Blood supply & drainage Flashcards
Which structures form the blood-brain barrier?
What is its function?
- endothelium of capillaries w/ tight junctions
- underlying basal membranes
- processes of astrocytes
⇒ protection of neurotoxic substances/potential neurotransmitters from the blood
What are neurohemal organs?
Examples.
circumventricular organs w/ interrupted blood-brain barrier due to
- secretory (pituitary) function
- sensory (area postrema) function
Describe the pathway of the 4 parts of a. carotis interna.
- pars cervicalis → base of the skull (acc. by n. vagus, v. jugularis int.)
- pars petrosa (C5) through canalis caroticus
- pars cavernosa (C4 - C3) in sinus cavernosus, forms S-shaped siphon caroticum
- pars cerebralis (C2 - C1) pierces dura mater, gives off 4 final cerebral branches in cisterna carotica

Why is pars cavernosa of a. carotis int. clinically important?
can exert pressure on all nn. located in/around sinus cavernosus
→ possible damage in case of aneurysm
What are the branches of a. carotis int.?
pars cervicalis: -
pars petrosa: aa. caroticotympanicae
pars cavernosa:
- a. hypophysialis inf. → pituitary
- a. meningea centralis → tentorium cerebelli
- rr. gangilionares trigeminales, rr. marginalis tentorii
pars cerebralis:
- a. ophtalmica through canalis opticus → eye, paranasal sinuses, anastomosis w/ a. facialis
- a. hypophysialis sup. → pituitary
- aa. encephali
- r. meningeus
What are the branches of aa. encephali (=a. carotis int.)?
- a. communicans post. forms anastomosis in circle of Willis
- a. choroidea ant.
- a. cerebri ant. part of circle of Willis
- a. cerebri med. part of circle of Willis
cf. circle of Willis drawings
A. carotis is after the aa. coronaria the artery second most affected by atherosclerosis.
What are possible consequences?
- contralateral paralysis due to insufficient supply of motor and premotor cortex
- sensitive disorders due to insufficient supply of sensitive cortex
- speech disorders
- visual disorders due to insufficient supply of retina by a. ophthalmica
Where are all aa. of arterial circle of Willis located?
Clinical relation?
spatium subarachnoideum
→ in case of aneurysms blood can be detected in the liquor
⇒ heavy pain due to meningeal irritation + spasms of brain supplying aa., always life-threatening
´
1a - e

1a) a. carotis int. - pars petrosa (C5)
1b) a. carotis int. - pars cavernosa (C4)
1c) a. carotis int. - siphon caroticum (C3)
1d) a. carotis int. - pars cerebralis, cisterna carotica (C2)
1e) a. carotis int. - pars cerebralis (C1)
2 - 6

2) chiasma opticum
3) a. ophthalmica
4) a. cerebri ant.
5) a. communicans a.
6) a. cerebri med.
7 - 11
For clarification: #9 is a branch of #1e

7) a. choroidea ant.
8) a. communicans post.
9) a. hypophysialis sup.
10) a. hypophysialis inf.
11) a. cerebri post.
12 - 16

12) a. sup. cerebelli
13) a. basilaris
14) a. inf. ant. cerebelli
15) a. labyrinthi
16) aa. pontis
17 - 21

17) a. inf. post. cerebelli
18) a. vertebralis
19) a. spinalis ant.
20) n. ophthalmicus
21) n. maxillaris
22 - 25

22) n. mandibularis
23) n. oculomotorius
24) rr. ganglionares for ganglion of n. trigeminus
25) rr. tentorii
Which aa. supply the cerebellum?
Which further structure is supplied by them?
- a. basilaris → a. sup. cerebelli
- a. basilaris → a. inf. ant. cerebelli
- a. vertebralis → a. inf. post. cerebelli
additionally plexus choroideus of 4th ventricle
Which areas are partially supplied by a. communicans post.?
It forms an anastomosis btw which aa.?
supplies
- visual pathway
- sub-/hypothalamus (tuber cinereum, corpora mammilaria, pars post. hypothalami), thalamus
forms anastomosis btw a. carotis int. pars cerebralis + a. cerebri post.
Which areas are partially supplied by a. choroidea ant.?
It forms an anastomosis w/ … ?
supplies
- telencephalon (hippocampus, amygdala, ncl. caudatus, pallidum, crus post. of capsula int.)
- thalamus
- midbrain (crura cerebri, substantia nigra, ncl. ruber)
- visual pathway (chiasma opticum, tr. opticus, corpus geniculatum lat.)
- forms rr. of plexus choroideus in lat. ventricles
forms anastomosis w/ rr. choroidei post. from a. cerebri post.
What are the 2 segments of a. cerebri ant.?
Which areas are supplied by it?
2 parts: A1 → a. communicans ant., A2 after
- pars precommunicalis (A1)
- pars postcommunicalis (A2)
⇒ supplies basal part of frontal lobe, medial part of frontal and parietal lobe → sulcus parietoocc.
= sensory/motor centers of lower limbs

What are the 5 branches are given off by a. cerebri ant. A2?
-
a. frontobasilaris medialis, 2. a. polaris frontalis
→basal, medial part of frontal lobe + visual pathway -
a. striata medialis distalis (HEUBNER)
* *→** capsula int., basal ganglia -
a. pericallosa, 5. a. callosomarginalis
* *→** corpus callosum, frontal/parietal lobe + medial parasagittal zone

Which anastomoses are formed by a. cerebi ant.?
a. pericallosa + a. callosomarginalis
- in parasagittal cort. zone w/ a. cerebri med.
- in sulcus parietoocc. w/ a. cerebri post.
What are possible symptoms in case of stenosis of a. cerebri ant.?
insuff. supply of med. gyrus paracentr.
→ contralat. hemiparesis + sens. disorders of leg and foot (+ urinary incont.)

(very rarely due to anastomoses)
What are the segments of a. cerebri med.?
Which areas are supplied by it?
2 parts: M1 → fossa/cisterna lat., M2 after
- pars sphenoidalis M1
- pars insularis M2 = SYLVIAN segment
- sometimes also pars corticalis M3 mentioned
⇒ supplies convexity of brain
= sensory/motor centers of upper limbs, trunk, face, motor center (BROCA) + sensory center (WERNICKE) for speech

What is the most important branch of a. cerebri med. M1.
What do they supply?
aa. lenticulostriatae
→ basal ganglia, capsula int.

Which branches are given off by a. cerebri med. M2?
-
aa. insulares
→insular cortex, claustrum, putamen - rr. terminales (cort.) superiores run superiorly:
- rr. terminales (cort.) inferiores run diagonally post. inferiorly

What are possible symptoms in case of stenosis of a. cerebri med.?
Why is it especially important?
most common site of arteriosclerosis/embolias due to direct extension of course of a. carotis int.
- contralat. hemiplegia + hemianesthesia (esp. head + arm) due to insuff. supply of capsula int. + basal ganglia via aa. lenticulostriatae
- visual deviation to ipsilat. side due to hyperfunction of undamaged hemisphere
if dominant hemisphere affected additionally:
- aphasia due to affected speech centers
- agraphia due to insuff. supply of gyrus angularis

What are the 4 segments of a. cerebri post.?
Which areas are supplied by it?
4 parts: P1 → a. communicans., P2 after → terminal branches = P3, P4
- pars precommunicalis (P1)
- pars postcommunicalis (P2)
- lat term. branch: a. occipitalis lat. (P3)
- med. term. branch: a. occipitalis med. (P4)
⇒ supplies occipital lobe, basal parts of temporal lobes
= visual centers

Which branches are given off by a. cerebri post. P4?
- r. corporis callosi dorsalis anastomoses w/ a. pericallosa
- r. parietalis
-
r. parietoccipitalis + r. calcarinus
→ occipital lobe + visual cortex
What are possible symptoms in case of stenosis of a. cerebri post.?
due to supply of visual system (corpus geniculatum lat., optical radiation, prim. + sec. visual cortex)
- hemianopsia: decreased vision/blindness, usually unilateral
- quadrantanopsia: anopsia in 1 quarter
- scotoma: dark spots in visual field
or:
- thalamic pain syndrome: initial tinglining, followed by numbness + pain
List the 4 segments of a. vertebralis.
Describe their pathways.
- pars prevertebralis enters foramen transversarium of C6
- pars transversaria through foramina transversaria of C6 - C2
- pars atlantica S-shaped, through foramen transversarium of atlas on sulcus a., pierces membrana atlantooccipitalis
- pars intercranialis unites w/ 2nd a. vertebralis to a. basilaris in foramen magnum
Explain the general venous drainage of the brain.

Where does the venous blood from superficial parts of tel- and diencephalon drain into?
vv. superficiales cerebri
- vv. superiores cerebri → sinus sagittalis sup.
- vv. inferiores cerebri → sinus transversus
- v. media superficialis cerebri → both via anastomoses
Where is v. media superficialis cerebri located?
Which important anastomoses does it form?
in sulcus lateralis (SYLVIUS) - (6)
- connected via v. anastomotica superior (TROLARD vein) w/ sinus sag. sup. - (7)
- connected via v. anastomotica inferior (LABBÉ vein) w/ sinus transversus - (8)

Where does the venous blood from the deep parts of tele- and diencephalon drain into?
- vv. profundae cerebri
- paired v. basalis + paired v. interna cerebri (circulus venosus cerebri, TROLARD)
- unite to v. magna cerebri (GALENI) in confluens venosus post.
- unites w/ sinus sagittalis inf. to sinus rectus
Which vv. drain into v. basalis?
Another name.
blood from limbic system, hypo-/metathalamus, mesencephalon, basal ganglia
→ vv. anteriores cerebri + vv. media profunda cerebri
in area of substantia perforata ant.
⇒ v. basalis (ROSENTHAL)
Which vv. drain into vv. internae cerebri?
blood from basal ganglia, thalamus, ventricles
- vv. ant./post. septi pellucidi anastomose w/ v. thalamostriata sup.
- v. thalamostriata sup./inf.
- v. medialis ventriculi lateralis
- vv. directae laterales
- v. choroidea sup./inf. on surface of plexus choroideus

Which vv. drain the cerebellum and the brainstem?
Into… ?
vv. draining into v. magna cerebri:
- v. precentralis cereb.
- v. sup. vermis
- vv. sup. cereb.
vv. draining into. sinus transversus, sinus rectus:
- vv. inf. cereb.
- v. inf. vermis
vv. draining into sinus petrosus sup. via v. petrosus:
- v. pontis
- vv. inf. cereb.
- vv. medullae obl.

What is the importance of vv. emissariae?
vv. w/o valves piercing the calvaria, connecting sinus w/ diploe vv. and skull vv.
→ equilibrate intracranial pressure changes
1 - 5

1) sinus sphenoparietalis
2) sinus cavernosus
3) sinus intercavernosus ant./post.
4) sinus petrosus sup.
5) sinus petrosus inf.
6 - 10

6) plexus basilaris
7) sinus marginalis
8) foramen jugulare
9) sinus sigmoideus
10) sinus transversus
11 - 15

11) confluens sinuum
12) sinus sagittalis sup.
13) sinus rectus
14) sinus sagittalis inf.
15) sinus occipitalis
1 - 6

1) sinus cavernosus
2) hypophysis
3) a. carotis int. pars cerebralis
4) a. carotis int. pars cavernosa
5) chiasma opticum
6) processus clinoideus
some sources say a. carotis int. runs in wall rather than inside the sinus itself
7 - 12

7) sinus sphenoideus
8) n. oculomotorius
9) n. trochlearis
10) n. ophthalmicus
11) n. maxillaris
12) n. abducens
What can be reasons for a venous sinus thrombosis?
Consequences?
- pus from sinus sphenoidalis into sinus cavernosus
- bacteria from v. angularis/v. ophthalmica sup. into sinus cavernosus
⇒ damage n. abducens due to location, later also n. III, IV, V1, V2, meningitis
What is a sinus cavernosus fistula?
arterial blood in sinus cavernosus due to rupture of aneurysm in a. carotis int. → art. pressure
⇒ symptoms: papilledema (swollen orbit, eye lids cannot open, protruding eye ball)
List 4 different bigger vv. emissariae commonly seen.
- vv. em. parietales: through foramina parietalia, connect. sinus sag. sup. w/ vv. temp. sup.
- vv. em. mastoidea: through foramina mastoidea, connect sinus sigmoidei w/ vv. occipitales
- vv. em. condylares: through canales condylares, connect sinus sigmoidei w/ plexus venosus vertebralis ext.
- vv. em. occipitalis: through protub. occip. ext., connects confluens sinuum w/ vv. occipitales
