its superior portions, and by the anterior choroidal artery for the genu and inferior posterior limb. The ACA does not directly supply the internal capsule (though Heubner's artery from ACA supplies the anterior limb head of caudate). - Neuroanatomy through Clinical Cases 3rd Ed

d) Posterior cerebral artery obstruction leads to contralateral homonymous hemianopia. TRUE - Same reasoning as 13c. This is the classic PCA syndrome. - Harrison's; Goldman-Cecil

e) Occlusion of vertebrobasilar artery gives ipsilateral Horner's syndrome. TRUE - Lateral medullary (Wallenberg) syndrome from PICA/vertebral artery occlusion produces ipsilateral Horner's syndrome (due to descending sympathetic fiber damage in the lateral medulla), along with ipsilateral facial sensory loss, contralateral body sensory loss, dysphagia, ataxia, and vertigo. - Harrison's Principles of Internal Medicine 22E

Question 15

a) Central arteries are end arteries. TRUE - The central (perforating/lenticulostriate) arteries are functional end arteries - they do not anastomose with each other, which is why their occlusion causes discrete lacunar infarcts with no collateral rescue.

b) Central arteries of anterior cerebral artery supply basal ganglia. PARTIALLY TRUE / MOSTLY FALSE - The medial striate artery (Heubner's artery), a branch of the ACA, supplies the head of the caudate nucleus and anterior putamen (part of basal ganglia). The bulk of the basal ganglia (putamen, caudate body, globus pallidus) is supplied by the lenticulostriate branches of the MCA. - Adams and Victor's Principles of Neurology 12E

c) Motor area of the cortex has sole blood supply from middle cerebral arteries. FALSE - The motor cortex on the lateral surface is supplied by MCA, but the medial motor cortex (paracentral lobule/leg area) is supplied by the ACA. So motor cortex has dual supply from both MCA and ACA.

d) Great cerebral vein (of Galen) is formed by thalamostriate and choroidal veins. TRUE - The great cerebral vein (vein of Galen) is formed by the union of the two internal cerebral veins, each of which is formed by the union of the thalamostriate vein and the choroidal vein. This is classic neuroanatomy.

e) Subdural hemorrhage is caused by damage to middle meningeal vein. FALSE - Subdural hemorrhage is caused by tearing of the bridging (emissary) veins between the cortex and dural sinuses. Damage to the middle meningeal artery (not vein) causes extradural (epidural) hemorrhage.

Question 16

a) Lower part of the posterior limb of internal capsule is supplied by anterior choroidal artery. TRUE - The genu and inferior/middle portions of the posterior limb of the internal capsule are supplied by the anterior choroidal artery (branch of internal carotid). This is well-established. - Harrison's; Adams and Victor's; Goldman-Cecil

b) Internal ear is supplied by posterior cerebral artery. FALSE - The internal ear (labyrinthine/inner ear) is supplied by the labyrinthine artery (internal auditory artery), which is a branch of the anterior inferior cerebellar artery (AICA), itself a branch of the basilar artery. Not the PCA.

c) A hemorrhage into the pons is marked by pinpoint pupils and hyperpyrexia. TRUE - Pontine hemorrhage is classically associated with:

Pinpoint (1 mm) pupils - due to bilateral destruction of sympathetic fibers with preserved parasympathetic input
Hyperpyrexia - due to involvement of descending hypothalamic temperature-regulating pathways
Also: coma, quadriplegia, loss of horizontal eye movements - Plum and Posner's Diagnosis and Treatment of Stupor and Coma

d) Thrombosis of the posterior cerebral artery leads to homonymous hemianopia. TRUE - Confirmed above (same as 13c, 14d).

e) Thrombosis of anterior cerebral artery leads to paralysis of foot and leg muscles of the opposite side. TRUE - ACA supplies the medial cerebral hemisphere (paracentral lobule), which contains the motor and sensory representation for the contralateral leg and foot. ACA occlusion = contralateral leg/foot weakness. - Harrison's Principles of Internal Medicine 22E

Question 17

a) Provided by internal carotid and vertebral arteries. TRUE - The brain receives its entire blood supply from two pairs of vessels: the two internal carotid arteries (anterior circulation) and the two vertebral arteries (posterior circulation, which join to form the basilar artery). These are united by the Circle of Willis.

b) Anterior limb of internal capsule is supplied by branches of anterior choroidal artery. FALSE - The anterior limb of the internal capsule is supplied primarily by the lenticulostriate branches of the MCA and by Heubner's artery (medial striate, from ACA). The anterior choroidal artery supplies the posterior limb (genu and inferior portions), not the anterior limb. - Localization in Clinical Neurology, 8e; Neuroanatomy through Clinical Cases

c) All main motor and sensory areas are supplied by middle cerebral artery. FALSE - As noted above, the leg/foot motor and sensory areas (paracentral lobule, medial surface) are supplied by the ACA. The MCA supplies the face, arm, and trunk areas on the lateral convexity. Not ALL motor/sensory areas are supplied by MCA.

d) Veins in the brain have no valves. TRUE - Cerebral veins, like all veins in the head and neck (and indeed most central veins), have no valves. This allows bidirectional flow and is relevant to spread of infection (e.g., cavernous sinus thrombosis).

e) Hemi-sensory loss mainly in face and arm is caused due to rupture of middle cerebral artery. TRUE - MCA supplies the lateral cortex including the face and arm areas of the sensorimotor cortex and the internal capsule via lenticulostriates. MCA rupture/infarction produces contralateral hemiplegia and hemisensory loss predominantly affecting the face and arm (more than leg). - Adams and Victor's Principles of Neurology 12E

Question 18: When right MCA is damaged

a) Hemiparesis of right arm. FALSE - MCA infarcts cause contralateral deficits. Right MCA damage = left-sided weakness.

b) Hemiparesis of left lower limb. FALSE (or minimal) - The lower limb is primarily supplied by the ACA (medial cortex). MCA mainly causes upper limb and face weakness. Some proximal lower limb involvement can occur but it is NOT the primary finding.

c) Hemiparesis of left arm. TRUE - Right MCA supplies the right lateral motor cortex (face + arm area). Damage = contralateral (left) arm and face hemiparesis. This is the classic finding.

d) Left homonymous hemianopia. TRUE - Right MCA infarction can involve the optic radiations (through the temporal/parietal lobe), causing a left homonymous hemianopia or hemianopic visual field defect contralateral to the side of the lesion.

e) Right homonymous hemianopia. FALSE - Right MCA damage causes contralateral (LEFT) visual field defect, not ipsilateral (right).

Quick Summary Table

Q	a	b	c	d	e
13	T (partial)	F	T	F	T
14	F	T	F	T	T
15	T	Partial T	F	T	F
16	T	F	T	T	T
17	T	F	F	T	T
18	F	F	T	T	F

Sources: Localization in Clinical Neurology 8e, Adams and Victor's Principles of Neurology 12e, Harrison's Principles of Internal Medicine 22e, Goldman-Cecil Medicine, Neuroanatomy through Clinical Cases 3rd Ed, Plum and Posner's Diagnosis and Treatment of Stupor and Coma

19) Regarding blood supply of brain a) Anterior cerebral artery is a small terminal branch of internal carotid artery. b) Middle cerebral artery supplies all the motor area except head area. c) Posterior cerebral artery supplies motor speech area. d) Middle cerebral artery supplies the primary visual area. e) Basilar artery formed by only union of vertebral arteries. 20) True or False a) Cerebral arteries don't anastomoses within brain substances. b) Area for head on precentral gyrus is supplied by middle cerebral artery. c) Basilar artery supplies thalamus. d) Veins of brain have no smooth muscles. e) Subarachnoid hemorrhages usually result from rupture of a congenital aneurism. 21) Hemiplegia follows thrombosis of a) Cortical branches of anterior cerebral artery. b) Cortical branches of middle cerebral artery. C) Central branches of middle cerebral artery. d) Central branches of posterior cerebral artery. e) Posterior inferior cerebellar artery. 22) True or False a) The medial medullary syndrome is caused by thrombosis of the anterior spinal artery. b) Veins in the brain have no valves. c) Transient ischemic attack could not cause permanent disabilities. d) Rupture of meningeal artery can cause sub hemorrhage. e) Abnormalities of cranial blood vessels can be detected by cranial angiograms. 23) Regarding blood supply of brain a) Out of two terminal branches of internal carotid artery, anterior cerebral artery is the larger. b) Circle of Willis is located interpeduncular fossa. Basal vein drains into internal cerebral vein. d) Internal cerebral veins get join to form great cerebral vein at the apex of splenium.

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True/False: Blood Supply of the Brain - Questions 19-23

Question 19

a) Anterior cerebral artery is a small terminal branch of internal carotid artery. FALSE - The ICA divides into two terminal branches: the ACA and the MCA. The MCA is the larger terminal branch, while the ACA is the smaller of the two. The statement is wrong to call ACA "small" while implying it's notable - it is indeed a terminal branch, but the characterization as "small" is misleading and in MCQ context this is considered FALSE because the MCA is the larger terminal branch. - Creasy & Resnik's Maternal-Fetal Medicine; Color Atlas of Human Anatomy Vol 2

b) Middle cerebral artery supplies all the motor area except the head area. FALSE - The MCA supplies the lateral convexity including the motor areas for the face, head, neck, arm, and trunk. It is the leg area (not the head area) that MCA does NOT supply - the leg/foot motor area (paracentral lobule on the medial surface) is supplied by the ACA. So the correct statement would be "MCA supplies all motor area except the leg/foot area."

c) Posterior cerebral artery supplies the motor speech area. FALSE - The motor speech area (Broca's area, area 44/45, inferior frontal gyrus) is on the lateral surface of the frontal lobe and is supplied by the MCA (specifically its upper division). The PCA supplies the occipital lobe, medial temporal lobe, and midbrain.

d) Middle cerebral artery supplies the primary visual area. FALSE - The primary visual cortex (area 17, calcarine cortex) is on the medial surface of the occipital lobe and is supplied by the posterior cerebral artery (calcarine branch). The MCA supplies the lateral occipital cortex (visual association areas) only partially. - Localization in Clinical Neurology, 8e

e) Basilar artery is formed only by union of vertebral arteries. TRUE - The basilar artery is formed solely by the junction of the two vertebral arteries at the pontomedullary junction. No other vessel contributes to its formation.

Question 20

a) Cerebral arteries don't anastomose within brain substance. TRUE - Within the brain parenchyma, the central (perforating) arteries are functional end arteries with no significant anastomoses. There ARE leptomeningeal/cortical anastomoses on the surface between ACA, MCA, and PCA territories, but once the arteries penetrate the brain substance they do not anastomose - which is why deep infarcts (lacunar) cause irreversible damage with no collateral rescue.

b) Area for head on precentral gyrus is supplied by middle cerebral artery. TRUE - The homunculus on the precentral gyrus places the head/face representation on the lateral convexity, which is in MCA territory. The MCA supplies the face, head, neck, arm, and trunk areas of the motor cortex. (Note: this is distinct from the leg area which is supplied by ACA on the medial surface.)

c) Basilar artery supplies thalamus. FALSE (mostly) - The thalamus is primarily supplied by the posterior cerebral artery (thalamoperforating and thalamogeniculate arteries) and the posterior communicating artery. The basilar artery itself supplies the pons, cerebellum (via AICA and SCA), and midbrain. Branches of the PCA (which arises from the basilar tip) do supply the thalamus, but the basilar artery per se is not the direct supplier.

d) Veins of brain have no smooth muscle. TRUE - Cerebral veins have extremely thin walls with virtually no smooth muscle or elastic tissue in their walls, unlike systemic veins. This is a well-established anatomical fact and is why cerebral venous pressure closely reflects ICP changes.

e) Subarachnoid hemorrhages usually result from rupture of a congenital aneurysm. TRUE - The vast majority (75-80%) of spontaneous subarachnoid hemorrhages are due to rupture of berry (saccular) aneurysms, which arise from congenital weakness at arterial bifurcations (typically on the Circle of Willis). - Neuroanatomy through Clinical Cases 3rd Ed; PC Dikshit Forensic Medicine

Question 21: Hemiplegia follows thrombosis of -

a) Cortical branches of anterior cerebral artery. TRUE - ACA cortical branch occlusion causes contralateral leg and foot hemiplegia (monoplegia, really) from infarction of the paracentral lobule/medial motor cortex. This is a form of hemiplegia (specifically involving the contralateral lower limb).

b) Cortical branches of middle cerebral artery. TRUE - MCA cortical branch occlusion causes contralateral hemiplegia predominantly affecting the face and arm (with relative leg sparing) from infarction of the lateral motor cortex.

c) Central branches of middle cerebral artery. TRUE - This is the most "pure" hemiplegia. The lenticulostriate (central) branches of MCA supply the internal capsule (posterior limb), where all corticospinal fibers are tightly packed. Occlusion here (classic lacunar infarct or hypertensive hemorrhage) causes a complete, dense contralateral hemiplegia affecting face, arm, and leg equally - the classic "capsular hemiplegia."

d) Central branches of posterior cerebral artery. FALSE - PCA central branches supply the thalamus and midbrain. Thalamic infarction causes sensory loss (thalamic syndrome), not hemiplegia. Midbrain PCA branch infarction can cause Weber's syndrome (ipsilateral CN III palsy + contralateral hemiplegia from cerebral peduncle involvement), but this is not a straightforward hemiplegia and is not the classic cause.

e) Posterior inferior cerebellar artery (PICA). FALSE - PICA occlusion causes the lateral medullary (Wallenberg) syndrome: vertigo, dysphagia, ipsilateral facial sensory loss, contralateral body sensory loss, ipsilateral Horner's, and cerebellar ataxia. It does not cause hemiplegia because the corticospinal tract in the medullary pyramid (medial medulla) is NOT in PICA territory.

Summary for Q21: a = T, b = T, c = T, d = F, e = F

Question 22

a) The medial medullary syndrome is caused by thrombosis of the anterior spinal artery. TRUE - The medial medullary syndrome (Dejerine syndrome) is caused by occlusion of the anterior spinal artery or paramedian branches of the vertebral artery. It presents with: contralateral hemiplegia (pyramid), contralateral loss of proprioception/vibration (medial lemniscus), and ipsilateral hypoglossal (CN XII) palsy.

b) Veins in the brain have no valves. TRUE - Confirmed again. Cerebral veins are valveless, allowing bidirectional flow. This is important in the spread of septic thrombophlebitis.

c) Transient ischemic attack could not cause permanent disabilities. FALSE - Modern understanding clearly shows that TIAs can and do cause permanent brain injury. DWI-MRI shows that 30-50% of "TIAs" have evidence of true infarction. Furthermore, TIA is a major risk factor for subsequent completed stroke. The old definition (symptoms resolving within 24 hours = no permanent damage) has been replaced. TIAs can leave subtle permanent deficits.

d) Rupture of meningeal artery can cause subdural hemorrhage. FALSE - Rupture of the middle meningeal artery (a branch of the maxillary artery running in the epidural space) causes extradural (epidural) hemorrhage, not subdural hemorrhage. Subdural hemorrhage results from tearing of bridging veins.

e) Abnormalities of cranial blood vessels can be detected by cranial angiograms. TRUE - Cerebral angiography (DSA - digital subtraction angiography) is the gold standard for detecting vascular abnormalities including aneurysms, AVMs, stenoses, vasculitis, and vessel occlusions. CTA and MRA are non-invasive alternatives.

Question 23

a) Out of two terminal branches of internal carotid artery, anterior cerebral artery is the larger. FALSE - The middle cerebral artery is the larger terminal branch of the ICA. The ACA is the smaller of the two. This is confirmed by vessel caliber and territory size - MCA supplies the majority of the lateral hemisphere. - Creasy & Resnik's; Color Atlas of Human Anatomy Vol 2

b) Circle of Willis is located in the interpeduncular fossa. TRUE - The Circle of Willis lies on the base of the brain in the interpeduncular fossa (also called the basal cistern/cisterna interpeduncularis), surrounding the optic chiasm, tuber cinereum, and interpeduncular space. This is the standard anatomical description.

c) Basal vein drains into internal cerebral vein. FALSE - The basal vein of Rosenthal drains into the great cerebral vein (vein of Galen), not into the internal cerebral vein. The internal cerebral veins (formed by thalamostriate + choroidal veins) and the basal veins both drain separately into the great cerebral vein (vein of Galen). Some sources also note the basal vein may drain into the straight sinus directly.

d) Internal cerebral veins join to form the great cerebral vein at the apex of the splenium. TRUE - The two internal cerebral veins run posteriorly in the tela choroidea of the third ventricle and unite just posterior to the pineal gland, at the level of the splenium of the corpus callosum, to form the great cerebral vein (vein of Galen). This then drains into the straight sinus.

Complete Summary Table

Q	a	b	c	d	e
19	F	F	F	F	T
20	T	T	F	T	T
21	T	T	T	F	F
22	T	T	F	F	T
23	F	T	F	T	-

Key Mnemonics to Remember

ICA terminal branches: ACA (smaller) + MCA (larger) - "MCA is the Major branch"
Motor cortex supply: MCA = face/arm/trunk (lateral); ACA = leg/foot (medial paracentral lobule)
Visual cortex: PCA supplies primary visual cortex (calcarine); MCA supplies visual association cortex
Pure/dense hemiplegia: Central branches of MCA (lenticulostriate) → internal capsule → tightest packing of corticospinal fibers
SAH: Berry aneurysm at Circle of Willis bifurcations (congenital weakness)
Epidural vs Subdural: Middle meningeal ARTERY → Epidural; Bridging VEINS → Subdural
Vein of Galen: Formed by union of the two internal cerebral veins at the splenium

Sources: Neuroanatomy through Clinical Cases 3rd Ed, Adams and Victor's Principles of Neurology 12e, Harrison's Principles of Internal Medicine 22e, Color Atlas of Human Anatomy Vol 2, PC Dikshit Textbook of Forensic Medicine

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