NEMS 1.03+1.04 Brain Blood Supply, Meninges, Ventricles, CSF

Question 1

Describe the location of the cavernous sinus and what vein, artery, and nerves travel through this space as well as the normal internal and abnormal external connections and the potential risk this entails.

Answer 1

1. Located along lateral to body of sphenoid bone and sella turcica along with venous blood, internal carotid and many nerves (CN III, IV, V1, V2, and VI).
   a. Normal internal drainage to superior and inferior petrosal sinuses.
   b. Connected externally through facial vein via pteyrgoid plexus and inferior ophthalmic vein (danger triangle)
2. Cavernous sinus thrombophlebitis from infections of superficial face can involve all of these nerves with ocular signs. Can also spread contralaterlaly via intercavernous sinuses.
3. Also potential for other issues p. 14

Question 2

Describe the pathology and presentation of an uncle herniation

Answer 2

1. Uncal Herniations: the uncus is the innermost part of temporal lobe; squeezes through tentorial incisures and puts pressure on brainstem. CN III often disrupted so dilated, non responsive to light (↑ IO pressure). Cranial arteries also at risk. Mydriasis, bradycardia, lethargy, and respiratory abnormalities.

Question 3

Describe the pathology of a cingulate herniation.

Answer 3

1. Cingulate (subfalcine) herniation (most common type): inermst part of frontal lobe scrapes under falx cerebria; may interfere with blood vessels in fortonal lobe. Often occurs with uncal herniation.

Question 4

Describe the pathology of a tonsillar herniation.

Answer 4

1. Tonsillar herniation: brainstem moves down through foramen magnum; causes respiratory and cardiac arrest. Can also stretch branches of basilar artery. Hemorrhage usually fatal.

Question 5

Name each step in the pathway of CSF from production in the lateral ventricles to return to dural sinuses.

Answer 5

1. Lateral Ventricles through Interventricular Foramen (of Monro) 3rd Ventricle through Cerebral aqueduct (of Sylvius) 4th Ventricle then through either…
   a. Median aperture (of Magendie) Cisterna magna (cerebellomedullary cistern)
   b. Lateral Aperture (of Luschka) Pontine cistern
2. Subarachoid space Arachnoid villi Cerebral venous sinuses
   a. Arachnoid granulations are macroscopic collections of arachnoid villi responsible

Question 6

What aspects of the brain are supplied by the vertebral arteries?

Answer 6

Supplies Posterior brain including Brainstem, Cerebellum, Inferior temporal Lobes

Question 7

The anterior spinal artery supplies what regions of the brain/spinal cord?

Answer 7

a. Anterior spinal cord, Anteromedial medulla

Question 8

The PICA supplies what regions of the brain?

Answer 8

a. Inferior cerebellum, Lateral Medulla, Nuclei of pontomedullar junction, Choroid plexus of 4th ventricle.

Question 9

What aspect of the brain is supplied by the internal carotid artery?

Answer 9

anterior brain

Question 10

The ophthalmic artery supplies what region of the brain?

Answer 10

the eye

Question 11

The Anterior Cerebral artery supplies what regions of the brain, and via what branches?

Answer 11

a. Callosomarginal artery: medial and superior portions of frontal and parietal lobes
b. Pericallosal artery: cingulate gyrus and corpus callosum

Question 12

The middle cerebral artery supplies what regions of the brain, and via what branches (2 branches I need to know)

Answer 12

a. Supplies the lateral temporal lobe, lateral parietal lobe, insular lobe, choroid plexus of lateral ventricle (via anterior choroidal artery), basal ganglia (via lateral striate artery)

Question 13

What aspect of the cranium is supplied by the external carotid artery?

Answer 13

supplies tissues external to brain and orbit: includes middle meningeal artery which supplies the meninges.

Question 14

Name the 2 key Deep Veins of the brain and what regions they drain

Answer 14

1. Thalamostriate veins: drain thalamus and basal ganglia of the cerebrum
2. Internal vertebral veins: drain cortical tissue

Question 15

Name 2 Cortical Veins, 2 Anastomotic Cortical Veins, and what regions of the brain each drains.

Answer 15

1. Superficial middle cerebral vein: drains anterior temporal and frontal lobes
2. Basal vein (of Rosenthal)
3. Anastamotic Cortical Veins that connect territories
   a. Superior anastomotic vein (of Trolard): largest cortical vein, drains into superior sagittal sinus
   b. Inferior Anastamotic vein (of Labbe): drains temporal lobe

Question 16

Describe the general flow of blood through the dural sinuses.

Answer 16

1. Superior sagittal sinus: drains down to confluence of sinuses
2. Cavernous sinus: drains to inferior petrosal ( IJV) and superior petrosal ( SiS)
3. Straight Sinus: drains to confluence or Left Transverse sinus
4. Transverse Sinus: drains to sigmoid sinus
5. Sigmoid sinus: drains to IJV