Arteries-Lecture

Question 1

Anterior cerebral Artery

Answer 1

1) Begins at the internal carotid artery
- Ends at the parieto-occipital sulcus
2) Divided into 5 segments (A1-A5)
3) A1
- precommunicating segment
- internal carotid artery-> superiorly over optic chiams-> anterior communicating artery
4) A2
- infracallosal segment
- Anterior communicating artery-> rostrum and gene of corpus callous meet
- passes rostral (towards head) towards the genu of the corpus and gives rise to frontal orbital branches:
- frontopolar and orbitofrontal braches most frequent
5) A3
- precallosal segment
- portion of the anterior cerebral artery that arches around the genu of the corpus callous
- vessel ends as it turns sharply caudal (towards tail)
- gives rise to the callosomarginal artery and the more anterior middle and internal frontal branches
6) A4 and A5
- supracallosal (A4)
- postcallosal (A5)
- located superior to the corpus callous
- separated by just a line just caudal to the coronal structure
- A5 ends about the position of the parties-occiptal sulcus
7) About 30-35% of all intracranial aneurysms found:
- anterior communicating artery
- vessels where the anterior communicating a. joins the anterior cerebral artery

When they occur on the more distal parts:

• located at the branch points of the frontopolar and callosomarginal arteries
  9) Laminal Terminalis Cistern:
• anterior communicating artery
• Distal parts of A1 segments
• give rise to small branches that serve the anterior hypothalamus and optic chimes
  10) Main branches of A3 to At lie within Callosal Cistern

Question 2

Aneurysm of the anterior communicating artery

Answer 2

1) Visual Deficits
- close proximity to optic chiams
2) Ruptures=Interhemisphere fissure
- between frontal lobes
3) hematomas in the brain itself or blood in ventricles

Question 3

Middle Cerebral Artery

Answer 3

1) Larger than the two terminal branches of internal carotid artery
2) Segments (m1-M4)
3) serves the face, upper extremity, and trunk areas of primary somatomotor and somatosensory cortices
4) M1
- b/w internal carotid_> branches at ventromedial aspect of insula (limen insulae)
- serve adjacent medial and rostral aspects of the temporal lobe and structures located in hemisphere via lenticulostriate arteries
- located in the medial portion of sylvian cistern
- on the ventromedial aspect of the insular cortex, M1 bifurcates into superior and inferior turns
5) Aneurysms of MCA:
- arise at the bifurcation of M1 into the superior and inferior trunks
6) M2
- passes through sylvian cistern and small branches on insular cortex
- serve insular cortex
7) M3
- larger vessels
- inner aspects of operculum (frontal, parietal, temporal)
8) M4
- distal branches of the superior and inferior trunks exit lateral fissure and serve cortices able and below fissure

Question 4

Lenticulostriate arteries

Answer 4

1) in 40% of patients
- originates as single trunk that immediately divides into number of branches that penetrate the hemispheres
2) other patients
- pattern is one of two, several, or many branches that directly form the M1 segment

Question 5

Vertebral Artery

Answer 5

1) Four segments (V1-V4)
-based on anatomic relationships as it ascends in the neck
2) V1
-subclavian artery-> transverse foramen of C6
3) V2
-C6->C2 via transverse foramina
4) V3
-exit of the artery from the C2 foramen -> penetrates the Atlanto occipital membrane
-includes the loop that passes through the transverse foramen of C1 and loops caudally and medially around the lateral mass of the atlas and pierces Atlanta-occipital membrane (where its anchored)
5) V4
-through dura-> joins counter part to form basilar artery
-located within cranial cavity internal to the Atlanta-occipital membrane and dura
-in the subarachnoid space=Lateral Cerebellomedular cistern
6) Branches of the vertebral artery:
-supply the medulla, parts of cerebellum, and the dura of posterior cranial fossa
Vertebral Artery:
-supplies the anterolateral medulla
7) Aneursym not common in major branches
-usually found where the PICA branches from the vertebral Artery
8) Circuitous portion of vertebral A:
-vulnerable to injury
-ex: hyperextension of the head
-deficits VERTEBRObasilar insufficiency

Question 6

PICA

Answer 6

1) PICA
- first major branch of vertebral artery
- arches around the posterolateral medulla
- sends branches to this part of brainstem
2) Posterior portion
- located in cisterna magna
- serves the choroid plexus of the 4th ventricle
- branches over medial parts of the inferior cerebellar surface
3) 75%-posterior spinal artery branch of PICA
- 25% raises from vertebral artery

Question 7

Posterior Spinal Artery

Answer 7

1) 75% branch of PICA
25% branch of Vertebral Artery
2) Serves dorsolateral regions of the medulla caudal to the area served by PICA

Question 8

Anterior Spinal Artery

Answer 8

1) Arises from Vertebral Artery

2) Premedullary Cistern

Question 9

Posterior Cerebral Artery

Answer 9

1) At poi-midbrain Jxn
- basilar artery bifurcate into the interpeduncular cistern-> PCA
2) Each PCA
- passes laterally just rostral (above) the root of the oculomotor nerve
- wraps around the midbrain in the ambient cistern
- then joins the anterior and medial surfaces of the temporal lobe
3) Sends branches to the:
- midbrain
- thalamus
- ventral and medial surfaces of temporal and occipital lobes (up to parietooccipital sulcus)
4) Divided in 4 segments (P1-P4)
5) P1
- located between the basilar bifurcation and posterior communicating artery
- gives rise to small perforating vessels and quadrigeminal and thalamoperforating arteries
6) P2
- posterior communicating a-inferior temporal branches
- give rise to: lateral posterior choroidal and thalamogeniculart arteries and small perforating branches to midbrain
7) P3
- gives rise to temporal branches
8) P4
- occipital and calcimine arteries